®

Lift
Trucks

Service Manual

MicroCommand II Control
2EC15 A2EC1-60001-79999
2EC18 A2EC1-60001-79999
2EC20 A2EC2-60001-79999
2EC25 A2EC2-60001-79999
2EC25E A2EC3-60001-79999
2EC30 A2EC3-60001-79999

SENB8604-02
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Table of Contents

Cat Lift Truck Important Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Component Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Current Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Transistor Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Transistor Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Head Capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Control Panel Thermal Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Contactors Tip Clearance (Gap) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Drive and Pump Motor Shunt Field Resistances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Systems Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Location of Control Panel Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Symbol Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Programmable Setup Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Accessing Programmable Setup Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Operational Circuit Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Run-Time Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Chat Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Contactors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Accelerator Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Drive Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Drive Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Power Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

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Testing and Adjusting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Accessing Stored Fault Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Troubleshooting Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Control And Power System Operational Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Circuit Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

Troubleshooting Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Systems Operation and Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125
Conductor And Switch Continuity Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
Contactor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131
Driver Board Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
Traction Motor Current Sensor Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137

Hydraulics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
Actuation Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
Capacitor Charging Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Hydraulic Pump Motor Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
Lift Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148

Electrical Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160

Testing Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160
Electrical System Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163

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A Power Transistors . . . . . . . . . . . . . . . . . . 34
Regenerative Braking . . . . . . . . . . . . . . . 37
Accelerator
Thermal Protection Circuits . . . . . . . . . . 44
Adjustment . . . . . . . . . . . . . . . . . . . . . . 163
Contactors
Continuity Test . . . . . . . . . . . . . . . . . . . . 128
Continuity Test . . . . . . . . . . . . . . . . . . . . 131
Control Diagnostic . . . . . . . . . . . . . . . . . . 30
General Information . . . . . . . . . . . . . . . . . 30
B Pump Contactor Operation Circuit . . . . 155
Continuity Tests
Battery
Accelerator Control . . . . . . . . . . . . . . . .130
BDI Adjustment Charts . . . . . . . . . . . . . 169
Contactors . . . . . . . . . . . . . . . . . . . . . . . 131
Cell Voltage Test . . . . . . . . . . . . . . . . . . . 49
DC/DC Converter . . . . . . . . . . . . . . . . .133
Hydrometer Test . . . . . . . . . . . . . . . . . . . 49
Diodes . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Load Test . . . . . . . . . . . . . . . . . . . . . . . . . 49
Head Capacitor . . . . . . . . . . . . . . . . . . . 130
Maintenance . . . . . . . . . . . . . . . . . . . . . . 49
Vehicle Monitoring System . . . . . . . . . . 133
Brakes
Control Panel
Parking Brake Switch Adjustment . . . . 164
Component Location . . . . . . . . . . . . . . . 10
Plugging Circuit . . . . . . . . . . . . . . . . . . . . 39
Electrical Testing . . . . . . . . . . . . . . . . . . 162
Regen Circuit . . . . . . . . . . . . . . . . . . . . . . 37
Specifications . . . . . . . . . . . . . . . . . . . . . . 5
Test and Adjust Electric Brakes . . . . . . 167
Thermal Protection Circuit . . . . . . . . . . . 44
Bypass Circuit
Control System Checks . . . . . . . . . . . . . . . . 51
Circuit with Shunt Field Activated . . . . . 45
Circuit Without Shunt Field Activated . . 46
D
C DC/DC Converter
Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Chat Mode . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Continuity Test . . . . . . . . . . . . . . . . . . . . 133
Circuit Tests . . . . . . . . . . . . . . . . . . . . . . . . . 54
Diagnostics
Circuits
Built-In Diagnostic Operation . . . . . . . . . 52
Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Chat Mode . . . . . . . . . . . . . . . . . . . . . . . . 30
DC/DC Converter . . . . . . . . . . . . . . . . . . 31
Run-Time Diagnostic Functions . . . . . . . 52
Drive Control . . . . . . . . . . . . . . . . . . . . . . 32
Run-Time Diagnostics . . . . . . . . . . . . . . . 26
Drive Motor . . . . . . . . . . . . . . . . . . . . . . . 41
Self-Diagnostics . . . . . . . . . . . . . . . . . . . 53
Drive Power . . . . . . . . . . . . . . . . . . . . . . . 33
Stored Fault Codes . . . . . . . . . . . . . . . . . 47
Failure Protection Circuit . . . . . . . . . . . . . 44
Drive Motor
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Hydraulic Circuits . . . . . . . . . . . . . . . . .138
Current Limit . . . . . . . . . . . . . . . . . . . . . .43
Plugging Circuit . . . . . . . . . . . . . . . . . . . . 39
Drive Control Circuit . . . . . . . . . . . . . . . . 32

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Drive Power Circuit . . . . . . . . . . . . . . . . . 33 Lift Power . . . . . . . . . . . . . . . . . . . . . . .149

Electrical Testing . . . . . . . . . . . . . . . . . .162 Power Steering Idle . . . . . . . . . . . . . . . . 141
Thermal Protection Circuit . . . . . . . . . . . 44 Power Steering In Use . . . . . . . . . . . . . 146
Driver Board Tests Pump Contactor . . . . . . . . . . . . . . . . . . 155
Chart . . . . . . . . . . . . . . . . . . . . . . . . . . .135 Pump Motor . . . . . . . . . . . . . . . . . . . . . 140
Drive Driver Board . . . . . . . . . . . . . . . . . 134 Pump Power Transistor Turn-Off . . . . . 158
Pump Driver Board . . . . . . . . . . . . . . . . 134 Pump Shunt Field . . . . . . . . . . . . . . . . . 145
Pump Shunt Field Circuit . . . . . . . . . . . 145
E Tilt and Auxiliary Control . . . . . . . . . . . . 156
Electrical System Adjustments . . . . . . . . . . 163
Method A (Mechanical) . . . . . . . . . . . . . 163 L
Method B (Electrical) . . . . . . . . . . . . . . . 163 Lift Control
Electrical Tests and Adjustments Additional Information . . . . . . . . . . . . . . 157
Accelerator Group . . . . . . . . . . . . . . . . . 163 Lift Control Circuit . . . . . . . . . . . . . . . . . 148
Current Limit Test and Adjust . . . . . . . . 166 Lift Power Circuit . . . . . . . . . . . . . . . . . .149
Electric Braking . . . . . . . . . . . . . . . . . . .167 Logics
Harness Wiring Circuit Guide . . . . . . . . 171 Circuit Elements . . . . . . . . . . . . . . . . . . . 23
Logic Board Layout . . . . . . . . . . . . . . . . 168 Component Tests . . . . . . . . . . . . . . . . . 126
Park Brake Switch . . . . . . . . . . . . . . . . . 164 Removal . . . . . . . . . . . . . . . . . . . . . . . . . 126
Resistor R312 . . . . . . . . . . . . . . . . . . . . 162 Test Board Layout . . . . . . . . . . . . . . . . .168
Transistor Replacement . . . . . . . . . . . . 161 Voltage Check . . . . . . . . . . . . . . . . . . . . 127
Transistors . . . . . . . . . . . . . . . . . . . . . . . 160 Voltage Test Chart . . . . . . . . . . . . . . . . . 128

G O
General Information . . . . . . . . . . . . . . . . . . . 14 Operational Circuit Elements . . . . . . . . . . . . 23
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
P
H Power Steering
Harness Wiring Circuit Guide . . . . . . . . . . .171 Power Steering Idle . . . . . . . . . . . . . . . . 141
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Power Steering In Use . . . . . . . . . . . . .146
Hydraulic Circuits . . . . . . . . . . . . . . . . . . . . 138 Power System Checks . . . . . . . . . . . . . . . . . 51
Actuation Circuit . . . . . . . . . . . . . . . . . . 138 Programmable Setup Options
Capacitor Charging Circuit . . . . . . . . . . 139 General Information . . . . . . . . . . . . . . . . . 15
Flyback Circuit . . . . . . . . . . . . . . . . . . . . 147 Setup Option 1 . . . . . . . . . . . . . . . . . . . . 21
Lift Control . . . . . . . . . . . . . . . . . . . . . . . 148 Setup Options Other Than Option 1 . . . .22

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R
Rapid Tune-Up . . . . . . . . . . . . . . . . . . . . . . 165

S
Safety Information . . . . . . . . . . . . . . . . . . . . . . 1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 2
Stored Fault Codes . . . . . . . . . . . . . . . . . . . . 47
Symbol Library . . . . . . . . . . . . . . . . . . . . . . . 11
Systems Operation and Test Equipment
Continuity Tests
Head Capacitor . . . . . . . . . . . . . . . . 130

T
Test Equipment . . . . . . . . . . . . . . . . . . . . . . 125
Testing and Adjusting . . . . . . . . . . . . . . . . . . 47
Thermal Protection Circuits . . . . . . . . . . . . . 44
Tilt/Auxiliary Control
Tilt/Auxiliary Circuit . . . . . . . . . . . . . . . . 156
MicroCommand II Control Panel . . . . . . . . .13
Transistors
Electrical Tests . . . . . . . . . . . . . . . . . . . . 160
Power Transistor Circuit . . . . . . . . . . . . . 34
Replacement . . . . . . . . . . . . . . . . . . . . . 161
Troubleshooting
Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Checklist . . . . . . . . . . . . . . . . . . . . . . . . . 48
Circuit Tests . . . . . . . . . . . . . . . . . . . . . . . 54
Preparation Tests . . . . . . . . . . . . . . . . . . . . . 49

V
Vehicle Monitoring System Display Unit
Circuit Test . . . . . . . . . . . . . . . . . . . . . . . 133
General Information . . . . . . . . . . . . . . . . . 24

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Cat Lift Truck Important Mitsubishi Caterpillar Forklift America Inc. (MCFA) can-
not anticipate every possible circumstance that might
Safety Information involve a potential hazard. The warnings in this publi-
cation and on the product are therefore not all-inclu-
Most accidents involving product operation, mainte- sive. If a tool, procedure, work method or operating
nance and repair are caused by failure to observe basic technique not specifically recommended by Mitsubishi
safety rules or precautions. An accident can often be Caterpillar Forklift America Inc. (MCFA) is used, you
avoided by recognizing potentially hazardous situations must satisfy yourself that it is safe for you and others.
before an accident occurs. A person must be alert to You should also ensure that the product will not be
potential hazards. This person should also have the damaged or made unsafe by the operation, lubrication,
necessary training, skills and tools to perform these maintenance or repair procedures you choose.
functions properly.
The information, specifications, and illustrations in this
Improper operation, lubrication, maintenance or repair publication are on the basis of information available at
of this product can be dangerous and could result in the time it was written. The specifications, torques,
injury or death. pressures, measurements, adjustments, illustrations,
Do not operate or perform any lubrication, mainte- and other items can change at any time. These
nance or repair on this product, until you have read changes can affect the service given to the product.
and understood the operation, lubrication, maintenance Obtain the complete and most current information
and repair information. before starting any job.
Safety precautions and warnings are provided in this Cat lift truck dealers have the most current information
manual and on the product. If these hazard warnings available.
are not heeded, bodily injury or death could occur to
you or other persons.
The hazards are identified by the “Safety Alert Symbol”
and followed by a “Signal Word” such as “WARNING”
as shown below.

! WARNING
The meaning of this safety alert symbol is as follows:
Attention! Become Alert! Your Safety is Involved.
The message that appears under the warning, explain-
ing the hazard, can be either written or pictorially pre-
sented.
Operations that may cause product damage are identi-
fied by NOTICE labels on the product and in this publi-
cation.

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Specifications
Component Measurements
Component Meter Scale Meter Positive (+) Test Meter Negative (-) Test Desired Indication
Lead Lead
Diodes (voltage indication)
All Diode Anode Cathode 0.3 to 0.9 Volts
All Diode Cathode Anode OL
Resistors (resistance indication)
36/48 34.20—37.80 ohms
R312 200 ohms
72/80 71.25—78.75 ohms

Head Capacitor (resistance indication)

Head Capacitor 20 K ohms Positive side of capacitor Negative side of capacitor 0 then change to
(+) (-) above 10 K ohms
Contactor Coils (resistance indication)
Directional (Forward) 200 ohms X Y 32.31—39.49 ohms1
Directional (Reverse) 200 ohms X Y 32.31—39.49 ohms1
Line 200 ohms X Y 32.31—39.49 ohms1
Bypass 200 ohms X Y 32.31—39.49 ohms1
Pump 200 ohms X Y 32.31—39.49 ohms1
Regen 200 ohms X Y 32.31—39.49 ohms1
1
Measured Resistance with room temperature coil (75°F) and terminals disconnected (coil isolated)

Current Measurements
Current Limit (amps) Regnen Braking Current (amps)
Model
36/48V 72/80V 36/48V 72/80V

2EC15/18 380 - 420 A — — —

2EC20/25/25E 475 - 525 A 400 - 450 A 285 - 315A 190 - 210A
2EC30 500 - 550 A 425 - 475 A 285 - 315A 190 - 210A

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Transistor Measurements Head Capacitor

Multimeter (+) Test (–) Test 927566 974222 NOTE: Proper torque and assembly of capacitor hard-
Setting Lead Lead Results Results ware is critical. Avoid disassembly unless capacitor has
to be replaced.
Resistance Emitter Base 45 to 135Ω 60 to 180Ω
1. Tighten capacitor terminal screw to a torque of
Diode Base Collector .3 to.9V .3 to.9V 5± 0.5N•m (50 ±5 lb in).
Diode Collector Base OL OL 2. Spring washer 8T2229 concave side down.
3. Bus bar assembly 925789.
Diode Emitter Collector .3 to.9V .3 to.9V
4. Lockwasher 8C3398.
Diode Collector Emitter OL OL
5. Head capacitor terminal.

Transistor Connections 1 2

1 2 4
3

C30610P1

3
C30706P1

1. Emitter
2. Base
3. Collector

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Control Panel Thermal Switch Drive and Pump Motor

Contacts open at . . . . . . . 81 to 89° C (178 to192° F) Shunt Field Resistances
Contacts close at . . . . . . . 69 to 77° C (156 to 171°F) Model Drive Motor Shunt Field Pump Motor Shunt Field
Resistances (ohms) Resistances (ohms)
Contactors Tip Clearance (Gap) 9” Diameter GE Motor 7” Diameter GE Motor
Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .no adjustment 2EC15/18 36/48 V 72/80 V 36/48 V 72/80 V

Directional (Forward and Reverse) . . . . . .3.05mm ± 7% 11.09- 27.99- 8.55- 23.76-

13.55 Ω 34.21 Ω 10.45Ω 29.04Ω
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(0.120” ± 7%)
11” Diameter GE Motor 9” Diameter GE Motor
Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . .no adjustment 36/48 V 72/80 V 36/48 V 72/80 V
2EC20-30
Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . .no adjustment 3.78- 33.07- 29.16- 11.52-
Regen . . . . . . . . . . . . . . . . . . . . . . . . . . . .no adjustment 4.62Ω 40.43Ω 35.64Ω 14.08Ω

Fuses
Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 A
Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 A
Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .675 A
Shunt Field Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 A

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Control Panel
7 3

Torques
R - 5 ± 1N•m
V - 7.5 ± 2N•m
T - 12 ± 2N•m

14
11

12

15

97C54-11300

NOTE: Apply a small amount of 5P8937 Thermal 8. Tighten bolt that holds the bar to the negative
Joint Compound on the surface of the transistor, heat sink to the control panel to a torque of
diode or thermal switch that contacts the heat sink. 4 to 6 N•m (35 to 55 lb in)
9. Tighten bolt to a torque of
1. Tighten the bolts that fasten the bus bar and cable 4 to 6 N•m (35 to 55 lb in)
to the heatsink (R) to a torque of
4 to 6 N•m (35 to 55 lb in) 10. Tighten bolts that hold the negative heatsink to
2. Tighten the bolts that hold the positive heat sink to the control panel (V) to a torque of
the control panel (T) to a torque of 5.5 to 9.5 N•m (40 to 84 lb in)
10 to 14 N•m (90 to 125 lb in.) 11. Tighten diode 4 pump (D4P) to torque of
3. Tighten the bolts that fasten the bus bars to the 13N•m (116 lb in)
power transistors to a torque of 12. Tighten diode 4 drive (D4D) to a torque of
4 to 6 N•m (35 to 55 lb in) 36 N•m (320 lb in)
4. Tighten head capacitor terminal bolts to a torque of 13. Tighten the bolt that holds the shunt (R) to a torque of
4.5 to 5.5 N•m (40 to 50 lb in) 4 to 6 N•m (35 to 55 lb in)
5. Tighten bolts that fasten power transistors to the 14. Tighten diode 5 drive (D5D) to a torque of
positive heat sink (R) to a torque of 36 N•m (320 lb in)
4 to 6 N•m (35 to 55 lb in)
15. Use a backup wrench to hold bolts and tighten
6. Apply 9S3263 Thread Lock on the threads of all the nuts that fasten the cables or bus bars to the
screws that are used to fasten components on the contactors to a torque of
control panel. 8 N•m (71 lb in)
7. Tighten screws at power transistor base connec-
tions to a torque of
1.3 to 1.7 N•m (11.5 to 15 lb in)
5
SENB8604-02

Systems Operation Capacitor

Device used to store electrical energy for short
Glossary periods of time.
Cathode
Accelerator The negative (-) side of a diode.
A device that converts mechanical movement into
a digital voltage pattern to the logics for variable Circuit
drive motor speed. A way for current to go from the positive (+) side of
an electrical power source to the negative (-) side
Activate of an electrical power source. This can be through
A word used with a component or circuit. To wires and electrical components.
change from the normal condition to the “activated”
condition because of an application of force or Coil
electricity. A component made from many circles or turns of
wire used to concentrate a magnetic field.
Ammeter
An electric meter used to measure current flow in Collector
amperes. A terminal of a transistor through which main
current flows (see Transistor).
Ampere (or Amp)
The unit of measurement of current flow. The Commutator
amount of current that one volt can push through a An armature component used to transfer current
resistance of one ohm. from the brushes to the armature windings.

Analog to Digital Converter Compound Motor

A device that converts an analog voltage into a A motor which has a field winding in series with the
pattern of digital HIGH and LOW voltage signals. armature and a shunt field winding in parallel with
the series winding and armature.
Anode
The positive (+) side of a diode. Compound/Series Motor
Similar to a compound motor, except the parallel
Armature shunt field windings are controlled on and off to
The rotating portion of an electric motor or vary speed and torque.
generator.
Conduct
Base To allow the flow of current.
The terminal of a transistor through which control
current flows (see Transistor). Conductor
A material that provides a path for current flow.
Battery
Two or more cells connected together for a supply Connector
of electric current. Part of a wire assembly or harness that connects
with another wire assembly or harness. Used for
BDI (Battery Discharge Indicator) ease of assembly and disassembly.
An electrically controlled display showing the
operator the state of battery charge. Contactor Assembly
An electrical component consisting of an electro-
Brush magnetic coil and a set of heavy contact tips.
A conductor, normally a block of carbon, that Control current passes through the coil, building a
makes sliding contact between the stationary and magnetic field which closes or opens the contact
moving part of the motor or generator. tips.
Bus Bar Contactor Coil
A heavy electrical conductor to which other smaller An electromagnet used to close or open contact
wires are connected. tips in a contactor assembly.

6
 SENB8604-02

Contact Tips or Contacts Drain

The portion of a switch, relay or contactor where Terminal of a MOSFET through which main current
the circuit can be opened or closed. flows (see MOSFET).
Continuity Electrical Braking
Having the ability to allow current flow. Electrically trying to rotate the drive motor opposite
to the direction of truck movement.
Control Circuits
The wires and components carrying low current Electromagnet
used to signal the logics unit, turn on main compo- A coil of wire, most often wound on an iron core,
nents, or support auxiliary circuits (indicated by which produces a strong magnetic field when
thin lines on a schematic). current is sent through the coil.
Counter Electromotive Electromotive Force (EMF)
An opposing voltage set up by a collapsing or The force that causes an electric current to flow in
increasing magnetic field within a Force (CEMF) a circuit. This force is measured in volts.
coil.
Emitter
Current A terminal of a transistor through which low control
The movement or flow of electricity through a current and main current flow (see Transistor).
conductor. A circuit must be complete for current
Ferrite Bead
to flow.
A small bead located on the base connection of
Current Limit the power transistors to reduce high frequency
The maximum allowable armature current of a oscillation at the power transistor.
stalled drive motor during pulsing.
Field Windings
Current Sensor The stationary coils that produce a magnetic field
A hall-effect sensor in the drive motor circuit that in motors and generators.
produces an increasing voltage output as the drive
Filter
motor current increases.
An electrical device or component for restriction or
Current Shunt suppression of undesired voltage spikes.
A precision low-value resistor connected in series
Fuse
with the armature of a motor. The logics uses the
A component in an electrical circuit that will open
measured voltage drop across the shunt to control
the circuit if too much current goes through it.
maximum current allowed in selected power
circuits. Gate
Terminal of a MOSFET where voltage is applied to
Deactivate
control the device (see MOSFET).
To change from the activated condition back to the
normal (deactivated) condition. It can be caused Grounded
by the application of force, the removal of force, or A wire or wires that are in contact with the metal
the removal of electricity. chassis of the vehicle (ground). Can be caused by
a loss of insulation from the wire, or by connecting
Digital Signal
the wire to the vehicle.
A signal in which the elements may be either of
two distinct values. For example high voltage, low Harness
volt age. An assembly made of two or more wires that are
held together.
Diode
A semiconductor device that allows current to flow Heat Sink
in one direction, from the anode to the cathode. A mounting frame used for semiconductor cooling.
Display Hour Meter
An electrical device that converts voltage inputs to An electrically activated device used to record the
a visual output. amount of usage a truck receives.

7
SENB8604-02

Indicator Normal Condition

A lamp or LED that gives an indication of some Words used with a switch or relay. Their normal
vehicle condition when it turns on or flashes. condition is their condition when they are not
controlled by the application of force, temperature,
Input
pressure, or electricity.
A voltage change at the incoming connection of a
component. Normally Closed (N.C.)
A switch or relay whose contacts are closed in the
Insulator
normal condition.
A material that has a very large resistance so that
it will not let current flow through it. Normally Open (N.O.)
A switch or relay whose contacts are open in the
LED
normal condition.
Light Emitting Diode - a diode that emits light
(lights) when current flows in the forward direction. OFF-Time
The amount of time current does not flow through
Linear Output Hall Effect Transducer (LOHET)
a transistor.
A device that converts an increasing magnetic field
to an increasing linear output voltage Ohm
The unit of measurement of resistance. The
Logics or Logic Unit
amount of resistance that will let one volt push
The main printed circuit board containing a micro
only one ampere of current through it.
processor and circuits to condition the voltage
signals that go into or come out of the logics. It ON-Time
electronically monitors and controls the truck’s The amount of time current flows through a
functions. transistor.
Magnetic Field Open Circuit
The area around a magnet where magnetic forces Wiring or components of a circuit that have no
can be detected. continuity.
Microprocessor Optical Switch
A small computer chip preprogrammed to control An electronic device made up of an infrared light
the various electrical functions on a lift truck. signal generator and photosensitive signal receiver
that changes a digital voltage when the light
MOSFET
pattern is conducting or blocked.
A semiconductor component used in electrical lift
trucks as an electronic switch. A MOSFET most Output
often has three terminals: a Gate (G) a Source (S) The current flow from a component which is initiated
and a Drain (D). The main current flows between from a voltage change at the component’s input.
the drain and the source. The main current flow is
Source
controlled by a voltage applied between the gate
Terminal of a MOSFET through which the main
and the source.
current flows (See MOSFET).

8
 SENB8604-02

Terminal Volt
An electrical connection point on an electrical The unit of measurement of electromotive force.
component. One volt is the force needed to make one ampere
of current flow through one ohm of resistance in a
Thermal Switch
circuit.
A switch that activates at a set temperature.
Watt
Transistor
The unit of measurement of power. The amount of
A semiconductor component used in electric lift
power used when one volt pushes one ampere of
trucks as an electronic switch. A transistor most
current through a resistance of one ohm. The
often has three terminals, a base (B), a collector
result of amperes (current) multiplied by volts (volt
(C), and an emitter (E). The main current flow is
age) is watts (power).
between the collector and emitter. This main
current flow is controlled by a much smaller Wire
current flow between the base and emitter. A conductor used to provide a path for current to
flow to and from electrical components.
Turn ON
When an electrical component conducts current. Wiring Diagram
A drawing using visual representation of compo
Varistor
nents the way they actually look. It is used to show
A component terminated across the horn connec-
the locations of components and the connections
tions to eliminate voltage spikes when the horn is
between them.
activated.
Zener Diode
A special diode used to regulate voltage or as an
overvoltage (too high a voltage) protector.

9
SENB8604-02

Location of Control Panel

Components
MicroCommand II Control Panel
1. Logic unit (logics)
2. Head capacitors
3. Line fuse
4. Battery negative connection
5. Line contactor
6. Battery positive connection
7. Lift contactor
8. Bypass contactor
9. Forward contactor
10. Reverse contactor

CP Components

10
 SENB8604-02

Symbol Library

1 2 3 4 5 6 7 8
9

10

11

12

13

14

15

16

24 17
23 22 21 20 19 18

24 25
28

26 27

Schematic Symbols
(1) Power Transistor (2) Zener Diode (3) Ferrite Bead
(4) NPN Transistor (5) PNP Transistor (6) Thermal Switch
(7) Switch (8) Battery (9) Resistor
(10) Diode (11) Normally closed contacts
(12) Normally open contacts (13) Armature
(14) Male contact of a connector (pin)
(15) Female contact of a connector (socket)
(16) Wire Connection (17) No wire connection
(18) Contactor Coil (19) Current Shunt
(20) Field Windings (21) Capacitor (22) Varistor of Wires
(23) Fuse (24) Switch (25) N-Channel MOSFET
(26) P-Channel MOSFET (27) Twisted Pair
(28) Hall Effect Current Sensor (29)Thermistor

11
SENB8604-02

Components Behind Logic Unit (1)

1)Pump driver board 13)P5 Main wiring harness connector 14)Auxiliary fuse holder 15) Key fuse 16)Accessory
fuse 17) Resistor R312 18)T2P transistor 19) Drive Driver Board 20) T1P(Transistor one pump) 21) T1D
(Transistor one drive) 22)Thermal Switch 23)T2D(Transistor two drive ) 24)Negative heatsink

Control Panel and Driver Board with Regen / 10300V2

Control Panel and Driver Boards Plug Only / 10200V2

12
 SENB8604-02

MicroCommand II Control Panel

1)PS main wiring harness connector 2)Head capacitors 3)Line Fuse 4) Battery negative connection 5)Line
contactor 6)Battery positive connection 7)Pump Contactor 8)Traction Bypass Contactor 9)Forward contactor
10)Reverse contactor

Control Panel Cover off with Regen / 10300V3

Control Panel Cover off Plug Only / 10200V3

13
SENB8604-02

General Information The MicroCommand II control system operates the

drive motor and the hydraulic pump motor systems on
When the term 2EC is used, it refers to the 2EC family the 2EC family of lift trucks. The steering system is
of lift trucks, which includes the 2EC15, 2EC18, activated when the truck is powered up and the line
2EC20, 2EC25, 2EC25E, and 2EC30 models. contactor closes. The truck uses a combined power
The MicroCommand II panel is the control center of the steering/hydraulic system where the hydraulic fluid
2EC family of lift trucks. The Logic Unit (logics) is the power for steering is provided by a hydraulic motor,
decision-making part of the control system. The logics pump, and priority valve.
provides a self-contained Battery Discharge Indicator The speed of the hydraulic motor is controlled by volt-
(BDI) with lift interrupt and built-in diagnostics capability. age inputs to and outputs from the logics. Inputs are
The logics monitors the battery state of charge and the generated by a pressure switch (steering) and valve
diagnostics. It also displays related information to the control switches (lift 1, lift 2, auxiliary 1 and auxiliary 2).
operator on the liquid crystal display (LCD) panel located
on the steer console. Outputs pulse hydraulic pump power transistors and the
pump shunt field, and they control the pump contactor
Four jumper connectors located on the logic card are coil. The power transistors pulse in order to control the
used to select the appropriate battery voltage: speed of the hydraulic pump motor. To provide full
J1=36V J2=48V J3=72V J4=80V speed, the logics activates the pump contactor, stops
pulsing the power transistors, and turns off the pump
If the wrong voltage is selected by the jumper position, shunt field. A failure protection circuit is also included to
the lift truck will not operate, and the display will show a protect against malfunctions of the power circuit.
fault code (68 or 69). See the topic, On-Board “Run Time”
Diagnostics later in this section of the manual. The speed and direction of the drive motor is controlled
by voltage inputs to and outputs from the logics. Inputs
to the logics are generated by the accelerator control
and direction switch. Outputs from the logics control
contactor coils, drive transistor pulsing, and drive shunt
field.
The drive circuit pulses transistors to provide travel
speed control up to 90% of full speed. Above that, the
bypass contactor closes and the drive shunt field turns
off to provide full speed. The drive circuit includes a
failure protection circuit that detects malfunctions of
the drive power circuit, a regenerative braking circuit
(standard on 2EC20 - 30 models), or a plugging circuit
(standard on 2EC16 - 18 models), and a current limit
C0000 circuit to prevent excessively high currents during
transistor pulsing.
If the jumper is lost, the default voltage is 36V for the Thermal protection circuits are used on the hydraulic
logic card. pump motor, the drive motor, and the control panel to
prevent permanent damage caused by overheating.

14
 SENB8604-02

Programmable Setup Options

Thirty one programmable setup options are available
on the 2EC family of electric lift trucks equipped with
MicroCommand II control system. These options can
be set by the user so that truck performance best
matches the operating conditions under which the truck
will be used.
The thirty options are divided into three groups:
Group 1: Setup options 1 - 9
Group 2: Setup options 10 - 27
Group 3: Setup options 28 - 35
The following chart shows a list of all thirty-one options
in their three groups. Minimum settings, maximum set-
tings, and the factory defaults are given in the chart.
For more information on using the Programmable
Setup Options, see the following topics in this section
of the manual.
• Functional Descriptions of Programmable Setup
Options
• Accessing Programmable Setup Options
• Programming Setup Option 1
• Programming Setup Options (Other than Option 1)
• Activating Default Settings.

15
SENB8604-02

PROGRAMMABLE SETUP OPTIONS

FIRST GROUP
Settings
Option No. Min. Max. Default Description
1 A E A Truck Mode Option
2 0 10 5 Lift 1 Speed (Pump Motor Speed)
3 0 10 8 Lift 2 Speed (Pump Motor Speed)
4 2 7 3 Tilt Speed
5 0 10 3 Aux 1 Speed
6 0 10 0 Aux 2 Speed
7 5 20 16 Top Drive Speed
8 1 16 10 Variable Acceleration
9 0 = Disable .1 = for sales demo only Service Reminder Interrupt
100.0, 150.0, 200.0, 250.0, 300.0, 350.0,
400.0, 450.0, 500.0 0
SECOND GROUP
10 0 4 0 Auxiliary Input for Lift and Drive Speed
11 1 20 10 Auxiliary Travel Speed Limit
12 3 15 5 Pulsing Stall Timer
13 0 15 3 Park Brake Duty Cycle Limit
14 0 1 1 BWI Operation
15 0 1 1 80% Bypass Option
16 0 10 5 BDI Reset Value
17 0 1 1 Dead Battery Lift Lockout
18 0 20 10 Dead Battery Travel Speed with Disable
19 0 1 0 Variable Regen on Accelerator (Regen only)
20 0 3 3 Regen Function on Accelerator or Brake (Regen only)
21 0 1 0 Regen Enable for 1T 2EC 36/48V Trucks
22 0 15 3 Service Brake Duty Cycle Limit
23 0 20 5 Chat Timer
24 0 1 0 French BDI Option (nonactive)
25 0 1 0 Pump and Drive Pulsing Frequency
26 3 10 5 Regen Adjustment for Brake Regen
27 0 2 0 Pump Transistor Upgrade
THIRD GROUP
28 0 2 0 EE Option
29 0 40 20 Tire Size Adjustment
30 0 C 0.0 C 1.5 C 2.0 C 2.5 C 3.0 Truck Size and Type
31-34 0 0 0 Blank
*35 1.5 20 1.5 Bypass Stall Timer
* Any setting above 3 seconds may cause severe damage to traction motor. Contact Service Engineering before changing.
16
 SENB8604-02

Functional Descriptions of Option 4 - Tilt Speed

• Settings: 2/7/3
Programmable Setup Options This option performs the same function as option
2, except that it sets up the tilt control.
NOTE: The three numbers separated by “/ ” following
“Settings” indicate the minimum value/maximum Option 5 - Aux 1 Speed
value/factory default value. These are the same values • Settings: 0/10/3
given in the Programmable Setup Options table on the This option performs the same function as option
preceding page of this manual. 2, except that it sets up the Aux 1 control.
First Group
Option 6 - Aux 2 Speed
Option 1 - Truck Mode • Settings: 0/10/0
• Settings: 1/5/1 This option performs the same function as option
This option is used to preset the value of seven 2, except that it sets up the Aux 2 control.
other options. This allows the user to set the truck
up for one of five various modes of operation: Option 7 - Top Speed Option
standard Factory, Hi-Performance, Economy, • Settings: 5/20/16 (5-20 KPH)
Long-Travel, or Dock. Option 1 is a convenient This option can be used to control the top speed
way to program truck performance without having of the truck. This option will NOT apply the
to program many options individually. It is never- brakes if the speed limit is exceeded (i.e. going
theless possible to modify the preset values of the down a hill). Also, you must be careful not to set
options that make up the chosen application. See the speed limit to a value that would keep the
the topic, “Programming Setup Options - Option truck out of bypass unless this is absolutely
1” later in this section. necessary. Without bypass the panel will be
more likely to overheat in an application.
Option 2 - Lift 1 Speed
• Settings: 0/10/5 Option 8 - Variable Acceleration
This option, and options 3, 4, 5, and 6 (see below), • Settings: 1/16/10 (SLOWEST/FASTEST)
allow the user to select the preferred pump motor This option will allow the acceleration of the
speed for the Lift 1 speed control. The chart below truck to be controlled. It is much like the
shows the range of possible speeds that can be rabbit/turtle switch that other lift trucks offer.
programmed.
Pump Speed Armature Shunt Field Duty Pump Option 9 - Service Reminder Interrupt (SRI)
Duty Cycle Cycle Contactor • Settings:
• Increment Values:
0 0% 100% Off 0 = Disable
1 15 100 Off 000.1 For sales use only. 100.0, 150.0, 200.0,
250.0, 300.0, 350.0, 400.0, 450.0, 500.0
2 20 100 Off This option allows you to do either of two things.
3 25 100 Off You can merely have the Service Reminder
action light come on when the selected time
4 35 100 Off
increment is reached; or, you can activate the
5 45 100 Off light and also shut off the lift, tilt, and auxiliary
6 55 100 Off functions and slow the truck to the dead battery
travel speed (option 18). The increment values
7 70 100 Off represent hundreds of hours. They appear on the
8 0 100 On display in two groups. The second group, which
is indicated by an equal sign preceding the incre-
9 0 50 On
ment value, will shut off the lift, tilt, and aux func-
10 0 0 On tions and reduce travel speed. The SRI will be
reset every time the DIAG/RUN/SETUP switch is
Option 3 - Lift 2 Speed toggled past this option. If you enter this option
• Settings: 0/10/8 and do NOT wish to reset the SRI, simply turn off
This option performs the same function as option the key switch.
2, except that it sets up the Lift 2 control.

17
SENB8604-02

Second Group Option 16 - BDI Reset Value

• Settings: 0/10/5 0-10 RESET VALUE
Option 10 - Auxiliary Input For Lift And Drive Speed This option sets the value above which we
• Settings: 0/4/0 consider a battery to be recharged. If the truck
0 Disabled enters a dead battery condition, it will remain in
1 Disable Lift On Low this state even if the key switch is cycled until a
2 Speed Limit On Low battery that equals or exceeds the BDI reset value
3 Disable Lift On High is connected to the truck.
4 Speed Limit On High
• This option is used in conjunction with the lift limit Option 17 - Dead Battery Lift Lockout
input P1-14. This input is internally pulled up on • Settings: 0/1/1 OFF/ON
the logic to +15V. This option determines the action of the lift during
a dead battery condition.
Option 11 - Auxiliary Travel Speed Limit
• Settings: 1/20/10 Option 18 - Dead Battery Travel Speed With Disable
This option is used in conjunction with option 10 • Settings: 0/20/10 1 - 20 KPH WITH 0 = DISABLE
when the speed limit portion of option 10 is used. This option determines the maximum truck speed
during a dead battery condition.
Option 12 - Pulsing Stall Timer
• Settings: 3/30/5 Option 19 - Variable Regen On Accelerator
This option allows some adjustment (3 to 30 • Settings: 0/1/0 OFF/ON
seconds) to the time it takes the truck to shut When enabled, this option allows the accelerator to
down when the drive motor current is too high for control the level of braking in regen. The option
too long in transistor mode. This condition, called a works only on trucks equipped with regen. It is
drive stall timer failure, produces an error code 20 influenced by the setting of option 20. (It will not
on the display. Option 12 helps prevent drive motor work with settings EAB1 or EAB3 because they
abuse. require the accelerator to be off.)
Option 13 - Park Brake Duty Cycle Limit
Option 20 - Regen Function On Accelerator Or Brake
• Settings: 0/15/3 • Settings: 0/3/3
This option controls the maximum drive duty cycle 0 DISABLED/EAB1/EAB2/EAB3
when the park brake is applied. It allows the drive 1 EAB1 - Service Brake is on; Accel must be off
system to operate much like a car when the park 2 EAB2 - Service Brake is on; Accel does not matter
brake is applied. The truck will try to move, but be 3 EAB3 - Whenever accel is off
unable. This should help remind the operator that
the park brake is applied. This option allows the use of the Electrical
Assisted Braking (EAB). The three modes are
Option 14 - BWI Operation defined above. Only one mode can be enabled at a
• Settings: 0/1/1 time. This option works only on trucks equipped
NO EFFECT/BWI AFFECTS TRUCK OPERATION with regen because the added braking load would
This option determines what will happen if either overheat a truck equipped only with plugging.
the drive or pump motor brush wear indicator
(BWI) is activated: Option 21 - Regen Enable For 2EC15/18 36/48V Truck
• Pump BWI active - Lift Lockout • Settings: 0/1/0 DISABLED/YES
• Drive BWI active - Truck is slowed to 1/2 of This option allows a person to enable regen on a
current maximum speed or 6 KPH, whichever truck that did not previously have regen. After the
is slower. necessary components have been added, this
option is enabled.
Option 15 - 80% Bypass Option
• Settings: 0/1/1 OFF/ON Option 22 - Service Brake Duty Cycle Limit
If enabled, this option will not allow the truck to • Settings: 0/15/3 ACCEL POS LIMIT
enter bypass when the truck is in current limit. This This option controls the maximum drive duty cycle
option in conjunction with the drive pulsing stall when the service brake is applied. This allows
timer (option 12) will help to reduce drive motor some drive while the service brake is on so that the
abuse in hard applications. truck can be two-footed. If the truck is being
abused because of two-footing, option 22 can be

18
 SENB8604-02

used to prevent the situation. Third Group

Option 23 - Chat Timer Option 28 - EE Option
• Settings: 0/20/5 • Settings: 0/2/0
1-20 SECOND TIMER WITH 0=DISABLE OFF/EE DRIVE ONLY/EE DRIVE&PUMP
This option controls the amount time required to The EE option is used to slow down the pump and
enter chat mode. drive system, which results in cooler running motors.
The EE option accomplishes this by always keeping
Option 24 - French BDI Option (nonactive) the shunt field on when the motor is operating.
• Settings: 0/1/0 OFF/ON
This option allows the use of a different BDI Option 29 - Tire Wear Adjustment
discharge curve for use with tubular plate batteries. • Settings: 0/40/20 =
These batteries have a flatter discharge curve than NO ADJUSTMENT SMALLEST/LARGEST
normal so the voltage at which they are considered This option allows the speedometer to be adjusted
dead is higher than the normal battery. See the based on the amount of tire wear. The speedometer
topic, “Battery Discharge Indicator (BDI) calculations are based on a certain tire size. If we
Adjustment,” in the Testing and Adjusting section deviate from this tire size, the speedometer will not
of this manual. work.

Option 25 - Pump And Drive Pulsing Frequency Option 30 - Truck Size and Type
• Settings: 0/1/0 NORMAL/DOUBLE FREQUENCY • Settings: SIZES SHOWN:
This option allows the 187.5 Hz transistor pulsing O 0 0.0 C 1.6 C 1.8 C 2.0 C 2.5 C 3.0
frequency used for drive and lift related pump This option is used to tell the logics the size and
operation to be changed to 375 Hz. For some type of the truck. Special care should be applied
people the 375 Hz pulsing may be more accept- here. The value of this option is used to configure
able than 187.5 Hz pulsing. The 15 kHz used for the drive and pump operation for the truck and if
pump steering functions is unaffected by this set incorrectly could result in erratic truck operation.
option and remains at 15 kHz. When the logics are received out of the parts system
or initially put on a truck on the production line,
Option 26 - Regen Adjustment For Brake Regen option 30 is set to 0 0.0. If the truck is powered up
• Settings: 3/10/5 in RUN mode without first setting this option to
50% TO 100% OF P3 POT IN 10% INCREMENTS some value other than 0 0.0, the truck will shut
This option allows the EAB regen to be adjusted down and an error code 65 will be displayed.
independent of the level of regen set by pot P3. It
is independent as long as the desired EAB regen Option 31 - 34 - Blank
level is lower than that set by P3. This allows the • Settings: 0
user to set the EAB regen softer than normal regen. These options are intentionally left blank.

Option 27 - Pump Transistor Upgrade Option 35 - Bypass Stall Timer

• Settings: 0/2/0 DISABLED/2 200A/2 300A • Settings: 1.5/20/1.5
In an 2EC16 OR 2EC18, option 27 allows the user to
upgrade the pump transistor to a higher capacity
configuration. In a heavy application where the user
is suffering too many pump transistor failures, this
option along with the addition of bigger pump
transistors improves reliability.

19
SENB8604-02

Accessing Programmable Setup

Options
You can access any of the three groups of setup
options directly in order to make programming changes.
To access the First Group (Options 1 - 9):
1. Place the DIAG/RUN/SETUP switch in SETUP.
2. Turn the key switch ON.
The display will show the value of Option 1
(APP-[ ] 01, where [ ] = the selected application.).
To access the Second Group (Options 10 - 27):
1. Place the DIAG/RUN/SETUP switch in SETUP.
2. Pull back on and hold the LIFT and TILT levers
and turn the key switch ON.
The display will show the value of Option 10.
To access the Third Group (Options 28 - 35):
1. Place the DIAG/RUN/SETUP switch in SETUP.
2. Pull back on and hold the LIFT, TILT, and AUX 1
levers and turn the key switch ON.
The display will show the value of Option 28.
Changing Programmable Setup
Options
1. Set Park Brake.
2. Turn key off.
3. Open door (panel).
4. Remove Logic Cover.
5. Place DRS switch in Setup.
6. Plug in battery (if unplugged).
7. Turn on key.
8. Move the directional lever from neutral to forward
or reverse and back to neutral. You have now
increased or decreased the setting value.
9. Move the DRS switch back to Run (center). You
will see triple bars on the display. Triple bars tell
you that the value selected has been stored in
memory.
10. Toggle DRS switch from Setup to Run and then
back to Setup to change to another option.
11. Change value with Forward and Reverse lever.

20
 SENB8604-02

Programming Setup Option 1 Application A - Factory

Option 1 allows you to set the truck to one of five pre- Application b - Hi-Performance
defined modes of operation, according to how your Application C - Economy
truck is used. It changes the truck travel speed, accel-
eration rate, and hydraulic pump speeds. The modes Application d - Long-Travel
(applications) are: Application E - Dock
The modes are defined by the values of options 2, 3, 4,
7, 8, 26, and 28. The following table gives the values
for these options as they correspond to each mode.

OPTION 1 MODES / VALUES

Truck Mode Value of Option
2 3 4 7 8 26 28

APP-A
(FACTORY) 5 8 3 16 10 5 0

APP-b
(HI-PERF) 6 10 6 20 16 5 0
APP-C
(ECONOMY) 5 8 2 20 1 5 1

APP-d
(Long-travel) 5 8 3 20 4 5 0

APP-E
(DOCK) 5 8 4 16 8 10 0

NOTES:
1. Option 28 (EE Mode) is controlled by Option 1 3. You can toggle past Option 1 without resetting it
only if Option 28 is set to 0 or 1. If it is set to 2 by to the preset values, even if any of the values have
the user, Option 1 will not change this value, been modified, by not changing the mode in the
which represents a fully EE’d truck. hour meter area.
2. If the option number is flashing when you first
access the option, this means that one of the
effected values has been changed from its preset
value (the value in the table). Probably one of the
values was modified to further customize opera-
tion of the truck.

Option 1 Applications

21
SENB8604-02

Programming Setup Options Activating Default Settings

(Other than Option 1) Options 1 -27 can be set to their factory default values
by the following procedure.
1. Access the option you want to change, using the
appropriate method described in the previous NOTE: Options 28 - 35 do not reset to default values
section, “Accessing Programmable Setup with this method. Each of these options must be reset
Options.” individually.
2. Change the value: 1. Place the DIAG/RUN/SETUP switch in the
• To increase the value of the option, move the SETUP position.
direction lever to FORWARD, then back to
NEUTRAL. 2. Place the direction lever in REVERSE.
• To decrease the value of the option, move the 3. Make sure the seat switch is OPEN (no operator
direction lever to REVERSE, then back to on the seat).
NEUTRAL.
4. Hold down the accelerator and turn ON the key
3. To move to the next option: switch.
• Move the DIAG/RUN/SETUP switch from
SETUP to RUN, then back to SETUP. The 5. Watch for flashing “donE” on the display. This
option number displayed will increment to the indicates that Options 1-27 have been set to
next number. their factory default values.
• New values are locked in each time you move 6. Turn the key switch to OFF.
the DIAG/RUN/SETUP switch from SETUP to
RUN. 7. Return the DIAG/RUN/SETUP switch to the
After programming any option(s), test the lift truck to normal operation mode (RUN).
be sure that its operation is correct.
Programming the Clock
1. Turn key ON.
2. Push and hold down left orange button for
approximately 5 seconds or until the minutes
area of the clock starts to flash. Release button.
3. Push the right orange button to advance the
minutes of the clock.
4. Press and release the left orange button. The
hours section of the clock will start to flash.
5. Push the right orange button to advance the
hours of the clock.
6. When finished setting the clock, press and
release left orange button.

22
 SENB8604-02

Operational Circuit Elements

Logic Unit
The Logic Unit (logics) has one printed circuit board
contained in a vertical sheet metal box on the control
panel. Most of the circuitry on the board conditions
voltage signals into and out of the microprocessor.
Software in the microprocessor controls the logics
outputs for power components in the pump system,
traction system, contactor coils, and display. Access to
the board is provided by two lock screws, which allow
the cover to be removed.

Logic Board

A jumper should be installed on one of the jumper

blocks according to truck battery voltage:
J1 = 36 volts
J2 = 48 volts
J3 = 72 volts
J4 = 80 volts

23
SENB8604-02

Vehicle Monitoring System Battery Discharge Indicator

Display Unit This liquid crystal display (LCD) uses bars and a bat-
tery symbol to indicate the level of battery discharge.
The vehicle monitoring system display unit is located in When all ten bars appear, the battery is fully charged.
the steering console. It is a self-contained, solid-state As the battery discharges, bars disappear from the dis-
instrument panel with a liquid crystal display (LCD) that play one by one. When only one bar remains on the
has areas for showing: BDI; truck, drive motor, and display, the battery is 70% discharged and the battery
pump motor hours; clock; truck speed; and fault symbol will flash. At 80% discharge, the battery symbol
codes. A separate action light strip below the LCD dis- is solid and no bars appear. The drive and lift (hydraulic)
play uses seven international pictorial symbols to alert motors run at a slower speed. The operator should
the operator of conditions that need attention. complete the current lift operation and travel to the
The display unit interacts with the logics and failure battery replacement or charge area. Replacement of
protection circuits. It functions as a BDI, and provides the discharged battery will reset the BDI, and normal
on-board diagnostic data on the operational condition operation will resume.
of the truck during normal use (“Run-Time” diagnos-
tics) as well diagnostics during troubleshooting (“Self” Hour Meter and Clock
diagnostics). See the topic, “Built-in Diagnostic At start-up, the five LCD numbers and the three sym-
Operation” in the Troubleshooting section of this bols above them indicate service hours for the truck,
manual. for the drive motor, and for the pump motor. Each sym-
bol momentarily lights and its respective hours appear
on the LCD display, in cycle. Periodic maintenance is
3. Speed Fault based on the number of pump hours recorded. After
Code Indicator start up and while the truck is operating, the LCD num-
1. Battery Discharge Indicator (Run-Time and
Self Diagnostics) bers display the time of day.

Speed / Fault Code Indicator

During normal operation, truck speed is indicated by
the two LCD numbers in this area. Either miles per hour
2. Hour Meter 4. Vehicle or kilometers per hour can be chosen for the display by
and Clock Monitoring System pushing the left orange button. The numbers will
Action Lights
change to a fault code if a run-time fault is detected.
The “!” action light will flash on and off while the code
is displayed.

Display Unit
1. Battery Discharge Indicator 2. Hour Meter and Clock
3. Speed/Fault Code Indicator (Run-time and Self- Diagnostics).
4. Action Lights.

24
 SENB8604-02

Action Lights
These symbols glow red when specific problems are
detected. The truck should be stopped and corrective
action taken immediately.

3 4
2 5 6 7
1

Action Lights

1. Service Reminder - The wrench symbol lights

when it is time for periodic maintenance.
Maintenance intervals are programmable. See
the topic, “Programmable Setup Options,”
Option 9.
2. Brush Wear Indicator - The motor symbol lights
if the drive or pump motor brushes need
service. Truck operation can be slowed or
stopped. See the topic, “Programmable Setup
Options,” Option 14.
3. Over Temperature - The thermometer symbol
glows if an overtemperature condition develops
in either drive motor, pump motor, or the control
panel. Reduced drive and/or lift performance
can be programmed into the control system.
See the topic, “Programmable Setup Options,”
Options 10 and 11.
4. Battery Charge - The battery symbol flashes if
the battery charge reaches the 70% discharged
level. At 80% discharge, the symbol glows
constantly (no flashing). Reduced drive and/or
lift performance can be programmed. See the
topic, “Programmable Setup Options,” Options
16, 17, 18.
5. Brake Fluid Level - The brake fluid symbol
flashes if the brake fluid reaches a predeter-
mined low level.
6. Park Brake - The park brake symbol flashes
when the park brake is applied.
7. Fault Detection - At start-up and during truck
operation, drive and pump circuits are moni-
tored for failures.If a fault is detected, the truck
shuts down and cannot be operated until the
cause of the fault is repaired.The fault symbol
will flash and a fault code number will appear in
the Speed/Fault Code Indicator.

25
SENB8604-02

Run-Time Diagnostics DISPLAY = 11 - Drive armature transistor’s emitter low

when not expected
The MicroCommand II Control System controls and Components Involved: T1D and/or T2D
monitors all the electrical and hydraulic operations of Location: Panel
the lift truck. An important part of its job is to detect Cause: A code 11 results when the processor
problems and signal the operator or maintenance per- senses the drive armature transistor emitter
son to take corrective action. Run-time diagnostics being low when it should be high. This error is
function during truck operation. detected during the Close Line Contactor
During truck start-up or operation, if the logics detects Routine (CLOSLC).
a problem, a diagnostic code will appear in the Response: Truck shuts down and the error code
Speed/Fault Code Indicator instead of vehicle speed. is displayed.
The “!” symbol flashes in the action light strip at the
same time the code is displayed. The codes indicate
an improper operating sequence or a defect in the DISPLAY = 15 - D6D anode low when not expected
truck electrical system. • REGEN-EQUIPPED PANELS
Components Involved: D6D, Regen Contactor,
Run-time diagnostics cover the following areas of truck Sense Wire
operation and protection: Location: Panel
• Truck, drive motor, and pump motor hours Cause: A code 15 results when the processor
senses the D6D anode low when it should be
• Service reminder hours high. This error is detected during the first
• Motor brush wear 50mS of regen. This check prevents a regen
contactor that is welded shut from causing the
• Stall protection truck to act unpredictably. It is also possible
• Overtemperature protection of the drive motor, that this error is caused by a broken wire.
pump motor, and the control panel. Response: Truck shuts down and the error code
is displayed.
• Brake fluid level
• PLUG-ONLY PANELS
Listed below are all the possible Run-time error codes, Components Involved: Sense Wire
the components involved and their location (if applica- Location: Panel
ble), the cause of the error code, and the truck Cause: A code 15 results when the processor
response to the problem. Also see the “Troubleshooting senses the D6D sense wire is low. Since this
Problem List” and the troubleshooting flow charts in truck lacks regen, this sense wire is perma-
the Testing and Adjusting section of this manual. nently connected +BAT. If this wire is sensed
low it means that the wire is broken or the
truck size and type have been set to indicate
DISPLAY = 10 - Drive armature transistor emitter high
that the truck is equipped with regen when it
when not expected
really isn’t. This error is sense during the Close
Components Involved: T1D and/or T2D Line Contactor Routine (CLOSLC) and anytime
Location: Panel the regen contactor is closed.
Cause: A code 10 results when the processor Response: Truck shuts down and the error code
senses the drive armature transistor emitter is displayed.
being high when it should be low. This error is
detected during the Close Line Contactor
Routine (CLOSLC) and anytime the line
contactor is in.
Response: Truck shuts down and the error code
is displayed.

26
 SENB8604-02

DISPLAY = 16 - D6D anode high when not expected DISPLAY = 20 - Drive stall timer failure
REGEN-EQUIPPED PANELS Components Involved:
Components Involved: D6D, Regen Contactor, Location: Logics Panel
Sense Wire Cause: A code 20 occurs when the processor
Location: Panel senses that the drive motor has been drawing
Cause: A code 16 results when the processor too much current for too long. The time before
senses the D6D anode high when it should be the failure occurs will be dependent on the
low. It can be caused when the truck type and level of current being drawn. The more the
size are set to indicate that it is a plug-only overload, the shorter the time before a failure.
truck when it isn’t. It can also be caused by a This error is detected anytime the drive motor
bad regen contactor or logic. is being driven. The stall timer failure timer can
Response: Truck shuts down and the error code be set in setup mode. See the topic,
is displayed. “Programmable Setup Option,” option 12, in
this section of the manual.
PLUG-ONLY PANELS
Response: Truck shuts down and the error code
Components Involved: Sense Wire
is displayed.
Location: Panel
Cause: This error is not used on plug-only panels DISPLAY = 21 - Drive current sensor not operating
because the sense wire is permanently tied to Components Involved: E361 (Current Sensor)
+BAT and therefore should always be high. Location: Panel
Cause: A code 21 occurs when the processor
DISPLAY = 18 - Drive shunt field transistor’s drain is
senses a zero reading that is outside of the
high when not expected
allowed bounds. This is an indication that the
Components Involved: T371
sensor is not working correctly or has failed.
Location: Drive Driver Board
This error is detected anytime the directional
Cause: A code 18 occurs when the processor
contactors are open and the truck is in neutral.
senses the drive SF collector being high when
Response: Truck shuts down and the error code
it should be low. This error is detected during
is displayed.
the Close Line Contactor Routine (CLOSLC).
Response: Truck shuts down and the error code DISPLAY = 24 - Drive output overcurrent fault
is displayed. Cause: A code 24 occurs when the processor
senses that the output driver(Q109) is going
DISPLAY = 19 - Drive shunt field transistor’s drain is
into a current limit situation.
low when not expected
Response: Truck shuts down and the error code
Components Involved: T371
is displayed.
Location: Drive Driver Board
Cause: A code 19 occurs when the processor DISPLAY = 25 - Accelerator fault low
senses the drive SF collector being low when Cause: A code 25 occurs when the processor
it should be high. This error is detected during senses that the pulse width modulation (PWM)
the Close Line Contactor Routine (CLOSLC). voltage from the accelerator is too low. This
Response: Truck shuts down and the error code error is detected at all times.
is displayed. Response: Truck shuts down and the error code
is displayed.

27
SENB8604-02

DISPLAY = 26 - Accelerator fault high DISPLAY = 33 - Combination of 31 and 32

Cause: A code 26 occurs when the processor Cause: A code 33 occurs when the processor
senses that the pulse width modulation (PWM) senses that the pump armature transistor
voltage from the accelerator is too high. This emitter is low when it should be high while
error is detected at all times. testing the B and B0 terminals. This error is
Response: Truck shuts down and the error code detected during the Close Line Contactor
is displayed. Routine (CLOSLC).
Response: Truck shuts down and the error code
DISPLAY = 29 - Speed sensor failure
is displayed.
Cause: A code 29 occurs when the processor
senses that the speed sensor is not working DISPLAY = 38 - Pump shunt field transistor’s drain is
correctly. high when not expected
Response: Truck shuts down and the error code Components Involved: T351
is displayed. Location: Drive Driver Board
Cause: A code 38 occurs when the processor
DISPLAY = 30 - Pump armature transistor’s emitter is
detects the pump SF transistor collector high
high when not expected
when it should be low. This error is detected
Components Involved: T1P and/or T2P
during the Close Line Contactor Routine
Location: Panel
(CLOSLC).
Cause: A code 30 occurs when the processor
Response: Truck shuts down and the error code
senses that the pump armature transistor emit-
is displayed.
ter is high when it should be low. This error is
detected during the Close Line Contactor DISPLAY = 39 - Pump shunt field transistor’s drain is
Routine (CLOSLC) and any time the line con- low when not expected
tactor is in. Components Involved: T351
Response: Truck shuts down and the error code Location: Drive Driver Board
is displayed. Cause: A code 39 occurs when the processor
detects the pump SF transistor collector low
DISPLAY = 31 - Pump armature transistor’s emitter is
when it should be high. This error is detected
low when not expected while driving B terminal
during the Close Line Contactor Routine
Components Involved: T1P and/or T2P
(CLOSLC).
Location: Panel
Response: Truck shuts down and the error code
Cause: A code 31 occurs when the processor
is displayed.
senses that the pump armature transistor
emitter is low when it should be high while DISPLAY = 40 - Pump stall timer failure
driving the B terminal of the transistor(s). This Cause: A code 40 occurs when the processor
error is detected during the Close Line senses that the pump motor has been
Contactor Routine (CLOSLC). drawing too much current for too long. This
Response: Truck shuts down and the error code error is detected any time the pump motor is
is displayed. being driven.
Response: Truck shuts down and the error code
DISPLAY = 32 - Pump armature transistor’s emitter is
is displayed.
low when not expected while driving b0 terminal
Components Involved: T1P and/or T2P DISPLAY = 41 - Pump current shunt not operating
Location: Panel Components Involved: Pump Shunt, Wires #29
Cause: A code 32 occurs when the processor and 119
senses that the pump armature transistor Location: Panel
emitter is low when it should be high while Cause: A code 41 occurs when the processor
driving the B0 terminal of the transistor(s). This senses that the pump shunt is not registering
error is detected during the Close Line current when it should be.
Contactor Routine (CLOSLC). Response: Truck shuts down and the error code
Response: Truck shuts down and the error code is displayed.
is displayed.

28
 SENB8604-02

DISPLAY = 44 - Pump output overcurrent fault DISPLAY = 63 - Frame Fault Negative voltage (nonactive)
Cause: A code 44 occurs when the processor Cause: Connection between the lift truck
senses that one or more of the output drivers frame and a negative voltage source.
(Q106 - Q108) are going into a current limit Response: Truck shuts down and error code
situation. is displayed.
Response: Truck shuts down and the error code
DISPLAY = 65 - Truck size not initialized
is displayed.
Cause: A code 65 occurs when the truck is
DISPLAY = 50 - Combination of 10 and 30 powered up in RUN mode with option 30
Cause: Combination of 10 and 30. (Truck size and type) equal to 0 0.0.
Response: Truck shuts down and the error code Response: Truck shuts down and the error code
is displayed. is displayed.
DISPLAY = 51 - Combination of 11, 31, and 32 DISPLAY = 66 - Watchdog timer failure
Cause: Combination of 11 and 31. Components Involved: Logic Card
Response: Truck shuts down and the error code Location: Panel
is displayed. Cause: A code 66 occurs when the logic senses
that its watchdog timer is not functioning.
DISPLAY = 60 - Serial communication fault
Because this circuit monitors the processor
Cause: A code 60 occurs when the serial
proper operation it must always be functional.
communication system fails to communicate a
Response: Truck shuts down and the error code
message in a given amount of time between
is displayed.
the logics and display.
Response: Truck shuts down and the error code DISPLAY = 67 - Battery volts too low
is displayed. Cause: A code 68 occurs when the processor
senses that the battery volts are too low for
DISPLAY = 61 - EEPROM error
the battery voltage chosen by the jumper.
Cause: A code 61 occurs when the processor
24 > 36/48V BATTERY
cannot program a location correctly, or when
60 > 72/80V BATTERY
reading an EEPROM value and its comple-
Response: Truck shuts down and the error code
ment, they don’t agree.
is displayed.
Response: Truck shuts down and the error code
is displayed. DISPLAY = 69 - Battery volts too high
Cause: A code 69 occurs when the processor
DISPLAY = 62 - Frame Fault positive voltage (nonactive)
senses that the battery volts are too high for
Cause: Connection between the lift truck
the battery voltage chosen by the jumper.
frame and a positive voltage source.
36/48V BATTERY > 60
Response: Truck shuts down and the error code
Response: Truck shuts down and the error code
is displayed.
is displayed.

29
SENB8604-02

Chat Mode Pedal Position Duty Cycle (%) Voltage on P1-15

If the seat switch is closed, key switch turned ON, and 0 10.1 12.3
the direction lever is left in NEUTRAL with no other 1 17.6 11.2
operator requests, the line contactor will deactivate
after approximately five seconds. The lift truck will 2 22.6 10.6
remain in this condition until the operator activates the 3 27.6 9.9
direction switch, accelerator pedal, or a control valve 4 32.6 9.2
lever. The line contactor then reactivates, and the truck
5 37.6 8.5
is ready for normal operation.
6 42.6 7.8
Contactors 7 47.6 7.2
The control panel is equipped with 36/48 and 72/80 8 52.6 6.5
volt contactors. The logics will control the “effective
voltage” supplied to the coils. When a contactor is first 9 57.6 5.8
activated, full battery voltage is applied to the coil. 10 62.6 5.1
After the contact tips have closed, the logics will pulse 11 67.6 4.4
the coil to reduce the voltage across the coil to
12 72.6 3.8
between 15 and 35 volts.
13 77.6 3.1
Accelerator Control 14 82.6 2.4
The EP16 family MicroCommand II accelerator uses a 15 87.6 1.7
single wire to communicate pedal position to the log-
ics. The accelerator uses a three-wire connector: As shown, the duty cycle is never 0% or 100% during
Pin 1 - BAT- (Wire #1) normal operation. This means that if you measure 0V or
Pin 2 - Switched Positive (Wire #4) 15V at the input to the logics, something is not working
Pin 3 - Signal Wire (Wire #8) correctly.
The accelerator uses a pulse width modulated (PWM)
signal to communicate the position of the pedal to the
logics. This is very similar to the way the transistors
control the drive and pump motors. The accelerator
changes the duty cycle of the PWM signal to indicate
different positions. The accelerator output is simply a
switch to ground. The switch is turned on and off at a
rate of 500 Hz or 500 times a second. One on/off cycle
is called a period. The on time of the switch compared SIGNAL VANE
RECEIVER
to the period is the duty cycle. In the chart below, it is
shown as a percentage, where 0% means that the SIGNAL
switch never turns on, 50% means the switch is on half GENERATOR
the time, and 100% means the switch is on all of the
time. The logic input for the accelerator is simply a
resistor pulled up to +15V. When the accelerator switch
is on, the resistor pulls this input low; when the accel-
erator switch is off, the resistor pulls this input high.
Additional circuitry in the logics converts this on/off
wave form to a voltage that the logics can read and
convert back to a position. The duty cycles for the
accelerator as are follows:
OPTICAL SWITCH

B75533P1

30
 SENB8604-02

Circuits
Accessory Circuits
Horn Circuit
The horn will operate when the battery is connected
and the horn button is pushed. Current flows from bat-
tery positive through the lights’ fuse, horn button and
horn, back to battery negative.

DC-DC Converter
The DC-DC Converter changes the lift truck battery volt-
age to 12 volts. This 12 volts is used to power acces-
sories such as floodlights, brake/side lights, and horn.
The positive of the 12 volt output is common to the pos-
itive of the battery voltage. The negative of the 12 volt
output is pulsed to maintain a steady 12 volt supply.
The 12 volt output of the converter is protected against
short circuits and overloading by an internal 15 amp
current limit circuit. A fuse on the converter protects it
from reverse connection to battery voltage.

97812-15600

NOTICE: Do not connect the 12 volt negative output

of the DC-DC converter to battery negative. Damage
to system components could occur.

31
SENB8604-02

Drive Circuit Depressing the accelerator pedal will cause the accel-
erator voltage on P1-15 to change as explained under
Control Circuit Accelerator Control. The logics detects the voltage
change at P1-15, activates the correct direction con-
With the actuation circuit complete, the logics supplies tactor, regen contactor (if used) and starts pulsing the
a HIGH voltage (15 volts) to the direction switch at P1- drive power transistors.
9 and P1-10. A HIGH voltage is also supplied to the
accelerator control at P1-15. Battery voltage is sup- With the forward direction selected, current flows from
plied to the accelerator at P9-B. the logics P3-18 through the forward direction and
regen contactor coils (if used) to logics P3-12 and P3-
Selecting a direction will change the voltage from HIGH 14 back to battery negative. The forward and regen
to LOW on P1-10 for forward or P1-9 for reverse. contact tips close.

3
3
LIGHTS FUSE 15A
34
P12-13
KEY FUSE 10A 3 HORN BUTTON
P12-11 P12-12 3 P5-3 P46-2 4 P46-1
R319 R320 KEY SWITCH
P3-18 P5-4 4

P3-4 P5-12 12 P6-4 P6-2 4

DISPLAY
46

34 P3-5 P5-16 16 P6-3 P6-1 1

P2-12 LIFT LIMIT SW
P3-3 SEAT OPERATED BRAKE SW
P1-14 127 P5-21 P60-C P60-A
100 1 +
P2-13
SEAT SWITCH 1
P1-13 P5-7 7 1 HORN
2
PUMP MOTOR THERMOSTAT -
P3-2 77 P5-25 1

P3-1 76 P5-24 1
DRIVE MOTOR THERMOSTAT SERVICE BRAKE SWITCH 3
P1-12 P5-23 113 P40-C P40-B 1

P1-11 P5-19 91 1
PARK BRAKE SW BRAKE FLUID SWITCH
P2-20 P5-22 106 P33-2 P33-1

FWD
P1-10 P5-14 14 P7-B 4
DIR SW P7-A 1
34 REV
P1-9 P5-15 15 P7-C
39 P3-17
LINE COIL
XY 26 P3-9 FWD
P61-2
LIFT COIL P61-1 1
X Y 30 P3-10 FOOT DIR SW
REV
BYPASS COIL P38-8 P61-3
LOGICS

XY 35 P3-11
FWD COIL
P1-1 P5-13 13 P13-5 1
XY 20 P3-12
REV COIL LIFT 1 SW
XY 19 P3-13 P1-2 P5-27 81 P13-6 1 4
REGEN COIL LIFT 2 SW
XY 75 P3-14
3 P1-3 P5-34 89 P13-2 1 P32-3 1

38 P3-16 TILT SW
P32-4 3
LINE FUSE P1-4 P5-33 88 P13-3 1
2 TO 3 TON AUX 1 SW 4
36/48 VOLT
675 AMP P1-5 P5-32 87 P13-4 1 P13-1
600 AMP
1TON AUX 2 SW
P1-6 P5-26 78 P24-2 P24-1 1 1
LINE TWISTED PAIR TWISTED PAIR
CTR PRESSURE SWITCH
P1-19 116 P5-31 P52-2
SPEED
SENSOR
P1-18 115 P5-30 P52-1 SWITCH 1 1 4 1
BATTERY
36/48 VOLT P1-15 8 P5-8 P9-C P9-A
OR P9-B
72/80 VOLT ACCEL
CONTROL
P3-21

P1-21
P3-20
P2-21

P5-36

P5-37
P5-2

P5-1

2EC1513

32
 SENB8604-02

Drive Circuit controlled separately from the pump motor circuit by

the MicroCommand II Control System.
Power Circuit The logics generates an optional 375Hz or 187.5Hz
NOTE: Shaded lines illustrate current flow in the pulsing signal on P2-5. This is faster than can be seen
circuit diagrams. Other circuits can be activated at on a voltmeter and must be viewed with an oscillo-
the same time, but each one is shown separately to scope. When this signal is low, it indicates the power
illustrate current flow in each individual circuit. transistors T1D and T2D should be on. When this signal
is high, it indicates they should be off. When P2-5 goes
The high amperage current that provides the power low, current flows from Battery positive through the
and torque necessary to drive the lift truck flows emitter/base junction of T314 and T315, through R-312,
in this circuit. The speed of the drive motor is through P2-5 to Battery Negative.

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) REGEN COIL
DRIVE MOTOR
75 P3-14
D6D

XY
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR

92
96

2EC1503

33
SENB8604-02

Power Transistors The percent “on-time” of the voltage at logics P2-5 is

also the percent “on-time” of the power transistors. As
When the current flows through the base emitter junc- the “on-time” increases, the average voltage applied to
tion of T314 and T315, this turns the transistors ON. the drive motor increases, which increases the speed of
the lift truck. The percent “on-time” out of the logics is
When T314 and T315 are ON, current flows through determined by how far the accelerator is depressed.
T314,T315 emitter/collector into the base of the drive
power transistors T1D and T2D, causing them to turn At the same time the logics is pulsing the drive motor
ON. With the power transistors ON, high amperage circuit, a constant voltage (about 12V) is being supplied
motor current can flow through them, the motor field, on P2-1 to the gate of T371, turning it 100% ON. With
forward contact tips, motor armature, forward contact T371 ON, current can flow through the drive shunt field
tips, current sensor, and regen contact tips back to bat- fuse, drive shunt field and T371 back to battery nega-
tery negative. When T314 and T315 are OFF, the drive tive. When the drive shunt field is ON 100% at maxi-
power transistors are OFF. mum strength, it adds to the motor torque.

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) REGEN COIL
DRIVE MOTOR
75 P3-14
D6D

XY
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1504

34
 SENB8604-02

When the drive power transistors (T1D and T2D) are

ON, battery current flows through the field windings of
the drive motor, and a magnetic field is created around
the windings. When the power transistors are turned
OFF, battery current through the windings stops, and
the magnetic field collapses. The collapsing magnetic
field induces current, which is used to power the drive
motor while the power transistors are OFF (during puls-
ing). Induced current flows from the field windings
through the forward contact tips, armature, forward
contact tips, current sensor regen contact tips and
diode D4D back to the field windings. Because of this,
the average drive motor armature current will be
greater than the average battery current. The drive
shunt field remains activated during flyback.
Average Current Flow

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) REGEN COIL
DRIVE MOTOR
75 P3-14
D6D

XY
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1505

35
SENB8604-02

Electrical Braking
(Regenerative and Plugging)
Electrical braking permits the lift truck operator to slow,
stop, and change the direction of travel electrically
without having to use the service brake. This action
allows for smooth shuttle operation while saving wear
on the service brakes.
Trucks equipped with regenerative braking (“regen”)
use regenerative power to bring the truck to a stop.
Trucks not equipped with regen use plugging to bring
the truck to a stop. Plugging is the standard form of
electrical braking on 2EC15/18 trucks, although regen
can be added as an option. Regen is the standard
electrical braking on 2EC20-30 trucks.
Regen applies when armature generated current is
forced to flow backwards through the battery. This sys-
tem has much better braking characteristics than “plug
only” systems. The braking energy is used to charge
the battery momentarily, reduce heat build-up in the
drive motor, and extend motor brush life.

36
 SENB8604-02

Regenerative Brakes: Braking Circuit Battery current through the drive shunt field maintains
2EC20-30 Standard Configuration) the magnetic field necessary for the motor rotation to
generate a voltage across the armature.
Regen electrical braking begins when the operator
selects a direction opposite the truck’s motion while The generated voltage produces a current that flows
keeping the accelerator depressed. The logics will through the armature, through the direction contactor
deactivate the regen and bypass contactors (if activat- tips, current sensor, regen diode D6D, power transis-
ed), turn the drive shunt field ON (if it was OFF), and tors, motor series field, direction contactor tips, and
change the direction contactor to the new direction back through the armature. This generated current
selected. The logics will pulse the power transistors at energizes the drive motor series field, which tries to
a slow rate. turn the armature opposite the rotation caused by truck
motion. This brakes the truck electrically. The logics
When the drive power transistors (T1D and T2D) are controls the power transistor pulse rate to keep the
ON with the drive shunt field energized and the drive current below a preset level as monitored by the cur-
motor turning opposite the direction selected, the drive rent sensor. Refer to the Testing and Adjusting section
motor begins to act like a generator. of this manual for proper setup procedures.

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY 19 P3-13
E2 A1 A2
(F2) REGEN COIL
DRIVE MOTOR
75 P3-14
D6D

XY
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1506

37
SENB8604-02

When current peaks at its preset value, the logics will As electrical braking slows the truck, the motor gener-
turn OFF the power transistors. The generated current ates less and less current. The logics makes up for the
will flow from the drive motor field and armature, decreasing generated current by increasing the pulse
through the current sensor, D6D, line fuse, line contac- rate of the power transistors.
tor tips, battery, flyback diode D4D back to the drive
motor field. This is the charging cycle for the battery.
When the current decreases, the logics will turn ON the
power transistors, and the cycle starts again.

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM
A1 A2 XY 19 P3-13
E2
(F2) REGEN COIL
DRIVE MOTOR
D6D

XY 75 P3-14
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1507

38
 SENB8604-02

Plugging Circuit The logics monitors this condition through the current
sensor and reactivates the regen contactor. To prevent
When the speed of the truck slows to less than 2kph contactor tip arcing, the electrical braking of the truck
(1.2mph) the drive motor is no longer turning fast is paused while the regen contactor tips close.
enough to generate enough current to charge the battery.

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) REGEN COIL
DRIVE MOTOR
75 P3-14
D6D

XY
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1508

39
SENB8604-02

Plugging Circuit Plugging electrical braking (the standard configuration

for 2EC15 and 2EC18 trucks) begins when the operator
(2EC15/18 Standard Configuration) selects a direction opposite the lift truck’s motion, while
The logics generates a 750Hz pulsing signal on P2-5. keeping the accelerator depressed. The logics will
This is faster than can be seen on a voltmeter and deactivate the bypass contactor if activated and turn off
must be viewed with an oscilloscope. When this signal the drive shunt field. It will change the direction contac-
is low, it indicates the power transistors T1D and T2D tor to the new direction selected. The logics will then
should be on. When this signal is high, it indicates they begin to pulse the drive shunt field. Because the motor
should be off. When P2-5 goes low, current flows from is turning it acts like a generator, and current begins to
BAT+ through the emitter/base junction of T314 and flow through D5D. This causes wire #1 at the logics to
T315, through R312, through P2-5 to BAT-. become more positive than the sensing wire #51 at P2-
17, due to the voltage drop across diode D5D.

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) DRIVE MOTOR
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21
P12-9
P12-10

92
96

2EC1509

40
 SENB8604-02

Drive Motor
The current in the drive motor is monitored and used to duty cycle. When the transistors are ON, battery current
adjust the duty cycle of the drive shunt field to maintain flows through the power transistors, drive motor field,
plugging current. When the duty cycle on the drive direction contactor tips, and current sensor back to
shunt field has reached 100% and the current starts to BAT-. The generated current will flow from the armature
fall below the plugging current limit, the main power through plugging diode D5D, back to the armature.
transistors T1D and T2D are turned on at a very low

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) REGEN COIL
DRIVE MOTOR
D6D

BATTERY
XY 75 P3-14
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1510

41
SENB8604-02

When the power transistors are OFF, flyback current back to the armature. When the truck has come to a
from the collapsing motor field flows through the direc- stop, the armature no longer is turning opposite the
tion contactor tips, armature, direction contactor tips, pulsed direction. The motor stops generating current, D5D
current sensor, and flyback diode D4D back to the no longer conducts, and the logics no longer detects
motor field. This current continues the electrical braking that sensing wire #51 is lower voltage than wire #1.
action. As long as truck momentum is turning the arma-
The logics will switch into drive mode, and normal
ture opposite the pulsed direction, the motor continues
acceleration in the opposite direction starts.
to act as a generator. The generated current flows
through the current sensor, plugging diode D5D, and

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
REGEN COIL
DRIVE MOTOR
D6D

BATTERY
XY 75 P3-14
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1511

42
 SENB8604-02

Current Limit
The logics monitors the current flow through T1D and
T2D and limits this current flow to a preset value. As Current Limit Setting
this current flows through T1D and T2D, the drive
motor and the current sensor, a voltage is created by
Current
the sensor. This voltage is proportional to the current In
flowing through the sensor and will increase or ARM “On” “Off”
decrease as current changes The logics uses this
voltage to monitor the current in the circuit. When the
current has increased too high, the logics decreases Time
the pulse rate to the transistors to prevent current
higher than the preset value. Current In Relation To Time
Current Limit

43
SENB8604-02

Thermal Protection Circuits Hydraulic Pump Motor

If the pump motor overheats, a thermal switch mount-
Control Panel ed in the pump motor housing will open at a predeter-
If the power transistors overheat, heat is transferred to mined temperature. When it opens, voltage at logics
a thermal switch mounted in a common heatsink. The connection P3-2 will go HIGH. The instrument panel
thermal switch will open at a predetermined tempera- will display a “Run Time” diagnostic symbol. To
ture. When it opens, voltage at logics connection P3-3 decrease the amount of current allowed to flow through
will go HIGH (15 volts). The instrument panel will dis- the pump motor, the logics will restrict the hydraulic
play a “Run Time” diagnostic symbol. The logics will pump motor to speed 8. When the hydraulic pump
decrease the current limit setting of the drive system. It motor cools and the thermal switch closes, the truck
will also reduce hydraulic speed 6 and 7 to speed 5. will return to normal operation.
Speeds 8, 9, and 10 are not affected because these
speeds use the pump contactor, which does not add Drive Motor
heat to the panel. If the drive motor overheats, a thermal switch mounted
in the drive motor housing will open at a predetermined
Failure Protection Circuit temperature. When it opens, voltage at logics connec-
If the logics detects an improper voltage at P2-6 wire tion P3-1 will go HIGH. The instrument panel will dis-
#37 (drive circuit), P2-10 wire #45 (pump circuit) P2-2 play a “Run Time” diagnostics symbol.
wire #92 (drive shunt field circuit) or P2-4 wire #71 To decrease the amount of current allowed to flow
(pump shunt field circuit), the line contactor will be through the drive motor, the Logics will restrict the cur-
deactivated and a “Run Time” diagnostic code (display rent limit to 80% of P1 potentiometer and will also
10 through 69) will replace the speedometer indicator. deactivate the bypass contactor. When the drive motor
Once a failure has been detected, the truck must be cools and the thermal switch closes, the truck will
repaired before normal operation can resume. return to normal operation.

44
 SENB8604-02

Bypass Circuit With Shunt Field full battery voltage to the drive motor. If the accelerator
pedal is fully depressed and the logics has pulsed T1D
Activated and T2D up through 90% “on-time”, the logics will acti-
The bypass circuit bypasses T1D and T2D and con- vate the BYPASS CTR in 1 to 4 seconds.
nects the drive motor in series with the battery, applying

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY
101 CTR CTR 102 35 P3-11
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) REGEN COIL
DRIVE MOTOR
75 P3-14
D6D
XY
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR
P12-10

92
96

2EC1512

45
SENB8604-02

Bypass Circuit Without Shunt Field decreases to a preset limit, the logics turns the shunt
field OFF. With the shunt field OFF, both armature current
Activated and motor speed will increase. If the drive motor increases
With the accelerator fully depressed and the bypass above the preset limit (e.g. climbing a ramp or a hill) the
contactor closed, the logics starts to monitor drive logics turns the shunt field back ON. This gives maximum
current and truck speed. When the drive motor current torque to climb ramps or steep grades.

P12-16

R311

THERMOSTAT
Z313

P8-2
T315
T314

CONTROL
46

P12-15
34

R313
P2-12

D311
B B
T1D T2D 32 P3-3

P8-1
B0 B0 100 P2-13
T

R312
P12-14

R316
R315

R317
BYPASS 1
CTR
31
P12-5 1 31 P2-5
1
37 P2-6

P12-3
DRIVE
SHUNT FIELD
FUSE 15 AMP 1 101 P2-14
68 D1 82 P5-28 82 P1-7
(S1) 51 P2-17
102 P2-15
P12-4

D2 51
(S2)
68 39 P3-17
LINE FUSE DU2 LINE COIL

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT
P32-6

LIFT COIL
675 AMP
600 AMP 107 108 X Y 30 P3-10
1 TON BYPASS COIL
FWD REV XY 35 P3-11
101 CTR CTR 102
LINE FWD COIL
CTR PUMP E1 XY 20 P3-12
MOTOR (F1) REV COIL
CIRCUIT ARM XY
E2 A1 A2 19 P3-13
(F2) REGEN COIL
DRIVE MOTOR
75 P3-14
D6D

XY
BATTERY
36/48 VOLT 1 HEAD REV FWD
P32-1
D5D

OR CAP CTR CTR 38 P3-16

72/80 VOLT
D371
D4D

P16-1 2 P3-7
92
P16-2 42 P3-8
D361 T361
P12-7

P16-3 85 P3-6
P2-11
E361

P2-2
R361

P2-1
T371

97
92
Z371

C371

CURRENT 96
96 SENSOR
R371

P3-21
P3-20
P2-21
P1-21

REGEN
P12-9

CTR

92
96

2EC1501

46
 SENB8604-02

Testing and Adjusting To toggle to the next code, cycle the DIAG/RUN/
SETUP switch from DIAG to RUN and back to
DIAG. When you reach the end of the list (or if
Accessing Stored Fault Codes there are no stored codes), the word “DONE” will
appear.
The logics stores the thirty-two faults or warnings that
occurred on the lift truck. This information is useful for To get back to the beginning from the end of the
troubleshooting intermittent faults, determining which list, cycle the DIAG/RUN/SETUP switch from
motor has worn brushes, or which thermal switch over- DIAG to RUN to DIAG again.
heated. The stored information can also be useful in
determining the application in which the truck is being To clear the fault code memory, cycle the DIAG/
used. Example: pump motor thermal indication has RUN/SETUP switch from DIAG to SETUP, then
been ON; could mean that the truck is used in a heavy wait until the display starts to flash done, then
duty hydraulic application. switch back to DIAG.

The stored faults are accessed by the following proce- The following is a list of possible stored codes:
dure (called a “fault dump”): E1 - DRIVE HOT
1. Start with the key switch OFF. E2 - PUMP HOT
E3 - CONTROLLER HOT
2. Remove the logics cover. B1 - DRIVE BWI
3. Place the DIAG/RUN/SETUP switch to DIAG. B2 - PUMP BWI
4. Turn the key switch ON while pulling back on the AA-HEADCAP FAILURE
LIFT and TILT levers.
NOTE: These fault codes only show up during the
The fault codes will appear on the display, beginning fault code dump.
with the most recent.

47
SENB8604-02

Troubleshooting Troubleshooting Checklist

The following Troubleshooting Check List is an aid in 1. Perform Preparations Tests and Checks.
troubleshooting MicroCommand II lift trucks. The trou- 2. Correct any display problems and “Run Time”
ble-shooting checklist, “Run Time” diagnostic indica- diagnostic faults.
tions, “Self” diagnostic tests, problem list and problem
3. Correct the “Self” diagnostic faults.
flow charts will assist in:
4. Perform Operational Checks.
1. Defining the problem and verifying that a problem
exists. 5. Correct “Other Problems” in the Troubleshooting
Problem List.
2. Performing the checks in a logical order.
6. Perform Operational Checks to verify repairs.
3. Making the necessary repairs.
4. Verifying that the problem has been resolved.

! WARNING
The lift truck can move suddenly. Battery voltage
and high amperage are present. Injury to personnel
or damage to the lift truck is possible. Safely lift both
drive wheels off the floor. Put blocks of wood under
the frame so the drive wheels are free to turn. During
any test or operation check, keep away from drive
wheels. Before any contact with the control panel is
made, disconnect the battery and discharge HEAD
CAP. Rings, watches, and other metallic objects
should be removed from hands and arms when trou-
bleshooting the MicroCommand II Control System.
NOTICE: Damage can be caused to the test equip-
ment. Make resistance and continuity checks only
after the battery is disconnected.
NOTICE: Damage can be caused to the control
panel. Do not use steam or solvent to clean the
controls. Use pressure from an air hose with a
maximum pressure of 205kPa (30 psi) to clean the
control panel when necessary. Make sure the air
pressure supply is equipped with a water filter.
NOTICE: Damage can be caused to the control
panel. Do not switch the direction lever from one
direction to the other (plug the lift truck) when
the drive wheels are off the ground and in rotation
at full speed.

48
 SENB8604-02

Preparation Tests and Checks Cell Voltage Test

With the truck powered up and the power steering
Battery Tests motor running, measure the voltage at each cell.
A weak battery can cause or contribute to problems in Normal voltage should be between 1.95V and 2.12V
the MicroCommand II control and power circuits. Verify per cell. If the voltage on each cell is below 1.95, the
the battery is good before investigating other possibilities. battery must be charged or repaired before continuing
to troubleshoot.
1. Verify proper polarity at the battery connector
and the MicroCommand II control panel. Positive NOTE: The indication between cells should not differ
cable should be at the line contactor and nega- more than 0.05 volts. If it does, the battery must
tive at the negative standoff or regen contactor. have an equalizing charge or be repaired.
2. If the lift truck is operational, perform a Hydrometer Test
battery load test.
Test each cell of the battery with a Battery Hydrometer.
3. If the truck is not operational and the battery is If the specific gravity indication is below 1.140, the
suspected, perform a cell voltage or specific battery must be charged. The battery is fully charged if
gravity test. the indication is 1.265 to 1.285.

Battery Load Test NOTE: The indication between cells should not differ
more than.020. If it does, the battery needs an
1. Turn the range switch on the multimeter to read equalizing charge or needs to be repaired.
battery voltage.
2. Connect the battery. Battery Maintenance
NOTE: It is important that all batteries be charged
and maintained according to the battery manufac-
turers instructions.
The care and maintenance of batteries is most impor-
tant to maximum battery life and efficient truck opera-
tion. Periodic inspection and service will increase the
life of batteries. Special attention should be given to
the rules that follow:
1. Keep batteries clean at all times. Cleaning will
prevent corrosion, current leakage, and shorts to
chassis. Tighten all vent plugs, wash the battery
with water and a brush, then dry with an air hose.
1 2 It may be necessary to use a baking soda solution
if water alone will not clean the top of the battery.
97C54-00300
2. Add enough water to cover the plates before
3. Connect the multimeter leads between positive(+) charging. This will ensure the proper chemical
cable connection (1), and negative (-) cable reaction over the entire plate surface. After
connection (2). charging is complete, add water until it is about
12.7 mm (.50 in) above the plates. Use distilled
4. In a safe area, operate the hydraulic system,
water or water that has tested free from minerals.
(hold tilt lever to maximum position momentarily)
while reading the voltage indicated on the multi- 3. Charge the battery correctly. A battery should be
meter. discharged to 80% of its capacity, then fully
recharged. It should cool four to eight hours to
5. If the indication is less than 33.1 volts for 36 volt
allow the voltage to stabilize before being put
trucks or 44.2 volts for 48 volt trucks, the battery
back in use. The battery should have an equalizing
needs to be charged or repaired before continuing
charge (an extra three or four hour charge at a
to troubleshoot.
low finish rate) once a month to make sure all
cells are in a fully charged condition. Properly
charged batteries should be identified to prevent
low batteries from being installed in trucks.

49
SENB8604-02

4. Operation with a low battery must be prevented. Visual Checks

Low battery operation may damage the battery
and will cause higher than normal current in the 1. Verify all components and wires are in their proper
electrical system. High current draw due to a low place. Check fuses, components, contactor tips,
battery will damage contactor tips and shorten wires and connections. Verify that they are not
motor brush life. burned, broken, or loose.
5. The battery’s maximum temperature is critical. 2. Verify there is no mechanical binding or interfer-
The electrolyte temperature should never exceed ence in the contactors.
43°C (110° F) either while operating or charging. 3. Visually check the parking brake switch, the
Overcharging a battery will cause overheating service brake switch, hydraulic lift switch, and
and warp the battery plates. Maximum battery accelerator linkage for adjustment or interference
life will result from maintaining 25°C (77°F) problems.
electrolyte temperature. Most of the charging
equipment is fully automatic but should be Resistance To Chassis Checks
checked periodically to assure proper working Resistance between any point in the truck wiring and
order. the chassis should be a minimum of 10,000 ohms or
6. Keep accurate battery records. Regular battery more.
readings should be taken with a battery tester or
Many malfunctions are caused by shorts to chassis.
voltmeter and a written record kept. Specific
Usually, two shorts must exist before a malfunction will
gravity and voltage of each cell should be
occur. But, since batteries can have chassis leakage,
checked and recorded at least once each month.
only one short to chassis in the truck wiring can cause
This inspection should be made after an equaliz-
problems. To prevent problems because of shorts, do
ing charge. Readings should never be taken
the following:
directly after water has been added. Records of
all battery maintenance should be made and filed 1. Disconnect the battery and discharge the
so it will be known which batteries are being HEAD CAP.
abused or wearing out. 2. Measure from the chassis to both sides of the
Repairs should be made immediately, otherwise the line contactor, component connection or wiring
battery may become damaged. Batteries stored in a connection in respect to the lift truck chassis for
discharged condition may be difficult to recharge due a minimum resistance of 10,000 ohms. Any test
to sulfate formation. point with low resistance must have the short to
chassis removed.
3. Always keep batteries clean to minimize current
leakage to the chassis.
4. Routinely clean the brush dust from the motors.
5. Be sure that all attachments, such as horns and
lights, are designed for no chassis connection
(a two-wire system).

Removal Of Shorts To Chassis

When a short is found, it must be cleared even if the
machine has normal operation. It is necessary to narrow
the field of possible problem areas before inspection of
individual wires and components.
When a low resistance circuit is located, it should be
opened at various points. This will permit the shorted
wire or component to be pinpointed for repair or
replacement.

50
 SENB8604-02

Control And Power System Check 5: Reverse Drive Performance

1. Select reverse direction and depress the acceler-
Operational Checks ator slightly. The reverse contactor will activate
All operational checks are to begin with: programmable and the drive wheels will turn in reverse slowly.
features set to the default values, battery connected, 2. Slowly increase the amount of accelerator
directional switch in neutral, drive wheels off the depression. The reverse contactor will remain
ground, and the accelerator and parking brake activated. The drive wheels will turn in reverse
released. and slowly increase in speed.
NOTE: Perform all operational checks before 3. Depress the accelerator fully. The reverse contactor
returning to the Troubleshooting Check List. will remain activated and bypass contactor will
activate. The drive wheels will turn in reverse at
Check 1: Key And Seat Switch full speed.
1. Actuate the key and seat switch. The line contactor
Check 6: Electrical Braking Performance
activates and the hydraulic motor runs. After five
seconds the line contactor deactivates and the NOTICE: Do not perform this check with the lift
motor turns off. truck in bypass mode. Damage to the control panel
can result.
Check 2: Power Steering Performance
1. Turn the steering wheel. The pump motor should 1. Select forward direction and depress the acceler-
provide adequate hydraulic flow for the steering ator to the point just before bypass occurs. While
system. continuing to depress the accelerator, change the
direction switch to reverse. The forward contac-
Check 3: Lift, Tilt, and Auxiliary Performance tor should deactivate and the reverse contactor
should activate. There should be a smooth decel-
1. Slowly pull the lift control lever. The pump motor
eration of forward tire rotation and a smooth
will activate.
acceleration of reverse tire rotation.
2. Pull the lift control lever further and the motor
2. While continuing to depress the accelerator in
speed will increase to the maximum speed.
reverse direction change the direction switch to
3. Slowly pull and push the tilt and auxiliary levers. forward. The reverse contactor should deactivate
The pump motor increases speed with each lever and the forward contactor should activate. There
movement. should be a smooth deceleration of reverse tire
Check 4: Forward Drive Performance rotation and a smooth acceleration of forward tire
rotation.
1. Engage the parking brake. Select forward direc-
tion and depress the accelerator slightly. The for-
ward contactor will not activate and the drive
wheels will not turn. The park brake action light
will be on.
2. Release the parking brake, select forward direc-
tion and depress the accelerator slightly.
Depending upon the setting of Option 13, the
forward contactor may activate and the drive
wheels may turn forward slowly.
3. Slowly increase the amount of accelerator
depression. The forward contactor will remain
activated. The drive wheels will turn forward and
slowly increase in speed.
4. Depress the accelerator fully. The forward
contactor will remain activated and the bypass
contactor will activate. The drive wheels will turn
forward at full speed.

51
SENB8604-02

Built-In Diagnostic Operation Brush Wear Indicator ON - lift truck operation

is normal. See Troubleshooting Problem 5.
The logics and the display provide built-in diagnostic Possible cause, worn brushes on pump and/or
analyzer functions. Numerous diagnostic functions drive motor.
occur while the truck is in operation. These are called
“Run-time” diagnostics. The other diagnostics are Overtemperature Indicator ON - lift truck
called “Self” diagnostics. They are performed when the accelerates slower than normal. See
lift truck is not in operation by using a switch located in Troubleshooting Problems 6, 7, and 8. Fault
the logics. codes E1, E2, or E3 may be stored. Possible
causes, control panel, drive or pump motor
“Run-Time” Diagnostics overtemperature; faulty thermal switch.
(lift truck in Operation) Display = 20 - No lift truck operation.
The diagnostics functions that follow would occur dur- See Troubleshooting Problem 15. Possible cause:
ing normal lift truck operation and are shown on the current limit out of adjustment, Drive Pulsing Stall
LCD display. The speedometer portion of the LCD Timer option, or Bypass option set incorrectly.
display is used to indicate the fault codes.
Display = 60 - No lift truck operation.
There are a total of 31 possible Run-Time fault codes. See Troubleshooting Problem 32. Possible cause,
Listed below are some common codes and their possi- serial communications fault between the display
ble causes, with references to the Troubleshooting and the logics.
Problem list and flow charts found later in this section
of the manual. Refer to that list and the flow charts for Display = 65 - No lift truck operation.
the specific code, and the problem it indicates, that See Troubleshooting Problem 34. Possible cause,
you are trying to troubleshoot. truck size not initialized. (Programmable Setup
option 30).
Display = 68 or 69 - No lift truck operation.
See Troubleshooting Problem 36. Possible cause,
battery volts too low or too high for chosen jumper.

52
 SENB8604-02

“Self” Diagnostics
(Lift Truck Not In Operation) ! WARNING
The “Self” diagnostic procedure should be used to help The lift truck can move suddenly. Injury to personnel
troubleshoot after a problem has occurred. Self or damage to the lift truck is possible. Disconnect
Diagnostics are most useful for finding faulty circuits or the battery and disconnect the line fuse to prevent
components. Complete all the tests before returning to lift truck movement.
the Troubleshooting Check List. 4. Release the park brake to close the park brake
switch.
NOTE: The Self Diagnostics procedure as well as the
LCD display readouts for test pass and fail is printed 5. Loosen the two screws (2) and remove the logics
on a decal located on the inside door to the control cover (3).
panel. Following the procedure on the decal is
recommended.
Before beginning the Self Diagnostics tests, do the
following:
1. Turn the key switch OFF.
2. Disconnect the battery and check the head
capacitors for discharge below 5 volts. If the
head capacitors are not discharged, discharge
them by holding a discharge resistor in place for
20 seconds. See the topic, “Discharging the
Head Capacitor” in the Testing And Adjusting
section of this manual.

C0000 Logics Board

6. Move the switch to the DIAG position. This

2 places the controller in diagnostics when the key
3 2
switch is turned on. If any of the tests that follow
fail [except the line (drive) fuse test where the
display = “dd”], continue through the tests that
remain. Make a note of all failed tests for detailed
troubleshooting.
1
To bypass a failed test and allow the next test to be
performed, move the switch to the RUN position then
back to the DIAG position.

Location of Components
(1) Line fuse. (2) Screws. (3) Logics cover.

3. Disconnect the line fuse (1) to prevent lift truck

movement.

53
SENB8604-02

Circuit Tests Test F: Service Brake Circuit

NOTE: It is not necessary for the park brake to be
Test A: Internal Circuitry released for this test.
Connect the battery and turn the key switch ON. Depress and release the service brake.
Display = “blank” See Troubleshooting Problems Display = 04 Service brake circuit defect.
1, 2, or 3. See Troubleshooting Problem 41.
Display = FF Logics failure. Replace logics. You Display = 05 Service brake switch circuit OK.
may also bypass this failure by toggling the
DIAG/RUN/SETUP switch to RUN and back to Test G: Accelerator Circuit
DIAG.
Fully depress and release the accelerator.
NOTE: This test does not check all the logics
circuits, so the logics may pass this test and Display = 05 Accelerator circuit defect.
still have a failure. See Troubleshooting Problem 42.

Display = dd Line fuse not disconnected or head Display = Flashing 00 Accelerator circuit OK,
capacitors not discharged below 5 volts. ready to perform the accelerator speed test.
Return to Step 2.
Test H: Accelerator Speed Check
Test B: Line (drive) Fuse Out Depress the accelerator again.
This test will take place automatically if Test A is Display shows flashing accelerator position, 00 - 15.
completed successfully. If some speeds are missing, at the beginning or the
Display = 01 Line (drive) fuse is out and head end of travel, for example, then the pedal probably
capacitors are discharged, as they should be f needs to be adjusted. To bypass the flashing speed
or these tests. The 01 display indicates a pass number and proceed to the next test, toggle the
for this test. DIAG/RUN/SETUP switch from DIAG to RUN and
back to DIAG.
Display = dd Line fuse not disconnected or
head capacitors not discharged below 5 volts. Test I: BDI Circuit
Return to Step 2.
This test is performed automatically after the
Test C: Seat Switch Circuit DIAG/RUN/SETUP switch is toggled in the preced-
ing test. The BDI test happens quickly; in fact, if the
Press and release seat to close and open seat BDI is OK, 06 (indicating a pass for Test H) may be
switch. bypassed too quickly to be seen.
Display = 01 Seat switch circuit defect. Move Display = 06 BDI circuit failure.
hand around on seat and press again. If still See Troubleshooting Problem 43.
01, see Troubleshooting Problem 37. Display = 07 BDI circuit OK.
Display = 02 Seat switch circuit OK.

Test D: Direction Switch Circuit

Cycle the direction lever from neutral to reverse to
neutral again and then to forward.
Display = 02 Direction switch circuit defect.
See Troubleshooting Problem 38.
Display = 03 Direction switch circuit OK.

Test E: Park Brake Circuit

Engage and release the park brake.
NOTE: The Park Brake action light may come on.
This does not indicate a problem.
Display = 03 Park brake circuit defect.
See Troubleshooting Problem 40.
Display = 04 Park brake circuit OK.

54
 SENB8604-02

Test J: Lift Switch Circuit Test M: Aux2 Switch Circuit

Pull the lift lever back to maximum and release. NOTE: If AUX2 does not exist on the test truck,
Display = 07 Lift switch circuit defect. bypass by toggling the DIAG/RUN/SETUP switch.
See Troubleshooting Problem 44. Pull the aux2 lever back to maximum and release.
Display = 08 Lift switch circuit OK. Display = 10 Aux1 switch circuit defect.
See Troubleshooting Problem 47.
Test K: Tilt Switch Circuit Display = Flashing 00 Aux2 switch circuit OK.
Pull the tilt lever back to maximum and release.
Display = 08 Tilt switch circuit defect. Test N: Hydraulic Speed Check
See Troubleshooting Problem 45. After a successful aux2 circuit test, the flashing
Display = 09 Tilt switch circuit OK. number in the display can show the speed associated
with each hydraulic function. For example, if you
Test L: Aux1 Switch Circuit pull back on the tilt lever, you will see the tilt speed
on the display. Only one lever should be tested
Pull the aux1 lever back to maximum and release. (pulled back) at a time. Exception: If you are using
Display = 09 Aux1 switch circuit defect. only the lift0 and lift1 switches, you can test them
See Troubleshooting Problem 46. both at the same time. The speed displayed repre-
Display = 10 Aux1 switch circuit OK. sents the second lift speed.
To exit the hydraulic speed check (bypass the flash-
ing 00), toggle the DIAG/RUN/SETUP switch from
DIAG to RUN and back to DIAG.
Display = 11 Ready for the next test.

55
SENB8604-02

Tests “O” Through “T” Test R: Forward Contactor Circuit

The remaining tests check contactor operation. You Move the DIAG/RUN/SETUP switch to RUN.
will toggle the DIAG/RUN/SETUP switch from DIAG Display = 15 and the forward contactor (4) does
to RUN to activate the contactor being tested, then not close. Circuit is defective.
toggle the switch back to DIAG to deactivate it. You See Troubleshooting Problem 50.
must visually observe the contactors for proper Display = 15 and forward contactor (4) closes.
operation during these tests. Forward contactor circuit OK.
Move the DIAG/RUN/SETUP switch to DIAG.
Display = 16 and the forward contactor (4) opens.

Test S: Reverse Contactor Circuit

Move the DIAG/RUN/SETUP switch to RUN.
Display = 16 and the reverse contactor (5) does
not close. Circuit is defective.
See Troubleshooting Problem 50.
Display = 16 and reverse contactor (5) closes.
Reverse contactor circuit OK.
Move the DIAG/RUN/SETUP switch to DIAG. If the
panel does not have regen, the display will =
donE. The self diagnostics are complete for non-
regen (plug only) panels. If the panel has regen,
1 the display = 17 and the reverse contactor (5)
3 4 6
2 5 opens. Go to Test T.
Contactor Locations. Panel with regen is shown.
Plug-only panels will not have regen contactor (6).
Test T: Regen Contactor Circuit
(1) Line contactor. (2) Pump bypass contactor. (3) Drive bypass contactor. Move the DIAG/RUN/SETUP switch to RUN.
(4) Forward contactor. (5) Reverse contactor. (6) Regen contactor. Display = 17 and the regen contactor (6) does
Test O: Line Contactor Circuit not close. Circuit is defective.
Move the DIAG/RUN/SETUP switch to RUN. See Troubleshooting Problem 50.
Display = 12 and the line contactor (1) does not Display = 17 and regen contactor (6) closes.
close. Circuit is defective. Regen contactor circuit OK.
See Troubleshooting Problem 50. Move the DIAG/RUN/SETUP switch to DIAG.
Display = 12 and line contactor (1) closes. Line Display = donE and the regen contactor (6) opens.
contactor circuit OK.
Move the DIAG/RUN/SETUP switch to DIAG.
Display = 13 and the line contactor (1) opens.

Test P: Pump Bypass Contactor Circuit 2

Move the DIAG/RUN/SETUP switch to RUN. 3
Display = 13 and the pump bypass contactor (2)
does not close. Circuit is defective.
See Troubleshooting Problem 50.
Display = 13 and pump bypass contactor (2) 1
closes. Pump bypass contactor circuit OK.
Move the DIAG/RUN/SETUP switch to DIAG.
Display = 14 and the pump bypass contactor (2)
opens.
Location of components: 1.Line Fuse 2.Screws 3.Logics Cover

Test Q: Drive Bypass Contactor Circuit This completes the self-diagnostics tests. The contac-
Move the DIAG/RUN/SETUP switch to RUN. tor tests may be repeated by moving the
Display = 14 and the drive bypass contactor (3) DIAG/RUN/SETUP switch to RUN and back to DIAG.
does not close. Circuit is defective. If you are finished with self diagnostics, do the following:
See Troubleshooting Problem 50. 1. Disconnect the battery and install the line fuse (1).
Display = 14 and drive bypass contactor (3) 2. Move the DIAG/RUN/SETUP switch to the RUN
closes. Drive bypass contactor circuit OK. position.
Move the DIAG/RUN/SETUP switch to DIAG. 3. Install the logics cover (3) and tighten screws (2).
Display = 15 and the drive bypass contactor (3)
opens.
56
 SENB8604-02

Troubleshooting Charts
Problem # Problem Type
Display Problems
1 When seat switch is closed, speedometer area of display goes blank. No lift truck drive or pump motor operation.
2 Display does not work at all. Lift truck operation is normal.
3 Display does not work. No lift truck operation.
4 BDI # does not change with a change in battery voltage.
“Run Time” Diagnostic Problems
5 Brush wear indicator is on.
6 Overtemperature indicator is “ON”, lift truck accelerates slower than normal. Truck goes into bypass.
Pump motor speeds 6 and 7 are reduced. Fault code E3 is stored.
7 Overtemperature indicator is “ON” lift truck accelerates slower than normal. Truck goes into bypass.
Bypass contactor will not close.Pump motor operation normal. Fault code E1 is stored.
8 Overtemperature indicator is ON, lift speed slower than normal. Drive motor operation normal. Fault code E2 is stored.
9 Display = 10: Drive armature transistor fault (high). No lift truck operation.
10 Display = 11: Drive armature transistor fault (low). No lift truck operation.
11 Display = 15: D6D anode fault (low). No lift truck operation. (Trucks with regen).
11A Display = 15: D6D sense wire fault. No lift truck operation.
12 Display = 16: D6D anode fault (high). No lift truck operation.
13 Display = 18: Drive shunt field transistor drain fault (high). No lift truck operation.
14 Display = 19: Drive shunt field transistor drain fault (low). No lift truck operation.
15 Display = 20: Drive stall timer failure. No lift truck operation.
16 Display = 21: Drive current sensor failure. No lift truck operation.
17 Display = 24: Drive output overcurrent fault. No lift truck operation.
18 Display = 25: Accelerator fault (low). No lift truck operation.
19 Display = 26: Accelerator fault (high). No lift truck operation.
20 Display = 29: Speed sensor failure. No lift truck operation.
21 Display = 30: Pump armature transistor emitter fault (high). No lift truck operation.
22 Display = 31: Pump armature transistor emitter fault (low, B terminal). No lift truck operation.
23 Display = 32: Pump armature transistor emitter fault (low, B0 Terminal). No lift truck operation.
24 Display = 33: Combination of F31 and F32. No lift truck operation.
25 Display = 38: Pump shunt field transistor drain fault (high). No lift truck operation.
26 Display = 39: Pump shunt field transistor drain fault (low). No lift truck operation.
27 Display = 40: Pump stall timer failure. No lift truck operation.
28 Display = 41: Pump current shunt failure. No lift truck operation.
29 Display = 44. Pump output overcurrent fault. No lift truck operation.
30 Display = 50: Combination of F10 and F30. No lift truck operation.

57
SENB8604-02

Problem # Problem Type

31 Display = 51: Combination of F11, F31, F32, and F33. No lift truck operation.
32 Display = 60: Serial communications fault. No lift truck operation.
33 Display = 61: EEPROM error. No lift truck operation.
34 Display = 65: Truck size not initialized. No lift truck operation.
35 Display = 66: Watchdog timer failure. No lift truck operation.
36 Display = 68 or 69: Battery volts too low for chosen jumper. No lift truck operation.
“Self” Diagnostic Problems
37 Seat switch circuit defect.
38 Direction switch circuit defect.
39 Foot-operated direction switch defect.
40 Park brake circuit defect.
41 Service brake circuit defect. Note: Must be repaired before moving on!
42 Accelerator circuit defect.
43 BDI circuit defect.
44 Lift switch circuit defect.
45 Tilt switch circuit defect.
46 Aux 1 switch circuit defect.
47 Aux 2 switch circuit defect.
48 Hydraulic speed check.
49 Incorrect contactor operation.
Other Problems
50 Any contactor closes when key switch is closed.
51 Drive motor does not operate or operates with low power or is erratic. Pump system operation normal.
52 Poor acceleration, loss of power on ramps.
53 Lift truck has long electrical braking distance or sudden stop at end of braking cycle. Pump system operation normal.
54 Current limit and/or electrical braking limit adjustment cannot be made.
55 Auxiliary lighting and/or alarm does not function correctly. Lift and drive systems operation normal.
56 Slow steering, but pump motor does turn. Drive and lift systems operation normal.
57 Steering idle speed runs fast. (Pump motor runs at high power steering speed continuously.)
Pump motor runs continuously in neutral (no chat mode).
58 Lift truck speed reduced to 2.0 mph (no code).
59 Display = FFFF.O: Change display.
60 Code H: Hydraulic Switch is closed when key is turned on.
61A & B Code E: Accelerator depressed before key is turned on. Seat Switch open when it should be closed.

Note: Check for shorts to chassis or open wiring at the start of any problem. Use a 6V4042 Wiring Harness Test
Group to find a wire-to-wire short, shorts to chassis, and continuity. Always follow the sequence defined here
using the display and built-in analyzer functions to aid in troubleshooting.

58
 SENB8604-02

PROBLEM 1
Speedometer portion of display works until seat switch is closed, then blank. No lift truck drive or pump motor operation.

POSSIBLE CAUSE
Line contactor defect: line fuse open circuit: wire #34 at P2-12 open circuit: logics defect.

CHECKS
Does the line contactor remain closed?

YES NO
Check voltage at bottom of line fuse with line contactor activated. See problem 49,
Incorrect
Contactor
Battery Voltage Less Than Battery Voltage Operation.

Check voltage at top of line fuse with line contactor activated. Repair or replace line contactor tips
or power connection.

Battery Voltage Less Than Battery

Check voltage at logics connector Voltage
P2-12 (wire #34) on the silver area. Check for possible shorts in
Do not disconnect the logics the power circuit (Head
connector. capacitor, diodes, shorted
cables) and replace line fuses.
If repeat failures occur, check
drive motor current limit and/or
lift truck.
Battery Voltage Less than
Battery Voltage
Replace logics.
Repair open
circuit between
line fuse and
P2-12, wire #34.

59
SENB8604-02

PROBLEM 2
Display does not work at all: lift truck operation normal. If only part of the display works, replace the whole display unit.

POSSIBLE CAUSES
Disconnected display connector P6: open circuit from P6-1 to battery negative: open circuit from key switch to P6-2: defective display unit.

CHECKS
Is display connector P6 connected?

YES NO
Connect multimeter positive lead to P6-2 (wire #4) and negative lead to P6-1 (wire #1.) Connect P6
Measure the voltage. connector to display
unit.
Battery Volts 0 Volts
Replace the display unit. Repair or replace open circuit between key switch and
P6-2 wire (wire #4) or between P6-1 (wire #1) and
battery negative.

60
 SENB8604-02

PROBLEM 3
Display does not work: no lift truck operation.

POSSIBLE CAUSES
Battery polarity not correct on control panel: key fuse open circuit: key switch defect: logics defect: defective display unit.

CHECKS
With battery connected, check control panel battery connections for correct polarity. Positive battery is connected to negative heat sink.

If Correct If Not
Disconnect battery and check key fuse for continuity. Correct

Continuity No Make correction

Check for continuity from key fuse holder to control panel battery positive connection at Continuity to cables.
the line contactor (wire #3). Also check continuity from key fuse to holder to wire #3 Check for
on key switch. shorts and
replace fuse.

Continuity No Continuity
Close key switch. Measure voltage on P3-18 and P6-2. Repair or replace
open circuit.

Battery Voltage Less Than Battery

Voltage
Check continuity from battery
negative to logics P1-21, P2-21, Replace key switch or
P3-21, P3-20, and display P6-1 repair broken wire #4
between key switch and P6-
(wire #1). 2 or key switch and P3-18.

No
Continuity Continuity
Replace logics Repair or
or display unit. replace open
wire.

61
SENB8604-02

PROBLEM 4
Battery Discharge Indicator (BDI) number does not change with a change in battery voltage.

POSSIBLE CAUSES
BDI setting is out of adjustment: BDI jumper positioned incorrectly: defective logics.

CHECKS
Check BDI jumper for proper positioning:
J1 = 36V J2 = 48V J3 = 72V J4 = 80V
Follow BDI adjustment procedure to verify correct BDI settings. (Be sure to cycle key switch between adjustments.)
See the topic “Battery Discharge Indicator (BDI) Adjustment” in the Systems Operation section of this manual.

Cannot Adjust to Specifications

Replace logics.

62
 SENB8604-02

PROBLEM 5
Brush Wear Indicator (BWI) is ON.

POSSIBLE CAUSES
Worn brushes on pump and/or drive motor: display unit defect.

CHECKS
Check the stored fault code area to determine if the indication is for the pump motor or the drive motor.

b2 - Pump Neither b1
b1 - Drive
nor b2
Check drive motor brushes. Check pump motor brushes.
Replace display.
Look OK Worn Look OK Worn
to low Disconnect the pump motor wear
to low
Disconnect the drive motor wear
indicator (wires #107 and #108) at the limit indicator (wires #109 and #110) at the motor. limit
motor. Turn the key switch OFF, then Replace Turn the key switch OFF, then ON. Replace
ON. Check display for BWI. brushes. Check display for BWI. brushes.
Display OK BWI Still ON Display OK BWI Still ON
Check for short Check for continuity Check for Check for continuity from
to battery from wires #109 and short to bat- wires #109 and #110 to
negative #110 to battery tery negative battery negative.
inside the motor. negative. inside the
motor.
Continuity No
Continuity Continuity No
Repair Continuity
shorted Replace Repair shorted
wire. display wire. Replace display
unit. unit.

63
SENB8604-02

PROBLEM 6
Overtemperature indicator ON. Truck accelerates slower than normal. Truck goes into bypass.
Pump motor speeds 6 and 7 are reduced. E3 stored in fault code area.

POSSIBLE CAUSES
Control panel overheated: thermal switch defect: open wiring: logics defect: display unit defect.

CHECKS
Open control panel compartment. Allow truck to cool 15 minutes.

Overtemperature Indicator Still ON Display OK

Check stored fault codes. Verify E3 is present. Control Panel was over-
heated. Resume normal
E3 No E3 operation. If condition
repeats, check the
Check stored fault codes. Verify E3 is present. Replace display unit.
following:
High Low • Current Limit
Calibration
Disconnect the battery. With the control panel at close Replace
• BDI Calibration
to room temperature, disconnect the thermal switch logics.
connector P8. Check continuity of thermal switch. • Operating Cycle for
Should have continuity below 69°C (156°F). excessive ramp
climbing, towing, or
Continuity No
pushing
Check continuity from P3-3 on the Continuity
logics board (silver area) to P8-2 • Brake drag, park
Replace
(wire #46). thermal switch. brake adjustment
Continuity No • Service Brake
Check continuity from Continuity interrupt switch
P8-1 to battery negative Repair or operation.
(wire #1). replace wire
and/or
connector
P3.
Continuity No
Continuity
Repair or
replace Verify
wire. problem
still exists.

64
 SENB8604-02

PROBLEM 7
Overtemperature indicator ON. Truck accelerator slower than normal. Bypass contactor will not close.
Pump motor operation normal. E1 stored in fault code area.

POSSIBLE CAUSES
Drive motor overheated: drive motor thermal switch defect; open wiring; logics defect; display unit defect.

CHECKS
Allow truck to cool 15 minutes.

Overtemperature Indicator Still ON Display OK

Check stored fault codes. Verify E1 is present. Drive motor was over-
heated: resume normal
E1 No E1 operation. If condition
Measure the voltage at P3-1 (wire #76) on the logics board (silver area). repeats, check the
Replace display unit. following:
Scrape coating off board if needed. Do NOT disconnect from logics.
• Current limit
High Low calibration
Disconnect the battery. With the drive motor at close to room Replace • BDI calibration
temperature, disconnect the thermal switch connector P8. Check display
continuity of thermal switch. Should have continuity below • Operating cycle for
69°C (156°F). unit.
excessive ramp
climbing, towing, or
Continuity No Continuity
pushing
Disconnect P3 from the Replace
display unit. Check continuity from P3-1 to thermal switch. • Brake drag, park
battery negative (wire #1). brake adjustment
Continuity No Continuity • Service brake
interrupt switch
Find short to battery Verify
negative in the problem still exists. operation.
harness. Repair or
replace wire.

65
SENB8604-02

PROBLEM 8
Overtemperature indicator ON. Lift speed slower than normal. Drive motor operation normal. E2 stored in fault code area.

POSSIBLE CAUSES
Pump motor overheated: pump motor thermal switch defect; open wiring; logics defect; display unit defect.

CHECKS
Allow truck to cool 15 minutes.

Overtemperature Indicator Still ON Display OK

Check stored fault codes. Verify E2 is present. Pump motor was
over-heated: resume
E2 No E2 normal operation. If
condition repeats, check
Measure the voltage at P3-2 (wire #77) on the logics board (silver area). Replace display unit. the following:
Scrape coating off board if needed. Do NOT disconnect from logics.
• Pump motor brushes
High Low
• BDI calibration
Disconnect the battery. With the pump motor at close to room Replace
temperature, disconnect the thermal switch connector P8. Check • Attachment pressures
logics.
continuity of thermal switch. Should have continuity below
69°C (156°F). • Heavy hydraulic
application.
No Continuity Continuity
Disconnect P3 from the Replace
display unit. Check continuity from P3-1 to thermal switch.
battery negative (wire #1).

No Continuity Continuity
Verify Find short to battery
problem still exists. negative in the
harness. Repair or
replace wire.

66
 SENB8604-02

PROBLEM 9
Display = “10” : (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
Shorted T1D or T2D: Shorted bypass contactor tips: open wiring: failed drive driver board: failed logics.
Slow bypass contactor.

CHECKS
Disconnect the battery: check bypass contactor for welded or shorted tips. Check contactor for free tip movement.

Tips not shorted Tips shorted

Disconnect battery: remove logics cover: check continuity of wire #37 at emitter Repair or replace
bus bar of power transistor to logics P2-6. contactor. Check BDI
Continuity No Continuity adjustment. Check
current limit adjustment.
Check T1D, T2D for failure. Repair or replace wiring. Check bypass dropout
current.
Test OK Failed
Test Drive Driver Board. Replace
failed
compo-
nents.

Test OK Failed
Replace logics.* Replace
drive driver board.*
* = See NOTICE.

NOTICE: Damage to the control panel could Field Failure Notes:

result. To prevent further damage, before
1. Field failures indicate that a traction motor
T1D, T2D, or the drive driver board are
shunt field to series field short may also cause
replaced, complete the following checks.
this code.
1. Check diode D4D for failure.
2. Also, slow bypass contactors.
2. Check diode D5D for failure.
3. Current sensor.
3. Check T1D, T2D for failure.
4. Check drive driver board for failure.
5. Check head capacitors for failure.
6. Check for continuity from emitter bus bar of
power transistors (wire #37) to logics P2-6.
7. Check drive motor for shorts, shorts between
shunt and series field, shorts to frame, and opens.

67
SENB8604-02

PROBLEM 10
Display = “11” : (!) action light flashing: no lift truck operation. Line contactor opens and closes.

POSSIBLE CAUSES
Faulty wire connections: T1D or T2D failed: current limit set too low: failed D4D or D5D: failed drive driver board: failed logics.

CHECKS
Disconnect the following wires. Visually inspect them for burnt or discolored terminals, loose connections, smashed or compressed
connectors, corrosion or foreign material.
Wire #31 at P2-5.
Wire #37 at P2-6 and emitter bus bar of drive power transistors.
Wire #31 and #32 at resistor R312.
Wire #34 from drive driver board to positive heatsink.
Wire #1 from drive driver board to negative heatsink.
Wire #42 from logics P3-8 to current sensor.
Wire #85 from logics P3-6 to current sensor.
Wire #2 from logics P3-7.
Repair any defects, then reconnect the wires.
Display = “11” Display Normal
Check T1D, T2D for failure. Return truck to operation.
Not Failed Failed
Perform Rapid Tune-up procedure for current limit and regen potentiometers. Replace failed transistor.
Display
Display = “11” Normal
Measure voltage at P3-8 (wire #42) with the key switch closed. Recalibrate current
limit, regen current
adjustments to
specifications.*
Voltage = 3.6 tp to 4.0V Any Other
Check continuity from P3-3 on the Voltage *NOTICE: Damage to the control panel could result. To
logics board (silver area) to P8-2 Perform steps 1 prevent further damage, before T1D, T2D, or the drive
(wire #46). through 5 of the driver board are replaced, complete the following
Current Sensor checks:
Tests.
Not Failed Failed All All 1. Check diode D4D for failure.

Test drive driver board for a Replace failed Checks Checks 2. Check diode D5D for failure.
failure. OK not OK 3. Check T1D, T2D for failure.
components.
Not Failed Recalibrate Replace Replace 4. Check drive driver board for failure.
Failed
Replace failed current limit and the logics.
current 5. Check for continuity from emitter bus bar of
Replace components. regen to sensor. power transistors (wire #37) to logics P2-6.
logics. Recalibrate specifications.*
6. Check drive motor for shorts, shorts to frame, and
current limit
opens.
and regen to
specifications.*

68
 SENB8604-02

PROBLEM 11
FOR TRUCKS EQUIPPED WITH REGEN. FOR TRUCKS WITHOUT REGEN, SEE PROBLEM 11A.
Display = “15” and (!) action light flashing: no lift truck operation: line contactor closes and opens.

POSSIBLE CAUSES
Logics not programmed correctly: open circuit on sensing wire between logics pin P2-11 and regen diode D6D (wire #97):
regen contact failure: diode D6D failure.
Burned contact at A2, contact drops out and picks up after regen closes and arcs.
Low battery “ON” without regen.

CHECKS
Verify Option #30 is set correctly.

Correct Not Correct

Verify Option #21 is set correctly. Set Correctly.

Correct Not Correct

Check regen contactor for normal operation or welded tips. Set correctly.

Not Failed Failed

Check regen diode D6D for shorted
condition. Replace
regen contactor.

Not Shorted Shorted Display = Display

Replace logics. Replace “15” Normal
regen diode D6D. Replace logics. Return truck to
operation.

Field Notes
Other Checks:
1. Check ohms of Regen direction and line contactors (should be 35 to 40 ohm).
2. Check for any wear on direction contactors on armature guide plate. (Replace if wear is found).
3. Check for correct position of wires 68 and 92, they could be reversed.
4. Check for the correct position of wires 101 and 102.
5. Check cable connection at motor S1, S2, A1 and A2.
6. Replace current sensor, if all other tests are OK.

69
SENB8604-02

PROBLEM 11A
FOR TRUCKS EQUIPPED WITH REGEN. FOR TRUCKS WITHOUT REGEN, SEE PROBLEM 11.
Display = “15” and (!) action light flashing: no lift truck operation: line contactor closes and opens.and closes.

POSSIBLE CAUSES
Logics not programmed correctly: P2-11 (wire #97) open or shorted: logics failure.

CHECKS
Battery Voltage
Verify C set correctly.

Correct Not Correct

Verify Option #21 is set correctly. Set Correctly.

Correct Not Correct

Check continuity and connections on wire #97 between P2-11 and positive heat sink. Set correctly.

Continuity No Continuity
Replace logics. Repair open wiring.

Field Failure Notes:

1. Slow regen contactor operation incorrect ohm coil.
2. Wire 97 stacked incorrectly in between bus bars.

70
 SENB8604-02

PROBLEM 12
Display = “16”: (!) action light flashing: no lift truck operation: line contactor closes and opens.

POSSIBLE CAUSES
Logics not programmed correctly: open circuit on sensing wire between logics pin P2-11 and regen diode D6D (wire #97):
regen contactor failure: diode D6D failure.

CHECKS
Verify Option #30 is set correctly.

Correct Not Correct

Verify Option #21 is set correctly. Set Correctly.

Display = “16” Display Normal

Check continuity and connections on wire #97 between P2-11 and diode D6D Return truck to operation.
anode. Replace wire if no continuity. Repair loose connection if found.

Not Failed Failed

Check regen diode D6D for Using Problem 49 as a guide,
shorted condition. troubleshoot the regen contactor.
Repair as needed.

Not Shorted Shorted

Replace logics. Replace
regen diode D6D.

Field Notes
Other Checks:
1. Check ohms of Regen direction and line contactors (should be 35 to 40 ohm).
2. Check for any wear on direction contactors on armature guide plate. (Replace if wear is found).
3. Check for correct position of wires 68 and 92, they could be reversed.
4. Check for the correct position of wires 101 and 102.
5. Check cable connection at motor S1, S2, A1 and A2.
6. Replace current sensor, if all other tests are OK.

71
SENB8604-02

PROBLEM 13
Display = “18”: (!) action light flashing: no lift truck operation: line contactor opens and closes.

POSSIBLE CAUSES
Open wire #96: shorted diode D371: Open T371 transistor: short in drive motor: logics defect.

CHECKS
Remove logics connector P2. Inspect P2-2 and P2-1 for corrosion, foreign material, poor crimp or loose contact with logics pin.
Also check the following for continuity:
Wire #92 from P12-7 to P32-1 to P2-2.
Wire #96 from P12-9 to P2-1.
Wire #1 from P12-10 to negative HS.
Wire #34 from P12-3 to positive HS.
Wire #68 from P12-4 to P32-6.

Wires OK Wires Defective

Check resistance of the drive motor shunt field at wires #68 and #92 at connector P32-1 and P32-6. Repair or replace defect.
Measure the diameter of the drive motor, then see the table “Drive and Pump Motor Shunt Field
Resistances” in the Specifications section for the correct resistance.
See the topic Driver Board Tests, Shunt Field Tests.

Tests OK Low Resistance

Disconnect P32. Check for short from drive SE to A1, A2, S1, S2, and motor. Replace drive motor.

OK Short
Check drive driver board Repair motor.
(drive shunt field components only.)

Not Failed Failed

Replace logics. Replace
drive driver board.

72
 SENB8604-02

PROBLEM 14
Display = “19”: (!) action light flashing: no lift truck operation: line contactor opens and closes.

POSSIBLE CAUSES
Logics not programmed correctly: open drive shunt field fuse: poor wire connections: open drive shunt field: shorted T371 transistor: logics defect.

CHECKS
Disconnect the following wires. Visually inspect them for burnt or discolored terminals, loose connections, smashed or compressed
connectors, corrosion or foreign material. Also check the following:
Wire #92 from P12-7 to P32-1 to P2-2.
Wire #96 from P12-9 to P2-1.
Wire #1 from P12-10 to negative HS.
Wire #34 from P12-3 to positive HS.
Wire #68 from P12-4 to P32-6.

Display = “19” Display Normal

Check drive shunt field fuse. Return truck to operation.

Not Failed Failed

Check continuity of wire #34 from positive Replace drive shunt field fuse. Verify drive motor shunt field
heatsink to logics P2-2, wire #92. resistance. Measure the diameter of the drive motor, then see
36/48V =12.35 - 13.65 ohms No the table “Drive and Pump Motor Shunt Field Resistances” in
Continuity the Specifications section for the correct resistance.
72/80V = 11.40 - 38.85 ohms
Display Still “19” Display Normal
Check drive driver board. Repair or
(Shunt field components replace open Check continuity of wire #34 from positive Return truck to
only.) wire or heatsink to logics P2-2, wire #92. operation.
connection.
36/48V =12.35 - 13.65 ohms No
Not Failed Failed
72/80V = 11.40 - 38.85 ohms Continuity
Replace Replace
logics. drive driver Check drive driver board. Repair or
board. (Shunt field components replace open
only.) wire or
connection.
Not Failed Failed
Replace Replace
logics. drive driver
board.

73
SENB8604-02

PROBLEM 15
Display = “20”: (!) action light flashing: no lift truck drive operation.

POSSIBLE CAUSES
Current limit potentiometer P1 out of adjustment. Excessive drive motor current due to severe ramps, abuse, or misapplication.
Drive Pulsing Stall Timer Option set too short for application. 80% Bypass Option ON (Option #15). Current sensor defects: logics defect.

CHECKS
Verify current limit setting.
Do problem #16 procedure.
Increase value of Option #12 (pulse stall timer).
Disable Option #15 if ramp application requires more current than set with P1 current limit potentiometer. (Change setting to “0”).
 SENB8604-02

PROBLEM 16
Display = “21”: (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
Wiring defect: current sensor defect: logics defect.

CHECKS
Disconnect current sensor.
Check continuity from P16-1 to P3-7 (wire #2).
Check continuity from P16-2 to P3-8 (wire #42).
Check continuity from P16-3 to P3-6 (wire #85).

Continuity OK Continuity
Check for short to battery negative (wire #1) in wire #2.
not OK
Check for short to battery negative (wire #1) in wire #85. Repair or
Check for short between wire #42 and wire #85. replace open
wires.
No Shorts Shorts
With current sensor and logics plugged in and truck powered up, measure the voltage between P3-6 Repair
(wire #85) and P3-7 (wire #12). It should measure between 7.15 and 7.5 volts. Shorts.
Voltage OK Voltage Not OK
Plug in known good current sensor. Power up truck. With current sensor and logics plugged in,
power up truck. Measure the voltage
between P3-8 (wire #42) and P3-7 (wire #2).
It should measure between 3.6V and 4.0V.

Truck Powers Up Normally Display = “21” Voltage Voltage Not ON

With known good current sensor Replace logics. OK Plug in known good sensor.
plugged in and logics plugged in, Truck OK, Power up truck.
power up truck. Measure the voltage return to
between P3-6 (wire #85) and P3-7 operation.
(wire #2). It should measure between
7.15 and 7.5 volts.
Voltage OK Voltage Not ON Truck Powers Up Normally Display =
“21”
Truck OK, Replace logics. With known good current sen-
return to sor plugged in and logics Replace
operation. plugged in, power up truck. logics.
Measure the voltage between
P3-6 (wire #85) and P3-7 (wire
#2). It should measure between
7.15 and 7.5 volts.
Voltage OK Voltage
Truck OK, Not ON
return to Replace
operation. logics.
75
SENB8604-02

PROBLEM 17
Display = “24”: (!) action light flashing: no lift truck operation. Line contactor opens and closes.

POSSIBLE CAUSES
Wiring defect: drive driver board defect: logics defect.

CHECKS
Check continuity between P2-5 and R312 (wire #31).
Check continuity between R312 and P12-15 (wire #32).
Check continuity between P12-16 and positive HS (wire #34).

Continuity OK Continuity Not OK

Check wires #31, #32, and #34 for burnt,. crushed, or shorted areas. Repair or replace open
wires.
Wires OK Wires Not Ok
Measure the resistance of R312. It should be: Repair or replace wire(s).
36/48V = 34.2-37.80 ohms
72/80V =71.25-78.75 ohms.

Resistance OK Resistance Not OK

Perform drive driver board tests. Replace
logics.

Test OK Test Not OK

Replace logics. Replace
drive driver
board.

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 SENB8604-02

PROBLEM 18
Display = “25”: (!) action light flashing: no lift truck operation.

POSSIBLE CAUSES
Accelerator control not adjusted or defective: dirt on optical switches: open wiring: logics defect.

CHECKS
Check accelerator control adjustment. See the Systems Operation section of this manual.

Adjustment OK Adjustment Not OK

Disconnect P9 connector. With keyswitch closed, check for battery voltage between P9-A (wire #1) and Adjust control to proper
P9-B (wire #4). (Be sure that the problem is not a defective keyswitch.) specifications.

OK If Low
Check voltage between P9-C and P9-A. Repair open wire between P9-A(wire #1) and
battery negative or P9-B (wire #4) and
15 Volts Not 15 Volts battery positive.
Check continuity Check continuity of wire #8 between logics P1-15
Plug accelerator back of wire #8 and P9-C.
into P-9 connector. between logics
Check voltages at logics P1-15 and P9-C.
P1-15 as follows:
Continuity OK Continuity Not OK
Accelerator Voltage
Pedal Position Check for short to battery nega- Repair or replace
Fully UP 1.2 to tive (wire #1) in wire #8. broken wire.
12.5 volts
No Short Short
Fully depressed 1.6 to
2.0 volts Replace logics. Repair or
replace shorted
Voltage should decrease
wire.
from max to min as pedal is
depressed.

Voltage Voltage OK
readings OK but problem
Replace persists
accelerator Replace
control. logics.

77
SENB8604-02

PROBLEM 19
Display = “26”: (!) action light flashing: no lift truck operation.

POSSIBLE CAUSES
Accelerator control not adjusted or defective: dirt on optical switches: open wiring: logics defect.

CHECKS
Check accelerator control adjustment. See the Systems Operation section of this manual.

Adjustment OK Adjustment Not OK

Disconnect P9 connector. With keyswitch closed, check for battery voltage between P9-A Adjust control to proper
(wire #1) and P9-B (wire #4). (Be sure that the problem is not a defective keyswitch.) specifications.
OK If Low
Check voltage between P9-C and P9-A. Repair open wire between
P9-A(wire #1) and battery
negative or P9-B (wire #4) and
15 Volts Not 15 Volts
battery positive.
Plug accelerator back into Check continuity of wire #8 between
P-9 connector. Check logics P1-15 and P9-C.
voltages at logics P1-15
as follows: Continuity OK Continuity
Accelerator Voltage Not OK
Check for short to
Pedal Position
battery negative Repair or
Fully UP 1.2 to
(wire #1) in wire #8. replace broken
12.5 volts
wire.
Fully depressed 1.6 to
No Short
2.0 volts Short
Repair or
Voltage should decrease Replace replace
from max to min as pedal is logics. shorted
depressed.
wire.
Voltage Voltage OK
readings but problem
Not OK persists
Replace Replace
accelerator logics.
control.

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 SENB8604-02

PROBLEM 20
Display = “29”: (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
Logics not programmed correctly: open circuit/short circuit in wire #115 and #116 connecting speed sensor to logic:
faulty speed sensor: faulty logics.

CHECKS
Measure the resistance of the speed sensor. It should be 2.3kΩ +/- 0.2 kΩ.

Resistance OK Resistance Not OK

Check wires #115 and #116 for opens or shorts between speed sensor Adjust control to proper
connector P52 and logics connector P1. specifications.

Wires OK Wires Not OK

Using the AC Volts setting on the volt-ohmmeter, measure the voltage Replace speed sensor.
between P1-18 and P1-19. This voltage should increase as the wheels turn
faster and decrease as the wheels turn slower.

Voltage OK Voltage Not OK

Replace accelerator control. Replace speed sensor.

Field Notes
Other Checks:
1. If Code 29, 15 and/or 16 are found together in history, then check regen and line contactors.
2. Check ohms of Regen direction and line contactors (should be 35 to 40 ohm).
3. Check for any wear on direction contactors on armature guide plate. (Replace if wear is found).
4. Check for correct position of wires 68 and 92, they could be reversed.
5. Check for the correct position of wires 101 and 102.
6. Check cable connection at motor S1, S2, A1 and A2.
7. Current sensor can check good and still code 29.
8. Replace current sensor, if all other tests are OK. Current sensor can still check good and still code 29.
9. Loose connection on directional contactors.

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SENB8604-02

PROBLEM 21
Display = “30”: (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
Shorted T1P or T2P: open wiring: failed pump driver board: failed logics: open circuit in pump motor PA1,
PS2 cables: welded pump contactor tips.

CHECKS
Disconnect the battery: check pump motor contactor for welded or shorted tips. Check contactor for free tip movement.

Tips Not Shorted Tips Shorted

Connect battery: close the seat key switches. Repair or replace
contact. Check
Line contactor closes then opens. Pump Line contactor closes then opens. Pump BDI adjustment.
motor does not turn. Display = “30”. motor turns a small amount. Display = “30”.
Disconnect battery: remove logics cover: check Check T1P, T2P for a short circuit.
continuity or wire #45 at emitter connector of
T2P to logics P2-10. No Shorts Shorts

No Continuity Continuity Test pump driver board. Replace failed

components.*
Replace logics. Check continuity from PA1 to
PS2 at panel.
Test Test
Continuity No OK Failed
Replace Continuity
logics. Replace logics. Replace pump
Check motor driver board.
and cables
and repair.

*NOTICE: Damage to the control panel could result.

To prevent further damage, before T1P, T2P, or the
drive driver board are replaced, complete the follow-
ing checks:
1. Check diode D4D for a failure.
2. Check diode D5D for a failure.
3. Check T1P, T2P for a failure.
4. Check pump driver board for a failure.
5. Check head capacitors for a failure.
6. Check for continuity from T2P emitter
(wire #45) to logics P2-10.

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PROBLEM 22
Display = “31”: (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
Faulty wire connections: D4P or T1P and T2P failed: failed pump driver board failed logics.

CHECKS
Disconnect the following wires. Visually inspect them for burnt or discolored terminals, loose connections, smashed or
compressed connectors, corrosion or foreign material. Also check:
Wire #45 from emitter of transistor T1P and T2P to P4-7 and P2-10.
Wire #34 from pump driver board to positive heatsink.
Wire #1 from pump driver board to negative heatsink.
Wire #229 from pump shunt (+) to P2-18.
Wire #29 from pump shunt (-) to P2-19.
Repair any defects then reconnect the wires.

Display = “31” Display Normal

Check diode D4P for a failure. Return truck to operation.

Not Failed Failed

Check transistors T1P, T2P for a failure. Replace failed diode*.

Not Failed Failed

Check pump driver board. Replace
transistor.*

Not Failed Failed

Replace logics. Replace
pump driver board.

*NOTICE: Damage to the control panel could result. To prevent further damage, before T1P, T2P, or the drive
driver board are replaced, complete the following checks:
1. Check diode D4P for a failure.
2. Check head capacitors for a failure.
3. Check T1P, T2P for a failure.
4. Check pump driver board for a failure.
5. Check for continuity from emitter bus bar of power transistors (wire #45) to logics P2-10.

81
SENB8604-02

PROBLEM 23
Display = “32”: (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
Faulty wire connections: D4P or T1P and T2P failed: failed pump driver board failed logics.

CHECKS
Disconnect the following wires. Visually inspect them for burnt or discolored terminals, loose connections, smashed or
compressed connectors, corrosion or foreign material. Also check:
Wire #45 from emitter of transistor T1P and T2P to P4-7 and P2-10.
Wire #34 from pump driver board to positive heatsink.
Wire #1 from pump driver board to negative heatsink.
Wire #119 from pump shunt (+) to P2-18.
Wire #29 from pump shunt (-) to P2-19.
Repair any defects then reconnect the wires.

Display = “32” Display Normal

Check diode D4P for a failure. Return truck to operation.

Not Failed Failed

Check transistors T1P, T2P for a failure. Replace failed diode.*

Not Failed Failed

Check pump driver board. Replace
transistor.*

Not Failed Failed

Replace logics. Replace
pump driver board.

*NOTICE: Damage to the control panel could result. To prevent further damage, before T1P, T2P, or the drive
driver board are replaced, complete the following checks:
1. Check diode D4P for a failure.
2. Check head capacitors for a failure.
3. Check T1P, T2P for a failure.
4. Check pump driver board for a failure.
5. Check for continuity from emitter bus bar of power transistors (wire #45) to logics P2-10.

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PROBLEM 24
Display = “33”: (!) action light flashing: no lift truck operation: line contactor closes and opens.

POSSIBLE CAUSES
Failure in pump circuit.

CHECKS
See problems 22 and 23, Display = “31” and “32”. Do both procedures.

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SENB8604-02

PROBLEM 25
Display = “38”: (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
Open wire #72: shorted diode D351: open transistor T351: shorted shunt field: failed logics.

CHECKS
Remove logics connector P2. Inspect P2-4 and P2-3 for corrosion, foreign material, poor crimp or loose contacts with logics pin.
Also check the following:
Wire #72 from P12-8 to P2-3.
Wire #71 from P12-6 to P32-2 to P2-4.
Wire #1 from P12-10 to positive HS.
Wire #69 from P12-2 to P32-5.

Wires OK Not OK
Check resistance of pump motor shunt field at wires #69 and #71. Measure the diameter of the pump Repair or replace defect.
motor, then see the table “Drive and Pump Motor Shunt Field Resistances” in the Specifications section
of this manual for the correct resistances.

Resistance OK Low Resistance

Check pump driver board. (Shunt field components only.) Repair or replace
pump motor.

Not Failed Failed

Replace logics. Replace
pump driver board.

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PROBLEM 26
Display = “39”: (!) action light flashing: no lift truck operation.

POSSIBLE CAUSES
Open shunt field fuse: poor wire connections: open shunt field: shorted transistor T351: failed logics.

CHECKS
Disconnect the following wires. Visually inspect them for burnt or discolored terminals, loose connections, smashed or compressed
connectors, corrosion or foreign material.
Wire #72 from P12-8 to P2-3.
Wire #71 from P12-6 to P32-2 to P2-4.
Wire #1 from P12-10 to negative HS.
Wire #34 from P12-1 to positive HS.
Wire #69 from P12-2 to P32-5.
Repair any defects, then reconnect the wires.

Display = “39” Display Normal

Check drive shunt field fuse. Return truck to operation.

Not Failed Failed

Check continuity of wire #34 from positive Replace shunt field fuse. Verify pump shunt field resistance.
heatsink to logics P2-4, (wire #71). Measure the diameter of the pump motor, then see the table
“Drive and Pump Motor Shunt Field Resistances” in the
7 to 10 ohms No Specifications section for the correct resistance.
Continuity
Check pump driver board Display Still “39” Display Normal
(shunt field Repair or
components only.) replace open Check continuity of wire #34 from positive Return truck to
wire or heatsink to logics P2-4, (wire #71). operation.
connection.
7 to 10 ohms No
Not Failed Failed
Continuity
Replace Replace Check pump driver board
logics. pump driver (shunt field Repair or
board. components only.) replace open
wire or
connection.
Not Failed Failed
Replace Replace
logics. pump driver
board.

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SENB8604-02

PROBLEM 27
Display = “40”: (!) action light flashing: no lift truck operation. Line contactor closes then opens.

POSSIBLE CAUSES
Excessive pump current: pump shunt defect: wiring defect: pump/pump motor defect: failed logics.

CHECKS
Check continuity between P2-18 and pump shunt. (Wire #119, side closest to negative heatsink.)
Check continuity between P2-19 and pump shunt. (Wire #29, side attached to standoff.)

Continuity OK Continuity Not OK

Check wire #29 for burnt, smashed, cut or shorted areas. Repair or replace open
wires.
Wires OK Wires Not OK
Check pump shunt connections to make sure they are tight and there is Repair or replace
no corrosion between the terminals for wire #29 or #119 and the shunt. defective wires.

Tight Not Tight

Attach clamp-on ammeter to PS2 cable. Power up truck and Tighten
check current. In steer idle, current should be less than 50A. bolts.
Current OK Current High
Replace logics. Correct pump/motor pump problem. Pump
could be binding. Cables running to pump
motor could be connected incorrectly.
Pump motor could be defective.

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 SENB8604-02

PROBLEM 28
Display = “41”: (!) action light flashing: no lift truck operation. Line contactor closes then opens.

POSSIBLE CAUSES
Pump shunt defect: wiring defect: pump/pump motor defect: failed logics.

CHECKS
Check continuity between P2-18 and pump shunt. (Wire #119, side closest to negative heatsink.)
Check continuity between P2-19 and pump shunt. (Wire #29, side attached to standoff.)
Wire #119 and #29 are reversed. (Wire #29 is on heat sink.)

Continuity OK Continuity Not OK

Check wires #29 and #119 for burnt, smashed, cut or shorted areas. Repair or replace
open wires.
Wires OK Wires Not OK
Check pump shunt connections to make sure they are tight and there is no Repair or replace
corrosion between the terminals for wire #29 or #119 and the shunt. defective wires.
Scrape coating off board if needed. Do NOT disconnect from logics.

87
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PROBLEM 29
Display = “44”: (!) action light flashing: no lift truck operation. Line contactor closes then opens.

POSSIBLE CAUSES
Wiring defect: pump driver board defect: failed logics.

CHECKS
Check continuity between P2-7 and P4-1 (wire #79).
Check continuity between P2-8 and P4-2 (wire #117).
Check continuity between P2-9 and P4-4 (wire #118).
Check continuity between P4-5 and Positive HS (wire #34).

Continuity OK Continuity Not OK

Check wires #79, #117, #118, and #34 for burnt, smashed, cut or shorted areas. Repair or replace
open wires.
Wires OK Wires Not OK
Perform pump driver board tests. See the topic, “Pump Driver Board Tests” Repair or replace
in this section of the manual. defective wires.

Pump Driver Board OK Pump Driver Board Not OK

Replace logics. Replace
pump driver board.

* Typical Amps at steer idle 15 - 50 and 250 at steer lock.

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 SENB8604-02

PROBLEM 30
Display = “50”: (!) action light flashing: no lift truck operation. Line contactor closes then opens.

POSSIBLE CAUSES
Bypass contactor tips and pump contactor shorted. Shorted T1D, T2D, T1P, T2P, and T3D: poor connection at logics connector:
defective drive and/or pump driver boards.

CHECKS
See problems 9 and 21, Display = “10” and Display = “30”. Perform both procedures.

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SENB8604-02

PROBLEM 31
Display = “51”: (!) action light flashing: no lift truck operation. Line contactor closes then opens.

POSSIBLE CAUSES
Blown line fuse: failed logics: faulty wiring.

CHECKS
See problems 10, 22, and 23 (Display = “11”, Display = “31”, Display = “32”, and Display = “33”). Perform all four procedures.

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 SENB8604-02

PROBLEM 32
Display = “60”: (!) action light flashing: no lift truck operation. Line contactor closes then opens.

POSSIBLE CAUSES
Serial communications fault between display and logics.

CHECKS
Check the following wires for continuity. Also visually inspect their connections for burnt or discolored terminals, loose connections,
smashed or compressed connectors, corrosion or foreign materials.
P3-4 to P6-4 (wire #12).
P3-5 to P6-3 (wire #16).
P6-2 to key switch (wire #4).
P6-1 to battery negative (wire #1).
P3-18 to key switch (wire #4).
P3-20, P3-21, P1-21 to battery negative (wire #1).

Checks OK Checks Not OK

Check for short to battery negative (wire #1) in the following wires: Repair or replace
Wire #12. open wires.
Wire #16.
Wire #4.

Checks OK Checks Not OK

Connect a spare display unit to harness plug P6 and turn the key switch on. Fix shorts.

Spare Display Functions Properly Display = “60”

Replace display. Replace logics.

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SENB8604-02

PROBLEM 33
Display = “61”: (!) action light flashing: no lift truck operation. Line contactor closes then opens.

POSSIBLE CAUSES
Internal EEPROM memory error in microprocessor or logics.

CHECKS
Replace logics.

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 SENB8604-02

PROBLEM 34
Display = “65”: (!) action light flashing: no lift truck operation. Line contactor never closes.

POSSIBLE CAUSES
Truck size not initialized.

CHECKS
Enter setup mode and access Option #30, Truck Size and Type (see the topic “Setup Options” in the Systems Operation section
of this manual).
Set the value of the option according to the size of your cushion truck.
All service replacement logics boards are shipped with Option #30 set to “0.00”. You must always enter setup mode and set the
value according to the size of your cushion truck.
Remember, Option #30 will not be programmed to new values until the DRS switch is moved to the RUN position while in the
SETUP mode. This will cause the “triple bar” display to show up, indicating successful programming of the new truck size and type.
Exit Setup mode and power up the truck in Run mode.
If the display still reads “65”, replace logics.

93
SENB8604-02

PROBLEM 35
Display = “66”: (!) action light flashing: no lift truck operation.

POSSIBLE CAUSES
Internal microprocessor “Watchdog” timer failure.

CHECKS
Replace logics.

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 SENB8604-02

PROBLEM 36
Display = “68” or “69”: (!) action light flashing: no lift truck operation. Line contactor closes and opens.

POSSIBLE CAUSES
68: Battery volts too low for chosen jumper.
69: Battery volts too high for chosen jumper.
Short between connector P5-16 and P6-1

CHECKS
Check the following wires for continuity. Also visually inspect their connections for burnt or discolored terminals, loose connections,
smashed or compressed connectors, corrosion or foreign materials.
P3-4 to P6-4 (wire #12)
P3-5 to P6-3 (wire #16)
P6-2 to key switch (wire #4)
P6-1 to battery negative (wire #1)
P3-18 to key switch (wire #4)
P3-20, P3-21, P1-21 to battery negative (wire #1).

Checks OK Checks Not OK

Check for short to battery negative (wire #1) in the following wires: Repair or replace
Wire #12. open wires.
Wire #16.
Wire #4.

Checks OK Checks Not OK

Connect a spare display unit to harness plug P6 and turn the key switch on. Fix shorts.

Spare Display Functions Properly Display = “60”

Replace display. Replace logics.

Field Notes
Also Check:
1. Open line Contactor Coil.

95
SENB8604-02

PROBLEM 37
Seat switch or circuit defect.

POSSIBLE CAUSES
Seat switch defect: wiring to seat defect: logics defect.

CHECKS
Measure the voltage at logics P1-13 (wire #7, silver area) with weight on and off seat. Scrape coating off card pins if needed.
Voltage measured should be:
High with weight off the seat.
Low with weight on the seat.

Voltage OK Voltage Not OK

Disconnect seat switch and check the continuity with weight on and off the seat. Resistance should be: Verify problem still exists.
If it does, replace logics.
Less than 50 ohms with weight on the seat.
OL (infinite) with weight off the seat.

OK Not OK
Check continuity from P1-13 to seat switch (wire #7). Replace
Check continuity from seat switch to battery negative (wire #1). seat switch.
OK Not OK
Check for short to battery negative Correct any open wires.
(wire #1) in wire #7. Correct short.

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 SENB8604-02

PROBLEM 38
Direction switch circuit defect.

POSSIBLE CAUSES
Direction switch defect: wiring to direction seat defect: logics defect.

CHECKS
Measure the voltage on logic card (silver area) at P1-10 (wire #14) and P1-9 (wire #15.) Scrape coating off pins if needed.
Use the following chart to determine proper voltages.

Logics Pin FWD REV Neutral

P1-10 Low High High
P1-9 High Low High

Voltage Not OK Voltage OK

Disconnect direction switch and check switch for proper continuity. Verify problem still exists.
If it does, replace logics.

Lever Position FWD (wire #14) REV (wire #15)

to BAT (wire#1) to BAT (wire #1)
FWD <50 ohms OL (infinite)
Neutral OL (infinite) OL (infinite)
REV OL (infinite) <50 ohms

Check OK Check Not OK

Check continuity from logics P1-10 (wire #14) and P1-9 (wire #15) Replace
to direction switch. seat switch.

OK Not OK
Check for short to battery negative (wire #1) Correct any open wires.
in wire #14 or #15. Correct short.

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SENB8604-02

PROBLEM 39
Foot-operated direction switch circuit defect.

POSSIBLE CAUSES
Direction switch defect: wiring to direction seat defect: service brake interrupt switch defect: logics defect.

CHECKS
Measure the voltage on logic card (silver area) at P1-10 (Wire #14) and P1-9 (wire #15). Scrape coating off card pins if needed. Use
the following chart to determine proper voltages.

Logics Pin FWD REV Neutral

P1-10 Low High High
P1-9 High Low High

Voltage Not OK Voltage OK

Disconnect direction switch and check switch for proper continuity. Verify problem still exists.
If it does, replace logics.

Lever Position FWD (wire #14) REV (wire #15)

to BAT (wire#1) to BAT (wire #1)
FWD <50 ohms OL (infinite)
Neutral OL (infinite) OL (infinite)
REV OL (infinite) <50 ohms

Check OK Check Not OK

Check continuity from P1-10 to P61-2 (wire #14). Replace
Check continuity from P1-9 to P61-3 (wire #15). direction switch.
Check continuity from P61-1 to battery negative (wire #1).

OK Not OK
Check for short to battery negative (wire #1) Correct any open wires.
in wire #14 or #15. Correct short.

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 SENB8604-02

PROBLEM 40
Park brake switch circuit defect.

POSSIBLE CAUSES
Park brake switch defect: wiring defect: logics defect.

CHECKS
Check park brake switch adjustment to make sure park brake switch is activated by park brake lever.

Adjustment OK Adjustment Not OK

Measure the voltage at logics P1-11 (wire #91) with park brake applied and released. Adjust lever to make
Scrape coating off pin card if needed. Voltage should be: proper engagement
with switch.
High—Brake applied.
Low—Park brake released.
Voltage Not OK Voltage OK
Disconnect park brake switch and check continuity with park brake Verify problem still exists.
applied and released. If it does, replace logics.
Resistance should be:
<50 ohms with park brake applied.
OL (infinite) with park brake released.
OK Not OK
Check for continuity from park brake switch to P1-11 Replace
(wire #91). park brake
Check for continuity from park brake switch to battery switch.
negative (wire #1).

Checks OK Checks Not OK

Check for short to battery negative Correct open wire.
(wire #1) in wire #91. Repair short.

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PROBLEM 41
Service brake switch circuit defect.

POSSIBLE CAUSES
Service brake switch defect: wiring defect: logics defect.

CHECKS
Check service brake switch adjustment to make sure service brake switch is activated by service brake lever.

Adjustment OK Adjustment Not OK

Measure the voltage at logics P1-12 (wire #113) with service brake applied and released. Adjust pedal to make
Scrape coating off card pins if needed. Voltage should be: proper engagement
with switch.
High—Service brake applied.
Low—Service brake released.
Voltage Not OK Voltage OK
Disconnect service brake switch and check continuity with service brake Verify problem still exists.
applied and released. If it does, replace logics.
Resistance should be:
<50 ohms—Service brake applied.
OL (infinite)—Service brake released.
OK Not OK
Check for continuity from service brake switch to P40-C to Replace
P1-12 (wire #113). service
brake
Check for continuity from service brake switch P40-A to switch.
battery negative (wire #1).

Checks OK Checks Not OK

Check for short to battery negative Correct open wire.
(wire #1) in wire #113. Repair short.

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PROBLEM 42
Accelerator switch circuit defect.

POSSIBLE CAUSES
Accelerator control not adjusted or defective: dirt on optical switches: open wiring: logics defect.

CHECKS
Check accelerator control adjustment. See the Systems Operation section of this manual.

Adjustment OK Adjustment Not OK

Disconnect P9 connector. With keyswitch closed, check for battery voltage between P9-A (wire #1) Adjust control to the
and P9-B (wire #4). (Be sure that the problem is not a defective keyswitch.) proper specifications.

OK If Low
Check voltage between P9-C and P9-A. Repair open
wire between
P9-A (wire #1)
and battery
15 Volts Not 15 Volts negative or P9-
B (wire #4) and
Plug accelerator back into P9 connector. Check continuity of wire #8 between battery
Check voltages at logics P1-15 as follows: logics P1-15 and P9-C. positive.

Accelerator Control Pedal Voltage

Continuity OK Continuity
Position
Not OK
Check for short to battery
Fully UP 12 to 12.5 volts Repair or
negative (wire #1 in wire #8).
Fully depressed 1.6 to 2.0 volts replace
broken
Voltage should decrease from max to min wire.
as pedal is depressed.
No Short Short
Voltage Readings Voltage Ok But Replace Repair or
Not Ok Problem Persists logics. replace
Replace Replace logics. shorted
accelerator control. wire.

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SENB8604-02

PROBLEM 43
Battery Discharge Indicator (BDI) display shows no bars. Drive may be slow: power steering is normal.
No hydraulics (lift or tilt). BDI circuit defect.

POSSIBLE CAUSES
Option #16 (BDI Reset value) set too high: battery discharged or defective: logics defect:
J1, J2, J3, or J4 jumper missing or in wrong position: BDI needs adjustment.

CHECKS
Verify that the value of Setup Option #16 is as expected. Typical value is 6.

Value OK Value Set Too High

Connect battery, turn on key switch, close seat switch, and measure voltage from line contactor to Reset Value.
negative heatsink. Voltage readings should be:
36V Battery—greater than 34.8V
48V Battery— greater than 46.4V
72V Battery—greater than 69.6V
80V Battery—greater than 77.3V

Voltage OK Voltage Low

Make sure jumper connector in the logics is in the correct position for the Verify problem still exists.
battery used. (J1=36V, J2=48V, J3=72V, J4=80V). If it does, replace logics.

Jumper Position Correct Not Correct

With key on, seat switch and line contact closed, Move
measure voltage at logics P3-18. jumper to
correct
Battery Voltage Less than Battery position and
Voltage recycle key
Adjust BDI to specifications. The switch.
key must be turned off between Repair shorted wire or
each adjustment of P5*. If BDI will high resistance
not adjust, replace logics. connection causing the
improper voltage.

*NOTE: Display will show no bars until BDI is adjusted far enough to change the display to a six-bar reading.

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PROBLEM 44
Lift switch 1 and 2 circuit defects.

POSSIBLE CAUSES
Lift switch 1 and 2 not adjusted properly or defective: wiring defect: logics defect.

CHECKS
Check mechanical linkage for proper operation. Switch 1 should “click” in before switch 2.

Linkage OK Linkage Not OK

Measure the voltage on logics card (silver area) at P1-1 and P1-2. Scrape coating off card pins if Adjust linkage.
needed. Use the following chart to determine proper voltages:

Logics Pin Lift Lever Fully Lift Lever Fully Lift Lever 1/2 Lift Lever
FWD BACK BACK NEUTRAL
P1-1 High Low Low High
P1-2 High Low High High

Voltage NOT OK Voltages OK

Disconnect switches and check continuity with lever in neutral position Verify problem still
and pulled fully back. Resistance for these switches should be: exists. If it does,
replace logics.
Neutral—OL (infinite)
Fully Back—<50 ohms.
CHECK OK NOT OK
Check continuity between P13-5 to P1-1 (wire #13). Replace
defective
Check continuity between P13-6 to P1-2 (wire #81). switches.
Check continuity between P13-1 to battery negative
(wire #1).
Checks OK Checks
Check for short to battery negative Not OK
(wire #1) in wire #13. Repair or
Check for short to battery negative replace open
(wire #1) in wire #81. wire.

Repair shorts.

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PROBLEM 45
Tilt switch circuit defects.

POSSIBLE CAUSES
Tilt switch not adjusted properly or defective: wiring defect: logics defect.

CHECKS
Check mechanical linkage for proper operation. Switch should “click” when depressed.

Linkage OK Linkage Not OK

Measure the voltage on logics card (silver area) at P1-13. Scrape coating off card pins if needed. Adjust linkage.
Use the following chart to determine proper voltages:

Logics Pin Lift Lever Fully Lift Lever Fully Lift Lever
FWD BACK NEUTRAL
P1-3 Low Low High

Voltage NOT OK Voltages OK

Disconnect switches and check continuity with lever fully forward, in neutral Verify problem
position and pulled fully back. Resistance for these switches should be: still exists.
If it does,
Fully FWD—<50 ohms
replace logics.
Neutral—OL (infinite)
Fully Back—<50 ohms.

CHECK OK NOT OK
Check continuity between P13-2 to P1-3 (wire #89). Replace
Check continuity between P13-2 to battery negative (wire #1). defective
switches.

Checks OK Checks
Check for short to battery negative Not OK
(wire #1) in wire #89.
Repair or
Repair shorts. replace open
wire.

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PROBLEM 46
Aux 1 switch circuit defect.

POSSIBLE CAUSES
Aux 1 switch not properly adjusted or defective: wiring defect: logics defect.

CHECKS
Check mechanical linkage for proper operation. Switch should “click” when depressed.

Linkage OK Linkage Not OK

Measure the voltage on logics card (silver area) at P1-4. Scrape coating off card pins if needed. Adjust linkage.
Use the following chart to determine proper voltages:

Logics Pin Aux 1 Fully Aux 1 Lever Aux 1 Lever

FWD Fully BACK NEUTRAL
P1-4 Low Low High

Voltage NOT OK Voltages OK

Disconnect switches and check continuity with lever fully forward, in neutral Verify problem still
position and pulled fully back. Resistance should be: exists. If it does,
replace logics.
Fully FWD—<50 ohms
Neutral—OL (infinite)
Fully Back—<50 ohms.

CHECK OK NOT OK
Check continuity between P13-3 to P1-4 (wire #88). Replace
Check continuity between P13-3 to battery negative (wire #1). defective
switches.

Checks OK Checks
Check for short to battery negative Not OK
(wire #1) in wire #88. Repair or
Repair shorts. replace open
wire.

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PROBLEM 47
Aux 2 switch circuit defect.

POSSIBLE CAUSES
Aux 2 switch not properly adjusted or defective: wiring defect: logics defect.

CHECKS
Check mechanical linkage for proper operation. Switch should “click” when depressed.

Adjustment OK Adjustment Not OK

Measure the voltage on logics card (silver area) at P1-5. Scrape coating off card pins if needed. Adjust lever to make
Use the following chart to determine proper voltages: proper engagement
with switch.
Logics Pin Aux 2 Fully Aux 2 Lever Aux 2 Lever
FWD Fully BACK NEUTRAL
P1-5 Low Low High

Voltage NOT OK Voltages OK

Disconnect switches and check continuity with lever fully forward, in neutral Verify problem still
position and pulled fully back. Resistance should be: exists. If it does,
replace logics.
Fully FWD—<50 ohms
Neutral—OL (infinite)
Fully Back—<50 ohms.

CHECK OK NOT OK
Check continuity between P13-4 to P1-5 (wire #87). Replace
Check continuity between P13-4 to battery negative (wire #1). park brake
switch.

Checks OK Checks
Check for short to battery negative Not OK
(wire #1) in wire #87. Repair or
Repair short. replace open
wire.

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PROBLEM 48
Hydraulic speed check. (Hydraulic Speed less than desired.)

POSSIBLE CAUSES
Speed options set to incorrect value for Lift, Tilt, or Aux in programmable Setup Options.

CHECKS
Enter Setup Mode and access Option #2 (First Group) Lift 1 Speed.
(See the topic “Setup Options” in the Systems Operation section of this manual).
Set the option to the correct value.
Exit Setup Mode and power up the truck in RUN mode. Check lift speed. Repeat procedure if lift speed still needs adjustment.
Remember, Option #2 will not be programmed to new values until the DRS switch is moved to the RUN position while in SETUP
mode. This will cause the “Triple Bar” display to show up, indicating successful programming of the new truck size and type.
Repeat the procedure if necessary for other hydraulic functions:
Option 3 – Lift 2
Option 4 – Tilt Speed
Option 5 – Aux 1 Speed
Option 6 – Aux 2 Speed.

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PROBLEM 49
Incorrect contactor operation.

POSSIBLE CAUSES
Wiring defect: contactor defect: logics defect.

CHECKS
During the self-diagnostic test, which of the following occurs?

Contactor does not pull in or does not remain pulled in. Contactor remains
Disconnect the battery. Check for free mechanical movement of contactor bridge (tips). in whenever the key
switch is closed
Movement OK Movement Not Free through all tests.
Remove logics cover. Disconnect P3. Check continuity from P3-16 Repair or replace See OTHER PROBLEMS
(wire #38) to coil X terminal of the contactor with correct operation. contactor. list, “Any contactor closes
when key switch is
Continuity No closed.”

Measure continuity from the appropriate P3 socket to the Continuity

coil terminal Y of the contactor that has incorrect operation.
Determine the P3 socket with respect to the contactor that Replace
has incorrect operation as follows: display unit.
Line . . . . . . . . . . . . . . .P3-9, wire #26
Pump Bypass . . . . . . .P3-10, wire #30
Drive Bypass . . . . . . . .P3-11, wire #35
Reverse Direction . . . .P3-13, wire #19
Forward Direction . . . .P3-12, wire #20
Regen . . . . . . . . . . . . .P3-14, wire #75.
Continuity No Continuity
Perform contactor tests. Repair or
(Coil Resistance, Coil Suppression, Coil Pulsing). replace wire.

Tests OK Tests Not OK

Connect P3 and run Repair or
“Self” diagnostics again. replace
If contactor does not close, contactor.
replace logics.

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 SENB8604-02

PROBLEM 50
Any contactor closes when key switch is closed.

POSSIBLE CAUSES
Wiring defects: failed logics.

CHECKS
Connect the battery. Does the line contactor close when the key switch is closed?

Yes No
Check stored fault codes. Verify E1 is present.

No Yes
See the SELF DIAGNOSTICS Which contactor closed? Disconnect the battery.
PROBLEMS list; “Seat Switch Remove logics cover and disconnect logics P3 connector.
circuit defect.” Check for a short circuit from control panel battery negative
(negative heat sink) to P3 harness connector socket.
Determine the P3 socket with respect to the contactor that
closed as follows:
Line . . . . . . . . . . . . . . .P3-9
Pump Bypass . . . . . . .P3-10
Drive Bypass . . . . . . . .P3-11
Reverse Direction . . . .P3-13
Forward Direction . . . .P3-12
Regen . . . . . . . . . . . . .P3-14.

Continuity No Continuity
Repair or replace shorted wire. Replace logics.

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PROBLEM 51
Drive motor does not operate or operates with low power or is erratic. Pump and power steering systems operation normal.

POSSIBLE CAUSES
Accelerator control defective: drive driver board defective: current limit set too low: wiring defect: failed logics.

CHECKS
Perform self-diagnostics.

Passed Failed
Turn current limit potentiometer P1 clockwise and check operation. See respective PROBLEM
for defective circuit.
Wheels Don’t Spin Wheels Spin
Check R312 for correct resistance. Adjust current
limit to
36/48V = 34.20 - 37.80 ohms
specification.
72/80V = 71.25 - 78.75 ohms
In Specification Not in
Check wires #31 and #32 for a good connection on Specification
R312. Check wires #36 to base of transistors T1D and
T2D. Check continuity of wire #37 from emitter T2D to Replace resistor
logics P2-6. R312.

All OK Defective
Check diodes D5D and D4D for shorts Repair or
or open circuits. replace.

Diodes OK Defective
Check drive motor for Replace
open circuit. Check cur- defective
rent shunt and wiring for diode.
continuity. Check drive
driver board for defects.
Checks OK Defective
Replace logics. Replace
drive driver
board.

*NOTE: Reset current limit to specifications after repairs are complete.

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PROBLEM 52
Poor acceleration: loss of power on ramps.

POSSIBLE CAUSES
Current limit out of adjustment: cables or connections to motor defective: T1D and T2D degenerative or defective:
motor defective: failed logics.

CHECKS
Verify the value of Setup Option #8 (Variable Acceleration) is set high enough.

Value OK Value Too

Verify value of Setup Option #15 (80% Bypass). Low
Reset to
Value = 1 (ON) Value = 0 (OFF) higher value.
Reset to 0 (off). By setting this option to 0, you are removing a feature Make sure the truck passes all
that helps protect the drive motor from abuse. This may be necessary self-diagnostic tests.
in some applications that have steep ramps. However, use caution
Passes Self- Fails Self-Diagnostics
when turning off this option, as increased motor drive failures may
Diagnostics Replace failed circuit.
occur.
Check the current limit setting of the drive motor.

If Correct If Not Correct

Check motor and cables for poor connections. Adjust current limit to
specifications.

Connections Good Connections Cannot

Loose Adjust
Check drive motor
for defect or Repair or See
mechanical tighten loose Problem 54.
drag of drive train. connections.

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PROBLEM 53
Lift truck has long electrical braking distance or sudden (jerk) stop at end of electrical braking cycle. Pump system operation normal.

POSSIBLE CAUSES
Wire #51 defective: current limit set too low: electrical braking diode D5D defective: current sensor defective:
electrical braking current not adjusted properly.

CHECKS
Disconnect current sensor.
Check continuity from P16-1 to P3-7 (wire #2).
Check continuity from P16-2 to P3-8 (wire #42).
Check continuity from P16-3 to P3-6 (wire #85).

Continuity OK Continuity Not OK

Set current limit. Adjust potentiometer P3 to electrical braking specifications if needed. Repair or replace open wires.

Cannot Adjust Adjustment

Check continuity from FWD contactor (wire #51) to logics connection P2-17. corrected
Return truck
to service.

Continuity No Continuity
Check diode D5D for defect. Repair or
replace wire.

OK Defective
Replace logics. Replace diode D5D.

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 SENB8604-02

PROBLEM 54
Current limit and/or electrical braking limit adjustment cannot be made.

POSSIBLE CAUSES
Current sensor defect: motor cables incorrect: logics failure.

CHECKS
Disconnect current sensor.
Check continuity from P16-1 to P3-7 (wire #2).
Check continuity from P16-2 to P3-8 (wire #42).
Check continuity from P16-3 to P3-6 (wire #85).

Continuity OK Continuity Not OK

Check motor cables for proper connections. If not OK, repair. If connections are OK, replace T1D and T2D. Repair or replace open wires.
If replacing T1D and T2D doesn’t fix the problem, replace logics.

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PROBLEM 55
Auxiliary lighting and/or alarm does not function correctly. Lift and drive operations normal.

POSSIBLE CAUSES
Open fuse: faulty wiring: defective switch: shorted load: open load: loss of input voltage to DC-DC converter: defective DC-DC converter.

CHECKS
Is lift truck equipped with a DC-DC converter?

Yes No
Connect the battery and close the key switch. Measure from the
DC-DC converter 12V positive terminal to the 12V negative terminal.

No Voltage Voltage Voltage 11

Voltage above 13V below 11V to 13V
See Chart 55A. See Chart 55B. See Chart 55C. With the faulty auxiliary circuit activated, check for
voltage on the load side of the auxiliary fuse.
Battery Voltage No
Voltage
Check for voltage on the low side of the
Check for
auxiliary switch. short circuits.
Battery Volts 0 Volts Replace
auxiliary fuse.
Check for voltage at the nega- Repair or
tive connection of the load. replace
0 Volts Battery Volts open wire
from fuse
Repair or Repair or or replace
replace open wire replace open defective
from the auxiliary wire from switch.
switch or replace fuse or
the defective replace
auxiliary defective
component. switch.

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 SENB8604-02

PROBLEM 55A
No Voltage Output (See problem 55).

CHECKS
Measure the voltage from (POS INPUT) to (NEG INPUT).

Battery Voltage 0 Volts

Measure the voltage from (12V POS) terminal of the DC-DC converter to Measure the voltage from the battery positive
battery negative. cable at the line contactor to the (NEG INPUT)
terminal of the DC-DC converter.
Battery Voltage 0 Volts
Battery Voltage 0 Volts
Measure the voltage from (ENABLE) terminal of the Replace
the DC-DC Check for open fuse or Repair open
DC-DC converter to battery negative. converter. wiring between the line negative connec-
Battery Voltage 0 Volts contactor and the (POS tion from convert-
INPUT) terminal of the er (NEG INPUT)
Test the fuse at the DC-DC converter for continuity. Repair or
replace open DC-DC converter. to battery
wiring from negative.
Fuse Good Fuse Open the key Open Fuse Open
switch to the
Remove the load connections at the Replace fuse. If (ENABLE) Replace fuse and Wiring
(12VPOS) and (12VNEG) terminals fuse continues terminal of
of the DC-DC converter. to fail, replace check wiring for Repair or
the DC-DC
the DC-DC converter. shorts. If no replace
converter. shorts are found faulty
and the fuse con- wiring.
11 to 13 Volts <11V or tinues to fail,
>13V replace the DC-
Check for a short
circuit in each auxiliary Replace DC converter.
circuit. the DC-DC
converter.

No Shorts Short
Found Found
Replace the Repair or
DC-DC replace
converter. faulty
wiring or
compo-
nents.

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SENB8604-02

PROBLEM 55B
Voltage Below 11 Volts (See problem 55).

CHECKS
Measure the (POS INPUT) or (+IN) terminal to the (NEG INPUT) or (- IN) terminal of the DC-DC converter.

35 Volts or Above Below 35 Volts

Remove all connections at the (12V POS) and the (12V NEG) or the Perform “Battery Load Tests”.
(+OUT) and the (-OUT) terminals of the DC-DC converter. Measure
the voltage from the (12V POS) to (12V NEG) or (+OUT) to (-OUT). Battery Low Battery Good
Below 11 Volts Charge or replace Check all DC-DC converter input connections
11 to 13 Volts battery.
from the battery, fuse, and key switch or relay.
Check for a short or low resistance in DC-DC converter faulty.
the auxiliary circuits and loads. NOTE: Replace converter.
Excessive loading places the converter All Connections Poor
into current limit. (12A maximum) Good Connections
Replace plug-in relay Repair or replace
at the relay printed faulty wiring or
circuit board (if connections.
equipped with a relay).

116
 SENB8604-02

PROBLEM 55C
Voltage above 15 volts (see problem 55).

CHECKS
Remove all connections at the (12V POS) and (12V NEG) or the (+OUT) and the (-OUT) terminals of the DC-DC converter.
Measure the voltage from the (12V POS) to (12V NEG) or (+OUT) to (-OUT).

11 to 13 Volts Above 11 Volts

Check the output load circuits for incorrect wiring or shorts to battery negative. DC-DC converter faulty. Replace converter.

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PROBLEM 56
Slow steering, but pump motor does turn. Drive and lift systems operation normal.

POSSIBLE CAUSES
Steering pressure switch defect: wiring defect: failed logics.

CHECKS
Check the battery, close the seat switch and key switch. Put the direction lever in forward. Disconnect pressure switch connector P24.

Pump Motor Speed Remains The Same. Pump Motor Speed

With P24 disconnected, check for a short circuit between P1-6 (silver area) and battery negative. Increases
Replace the steering
Not Shorted Shorted pressure switch.
Test the head capacitors. Inspect the capacitor wiring to positive and negative Repair or replace
heatsinks. Verify correct torque for capacitor hardware. faulty wiring.

Test OK Test Failed

Replace logics. Replace failed capacitors or repair
connections and wiring.

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 SENB8604-02

PROBLEM 57
Steering idle speed runs fast. Pump motor turns at high power steering speed continuously.
Pump motor runs continuously when neutral is selected (no chat mode).

POSSIBLE CAUSES
Steering pressure switch defect: pressure switch connector disconnected: wiring defect: failed logics.

CHECKS
Check steering pressure switch connector P24 for proper connection.
Connected Disconnected
Disconnect the pressure switch connector P24. Place a jumper wire from P24-1 to P24-2. With the key Connect P24.
switch ON, seat switch closed, and a direction selected, the pump motor should run at slow speed.
Remains at High Speed Runs at Slow Speed
Disconnect the battery and discharge the head capacitors. Check continuity Replace the pressure
from P24-1 to the control panel battery negative. Also check continuity from switch.
P24-2 to logics P1-6 (wire #78).

Continuity No Continuity
Replace logics. Repair or replace open wire.

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SENB8604-02

PROBLEM 58
Travel Speed reduced to 2.0 mph (no code).

POSSIBLE CAUSES
Speed set at 2.0 mph: service or park brake switch out of adjustment or broken: wiring defect.

CHECKS
Run Self Diagnostic.

Failed Passed
Check failed circuit and repair. Check Lift Setup.

Brake Switch Failed

Check adjustment & operation of switch.

OK Not OK
Check wiring to switch. Repair switch and adjust.

Not OK
Check logics.

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 SENB8604-02

PROBLEM 59
Display = “FFFF.O” .

POSSIBLE CAUSES
Display is defective.

CHECKS

Replace Display.

121
SENB8604-02

PROBLEM 60
Display = Code “H” .

POSSIBLE CAUSES
Hydraulic switch closes before turning key switch on.

CHECKS
Adjustment of hydraulic switches.

Adjust or repair as needed.

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 SENB8604-02

PROBLEM 61A
Display = Code “E” (Not Flashing).

POSSIBLE CAUSES
Accelerator depressed before turning key switch on.

CHECKS

Adjust accelerator linkage as needed.

PROBLEM 61B
Display = Code “E” (Flashing) .

POSSIBLE CAUSES
Seat Switch open when it should be closed.

CHECKS
1. Seat Switch.
2. Open in Seat Switch Harness.

CORRECTION
1. Replace Switch.
2. Repair Wires.

123
SENB8604-02

NOTES

124
 SENB8604-02

Systems Operation Discharging Head Capacitor

(HEAD CAP)
and Test Equipment
6V7070 Heavy Duty Digital Multimeter (1) can be used
to measure voltage, resistance or current. When used
! WARNING
to troubleshoot MicroCommand II control panels, Battery voltage and high amperage are present.
8T3224 Needle Tips (5) should be attached to the Injury to personnel is possible. Disconnect the bat-
meter leads. These needle tips have a smaller diameter tery and discharge the head capacitor (HEAD CAP)
and are less likely to cause damage to connectors. See before any contact is made with the control panel.
the enclosed Instructions for the correct operation of
Before servicing truck, always discharge the head
6V7070.
capacitors. The voltage measured across the
8T0900 Clamp-On Ammeter (2) may be used to mea- capacitors should be less than 5 volts. If the capac-
sure current. When using ammeter (2) with 6V7070 itors are not discharged, use the following proce-
Digital Multimeter (1) as a remote readout, 6V6014 dure to discharge them.
Cable (4) should be used to connect ammeter (2) to
multimeter (1). See Special Instructions SEHS8420 for
the correct operation of 8T0900.
Resistor (3) is a 150 ohm, 25 watt resistor used to dis-
charge the head capacitor before contact is made with
the control panel.
4C4029 Trimmer Adjust Tool (6) allows easier adjust-
ment of the adjusting screw found on potentiometers.
The insulated body has a blade on each end. One
blade is recessed to provide a captive screwdriver for
adjustments that are difficult to see. The other end has
an exposed blade to reach adjustment screws that are
behind panels which have small access holes.

2 30703P1
1
1. Disconnect the battery and discharge the head
capacitor.
4
2. Put a 150 Ohm, 25 watt resistor (1), Part No.
3 0358280, in position between the terminals of
head capacitor (2). Hold the resistor in position
for 20 seconds. This will discharge the capacitor
below 5 volts.

Tools.eps
(1)6V7070 Heavy Duty Digital Multimeter
(2) 8TO900 Clamp-On Ammeter (3) 0358280 Resistor
(4) Ammeter 6V6014 Cable (5) 8T3224 Needle Tips
(6) 4C4029 Trimmer Adjust Tool

125
SENB8604-02

Logics Removal Component Tests

! WARNING ! WARNING
Battery voltage and high amperage are present. Battery voltage and high amperage are present.
Injury to personnel is possible. Disconnect the bat- Injury to personnel is possible. Disconnect the bat-
tery and discharge the head capacitor (HEAD CAP) tery and discharge the head capacitor (HEAD CAP)
before any contact is made with the control panel. before any contact is made with the control panel.
1. Disconnect the battery and discharge the head To clean the control panel, use air pressure to blow
capacitor. off dust and dirt. Do not use steam or solvent.
NOTICE: Do not use steam or solvent to clean the
controls. Damage can be caused to the control
panel. Use pressure from an air hose with a maxi
mum pressure of 205 kPa (30 psi) to clean the
control panel when necessary. The air supply must
be equipped with a water filter.
NOTE: When control wires and power cables or
bus bars are to be connected to the same bolt or
stud, place all control wires together on the top of
the bus bar or power cable.
Use the wiring diagram and electrical schematic (locat-
ed inside rear panel cover) to locate components
referred to by name and number in the procedures that
follow. All wires must be located as shown on the
wiring diagram and schematic.

97C54-00301
Component Location 2) Logics cover. (3) Screws.

2. Loosen screws (1) that hold logics cover (2).

3. Remove the logics cover.
4. Disconnect connectors P1, P2 and P3. When
disconnecting connectors, pull on the plastic
connector housing, not on the wires.
5. Loosen screws (3) which hold the logics to
control panel.
6. Remove logics and replace logics cover to
prevent damage.(1)Screws.

Wiring Diagram And Schematic Inside Rear Panel Cover (Example Only)

Logics Connector Removal

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 SENB8604-02

Logic Unit Quick Reference Voltage Check

The chart that follows is a quick reference of the
expected voltages at the logics card pin connectors.
All voltage measurements are made with respect to
battery negatives.

! WARNING
The lift truck can move suddenly. Injury to personnel
or damage to the lift truck is possible. Safely lift the
drive wheels off the floor. Put blocks of wood under
the frame so both drive wheels are free to turn.
Keep away from drive wheels.
1. Put blocks of wood under the frame so both
drive wheels are free to turn.
2. Disconnect the battery and discharge the head
capacitor.
3. Remove the logics cover.
4. Connect the multimeter negative lead to control
panel battery negative.
5. Set the multimeter to the 200 volt DC range.
6. Use the multimeter positive lead with an 8T3224
Needle Tip to measure the voltages under normal
and activated conditions as shown in the Logic
Voltage Checks chart.

Logic Board Layout

127
SENB8604-02

LOGIC VOLTAGE CHECKS

Logic Wire Function *Normal Activated Test Procedure.
Terminal No. Voltage Voltage
P1-1 13 Lift_1 High Low Activated by moving lift lever OFF to full ON.
P1-2 81 Lift_2 High Low Activated by moving lift lever OFF to full ON.
P1-3 89 Tilt High Low Activated by moving tilt lever.
P1-4 88 Aux 1 High Low Activated by moving Aux 1 lever.
P1-5 87 Aux 2 High Low Activated by moving Aux 2 lever.
P1-6 78 Pressure Switch Low High Activated by turning steering wheel.
P1-7 82 Drive BWI High Low Activated by brush wear.
P1-8 83 Pump BWI High Low Activated by brush wear.
P1-9 15 Reverse (without backup alarm) High Low Activate direction lever from NEU to REV.
P1-10 14 Forward High Low Activate direction lever from NEU to FWD.
P1-11 91 Park Brake Switch Low High Activate park brake lever then release.
P1-12 113 Service Brake Switch Low High Activate service brake then release it.
P1-13 7 Seat Switch High Low Activated = switch closed.
P1-14 105 Lift Limit Switch High Low See Note 1.
P1-15 8 Accel PWM 12 to 12.75 1.6 to 2.0 Depress accelerator fully then release.
P1-16 - Not used
P1-17 - Not used
P1-18 115 Drive Motor Speed 1 2.5
P1-19 116 Drive Motor Speed 2 2.5
P1-20 Polarizing Plug
P1-21 1 GND 0 0 Battery / logic card negative.
P2-1 96 Drive SF Control 0 to 1 11 to 12 Activate drive system.
P2-2 92 Drive SF Collector B+ 0 to 1 Activate drive system.
P2-3 72 Pump SF Control 11 to 12 0 to 1 0 - 8 = 11 to 12 9 = 5.5 to 6.25 10 = 0 to 1
P2-4 71 Pump SF Collector 0 to 1 B+ 0 - 8 = 0 to 1 9 = 1/2 B+ 10 = B+
P2-5 31 Drive Armature Control B+ B+ to 0 Volts Activated as drive system runs faster.
B+ to B+
P2-6 37 Drive Emitter 0 to 1 0 to 1 - Activated as drive system runs faster. See Systems
Increasing Operation section, “Drive System Shunt Field Operation.”
to B+
P2-7 79 Pump B Control B+ Activate Pump.
P2-8 117 Pump B0 Control B+ Activate Pump.
P2-9 118 Pump B0 Turn Off Control
P2-10 45 Pump Emitter See Systems Operation section, “Pump System Shunt Field
Operation.”
P2-11 97 D6D (Regen) Anode
P2-12 34 Heatsink
128
 SENB8604-02

Logic Wire Function *Normal Activated Test Procedure.

Terminal No. Voltage Voltage
P2-13 100 Frame
P2-14 101 A1
P2-15 102 A2
P2-16 Polarizing Plug
P2-17 51 Plug
P2-18 119 Pump Shunt +
P2-19 29 Pump Shunt - 0 0
P2-20 106 Brake Fluid Level High Low Activated by low brake fluid level.
P2-21 1 GND
P3-1 76 Drive Thermal Low High Activated by hot drive motor.
P3-2 77 Pump Thermal Low High Activated by hot pump motor.
P3-3 46 Control Thermal Low High Activated by hot control panel. See *
P3-4 12 Display (+) 10.9 to 13.75 10.9 to 13.75 Test with truck in normal state.
P3-5 16 Display (-) 0 to 2.75 0 to 2.75 Test with truck in normal state.
P3-6 85 Current Sensor Supply 7.15 to 7.5 7.15 to 7.5 Test with truck in normal state.
P3-7 2 Current Sensor GND 0 0 Test with truck in normal state.
P3-8 42 Current Sensor Input 3.6 to 4.0 Increasing Activated by current flow in drive circuit.
Output
P3-9 26 Line Contactor B+ See Note 2. B+ = coil open. Pulsed voltage = coil closed.
P3-10 30 Pump Bypass Contactor B+ See Note 2. B+ = coil open. Pulsed voltage = coil closed.
P3-11 35 Drive Bypass Contactor B+ See Note 2. B+ = coil open. Pulsed voltage = coil closed.
P3-12 20 Forward Contactor B+ See Note 2. B+ = coil open. Pulsed voltage = coil closed.
P3-13 19 Reverse Contactor B+ See Note 2. B+ = coil open. Pulsed voltage = coil closed.
P3-14 75 Regen Contactor B+ See Note 2. B+ = coil open. Pulsed voltage = coil closed.
P3-15 Polarizing Plug - -
P3-16 38 Contactor Supply B+ B+
P3-17 38 Contactor Supply B+ B+
P3-18 4 Switched Positive B+ B+
P3-19 - Not Used
P3-20 1 GND 0 0
P3-21 1 GND 0 0

NOTES:
* “Normal” = Battery connected, key switch, seat Low voltage should be 0 to 1 volt.
switch, park brake switch and line contactor closed. 1. Depending upon Option #10, voltages could be
reversed.
High voltage should be 14 to 16 volts. *Hi voltage
2. Battery voltage minus the voltage drop across
is 14v without line contactor and 22v with Line
the contactor (18 to 28 volts).
contactor in.

129
SENB8604-02

Conductor And Switch Capacitor Test, then each capacitor must be discon-
nected and tested separately. The failed individual
Continuity Tests capacitors must be replaced.
1. Set the multimeter to the 200 Ω range. 1. Disconnect the battery and discharge the head
2. Use the multimeter to perform the continuity test. capacitor.
If continuity exists, the measurement will be less 2. Visually inspect the capacitor for bulges at the
than 1 ohm. If the measurement is more than terminals.
this, continuity does not exist and the problem
will have to be repaired. 3. Verify the plastic top is not melted around the
terminals and that the blow plug is not leaking.
Accelerator Control
! WARNING
! WARNING Head Capacitor “blow plug” will rupture with
Battery voltage and high amperage are present. reverse polarity. Vapors and contents of Head
Injury to personnel is possible. Disconnect the bat- Capacitors are toxic, flammable and corrosive.
tery and discharge the head capacitor (HEAD CAP) Personal injury can be caused from breathing the
before any contact is made with the control panel. fumes or if its contents make contact with the skin.
Be sure to always connect the positive wire from
the positive heatsink to the positive terminal of the
Head Capacitor.
4. Disconnect positive cable (2) from the positive
heatsink connection point (1).
5. Set the multimeter to the 20KΩ range. Connect
the multimeter positive lead to positive side (5) of
head capacitor (3). Connect the multimeter
negative lead to negative side (4) of head
capacitor (3).
6. The meter must increment to above 10,000
ohms. Replace the capacitor if the indication is
not correct.
See Head Capacitor in Specifications Section for proper
P9 Connector Location (Under Floor Plate (1)P9 connector
(2) Accelerator control assembly order of the head capacitor connections and
bolt torque specifications.
Refer to “Self Diagnostics” Accelerator Control in
Troubleshooting section. 1

Capacitor (HEAD)

! WARNING 3

Battery voltage and high amperage are present.

Injury to personnel is possible. Disconnect the bat-
tery and discharge the head capacitor (HEAD CAP) - +
2
before any contact is made with the control panel.
NOTICE: Damage can be caused to the head
capacitor. Do not remove bolts from capacitors to
4
perform tests. Remove capacitor connecting cables
at heatsink connections.
Location Of Components (1) Positive heatsink connection point (2)Head
On these trucks, head capacitor refers to all the head Capacitor (3) Negative side of capacitor (4) Positive side of Capacitor
capacitors hooked together as installed in the control
panel. If the capacitors hooked together fail the Head

130
 SENB8604-02

Contactor Coil Suppression For Line, Bypass, and

Pump Contactors
Bypass Activation
! WARNING
! WARNING Battery voltage and high amperage are present.
The lift truck can move suddenly. Injury to person- Injury to personnel is possible. Disconnect the
nel or damage to lift truck is possible. Safely lift the battery and discharge the head capacitor (HEAD
drive wheels off the floor. Put blocks of wood under CAP) before any contact is made with the control
the frame so both drive wheels are free to turn. panel.
Keep away from drive wheels that turn. The coil suppression diode for the line, bypass, pump,
NOTE: Damage can be caused to the control panel. and regen contactors is built into the logics. To check
Do not switch the direction lever from one direction the suppression diode, use the following procedure:
to the other (plug the lift truck) when the drive 1. Disconnect the battery and discharge the Head
wheels are off the ground and in rotation at full Capacitor.
speed.
2. Remove the logics cover.
1. Connect the battery and close the seat switch.
3. Remove connector P3 from the logics board.
2. Turn the key to ON and release the parking
brake. 4. Set the multimeter to the diode test position.
3. Select a direction and rapidly depress the 5. Connect the negative multimeter lead to logics
accelerator pedal all the way to the floor. board P3-17.
4. Measure and record the time it takes the bypass 6. Connect the positive multimeter lead to logics
contactor to close. This should be.5 to 4.5 board:
seconds after the accelerator is fully depressed.
P3-9 for line contactor
5. If the recorded value from step 4 is less than.5 P3-11 for bypass contactor
seconds, the logics may need to be replaced. P3-10 for pump contactor
(During normal operation this time will vary with P3-14 for regen contactor
the load on the truck and width the value set in
7. The multimeter must indicate .3 to .9 volts.
option #8 of the programmable features. See the
topic “Programmable Features” in the Systems 8. Reverse the leads. The meter must indicate OL.
Operation section.)
9. If either test fails, replace the logics.
6. If the recorded value from step 4 is more than
4.5 seconds, check the bypass contactor tips for
free movement. Check wiring for bad connec
tions. Also check for drive train drag and the
current limit setting (potentiometer P1).
NOTE: The bypass contactor will not close if the
accelerator linkage is not adjusted correctly.

C0000 Logics Board

131
SENB8604-02

Coil Suppression For Direction Contactors Coil Pulsing

The coil suppression diode for the direction contactors 1. Disconnect the battery and discharge the head
is built into the logics, but is different from the other capacitor.
contactors. To check the suppression diode, use the
2. With the contactor coil leads and suppression
following procedure:
assembly leads connected, set the multimeter to
1. Disconnect the battery and discharge the head the 200 volt DC range.
capacitor.
3. Connect the multimeter negative lead to the
2. Remove the logics cover. negative coil terminal Y and the meter positive
lead to the coil positive terminal X wire #38.
3. Remove connector P3 from the logics board.
4. Connect the battery and activate the controls
4. Set the multimeter to the diode test position.
necessary for the contactor to be activated.
5. Connect the negative multimeter lead to logics
5. After the contactor activates the multimeter
board P3-17.
must indicate 15 to 30 volts. If the voltage is
6. Connect the positive multimeter lead to logics not correct and the contactor passed the Coil
board: Suppression test and the Coil Resistance test,
the logics must be replaced.
P3-12 for forward contactor
P3-13 for reverse contactor Contactor Tips
7. The multimeter must indicate OL. 1. Disconnect the battery and discharge the head
capacitor.
8. Reverse the leads. The meter must indicate OL.
2. Visually inspect the tips to verify they are not
9. If either test fails, replace the logics.
welded, melted, burned or pitted.
3. Press and release the tips quickly to verify there
is not binding.
4. Visually inspect the contactor assembly. Verify
foreign objects don’t interfere with normal
contactor operation.
NOTE: Perform a contactor tip gap check on
direction contactors only.
5. Check contactor tip gap with a feeler gauge as
shown. Refer to Specifications section for correct
settings.

C0000 Logic Board Layout

Coil Resistance
1. Disconnect the battery and discharge the head
capacitor.
2. Disconnect all leads to the X and Y terminals of
the coil.
3. Set the multimeter to the 200 KΩ range.
4. Measure the resistance of the coil at the X and Y
terminals. It must be within specifications. See Checking Contactor Tip Gap
Component Measurements in the Specifications
section.
5. If the coil is not within specifications, the
contactor assembly will have to be replaced.

132
 SENB8604-02

DC /DC Converter 1. Disconnect the battery and discharge the head

capacitor.
Refer to Problem 55 in the Troubleshooting section.
2. Remove the logics.
Diodes
3. Disconnect the cathode and remove the diode.
! WARNING 4. Wipe contact surface of the diode (1) clean. Put
Battery voltage and high amperage are present. a small amount of 5P8937 or 5P9810 Thermal
Injury to personnel is possible. Disconnect the bat- Joint Compound on contact surfaces (1), but not
tery and discharge the head capacitor (HEAD CAP) on the threads.
before any contact is made with the control panel. 5. Install the diode and tighten to the specification
NOTE: The following test procedure can be applied listed in the following chart:
to diode D4P, D4D and D5D. Diode D5D will be used
in the following examples. Diode Torque
1. Disconnect the battery and discharge the head D4D, D5D 36 N•m (320 lb in)
capacitor.
D4P 13 N•m (16 lb in)
2. Disconnect the D5D cathode lead wire (5).
6. Connect all wires that were removed.
3. Set the multimeter to the diode test position.
4. Connect the negative multimeter lead on D5D
cathode lead wire (5). Connect the positive
multimeter lead to battery negative (7). The
multimeter should indicate .3 to .9 volts.
5. Reverse the multimeter leads. The multimeter
should indicate OL. If any of the measurements
are not correct, replace the diode.

C25486P1
Diode Installation (Typical example)
(1) Contact surfaces

Vehicle Monitoring System

The display panel performs a lamp test during power
up. All segments and LEDs should light for three
seconds.

97C54-00300
1)D4P Cathode lead wire 2) D4P 3)D4D cathode lead wire
4)D4D 5)D5D Cathode lead wire 6)D5D 7) Battery Negative

Diode Replacement

! WARNING P6 Harness Connector Contact Layout (end view)

Battery voltage and high amperage are present.

Injury to personnel is possible. Disconnect the bat-
tery and discharge the head capacitor (HEAD CAP)
before any contact is made with the control panel.

133
SENB8604-02

Driver Board Tests

Drive Driver Board

B
A

Driver Board Terminal Connections(A) P12 Connector(B) B Terminals(C) BO Terminals

Pump Driver Board

B
A

(A)P4 Connector (B)B Terminals (C)BO Terminals

134
 SENB8604-02

Driver Board Testing

Use the following charts for testing the driver boards (36/48/72/80V):
Drive Driver Board Tests
Component Multimeter Range + Lead - Lead Results
T314/T315 (B to E) 200Ω P12-15 P12-16 3.7 to 4.1Ω
R311 P12-16 P12-15 3.7 to 4.1 Ω
T314/T315 (B to C) Diode B P12-15 OL
P12-15 B 0.3 to 0.9
T314/T315 (C to E) Diode B P12-16 0.3 to 0.9
Z313 P12-16 B OL
BO Balance 200Ω BO BO 0 to 0.5 Ω
D311, R313 200Ω P12-14 B 4.5 to 7.5 Ω
B P12-14 4.5 to 7.5 Ω
R315, R316, R317 2 KΩ P12-14 P12-5 .315 to .350 kΩ
P12-5 P12-14 .315 to .350 kΩ
Pump Shunt Field Components
Pump SF Fuse 200Ω P12-1 P12-2 0 to 0.5
D351 Diode P12-2 P12-6 OL
P12-6 P12-2 0.3 to 0.9
T351 (D to S) Diode P12-6 P12-10 OL
P12-10 P12-6 0.3 to 0.9
T351 (G to S) 2 KΩ P12-8 P12-10 1.71 kΩ to 1.89
R351, C351, Z351 P12-10 P12-8 kΩ1.71 kΩ to 1.89 kΩ
T 351 (G to S) Diode P12-8 P12-10 First reading should be OL. First reading should be greater
R351, C351, Z351 P12-10 P12-8 than second reading. Neither reading should be less than 0.5

Drive Shunt Field Components

Drive SF Fuse 200Ω P12-3 P12-4 0 to 0.5
D371 Diode P12-4P12-7 P12-7P12-4 OL
0.3 to 0.9
T371 (D to S) Diode P12-7 P12-10 OL
P12-10 P12-7 0.3 to 0.9
T371 (G to S) 2 KΩ P12-9 P12-10 1.71 kΩ to 1.89 kΩ
R371, C371, Z371 P12-10 P12-9 1.71 kΩ to 1.89 kΩ
T371 (G to S) Diode P12-9 P12-10 First reading should be OL. First reading should be greater
R371, C371, Z371 P12-10 P12-9 than second reading. Neither reading should be less than 0.5.

135
SENB8604-02

Pump Driver Board Tests

Component Multimeter Range + Lead - Lead Results
R329, R330 2 KΩ P4-1 P4-5 1.375 to 1.525 kΩ
R328, C322 P4-5 P4-1 1.375 to 1.525 kΩ
Z324, T327 (G to S)
R339, R340 2 KΩ P4-2 P4-5 .798 to .882 kΩ
R338, C332 P4-5 P4-2 .798 to .882 kΩ
Z334, T337 (G to S)
T337 (G to D) Diode P4-2 P4-7 OL
P4-7 P4-2 0.5 to OL
T327 (G to D) Diode P4-1 P4-7 OL
P4-7 P4-1 0.5 to OL
T337 (D to S) Diode P4-7 P4-10 0.5 to 1.1
R332 P4-10 P4-7 OL
T327 (D to S) Diode P4-7 P4-3 0.5 to 1.1
R332 P4-3 P4-7 OL
T341 (B to C) Diode P4-7 P4-4 0.3 to 0.9
R343, R342 P4-4 P4-7 OL
T341 (B to E) 200 Ω P4-4 BO* 37.9 to 41.9Ω For 72/80V 79.9 to 83.9 Ω
R343, R342, R341 BO P4-4 37.9 to 41.9 Ω 79.9 to 83.9 Ω
*
T341 (C to E) Diode P4-7 BO 0.3 to 0.9
*
BO P4-7 OL
*
T331/ T332 (B to E) 200 Ω P4-5 P4-10 2.84 to 3.29 Ω
R331 P4-10 P4-5 2.84 to 3.29 Ω
T331 / T322 (B to C) Diode P4-10 BO* OL
BO* P4-10 0.3 to 0.9

T 331 / T332 (C to E) Diode P4-5 BO* OL

BO* P4-5 0.3 to 0.9
T324 (B to E), R321 200 Ω P4-5 P4-3 2.84 to 3.29 Ω
P4-3 P4-5 2.84 to 3.29 Ω
T324 (B to C) Diode P4-3 B** OL
B** P4-3 0.3 to 0.9

T324 (C to E) Diode P4-5 B** OL

Z 323 B** P4-5 0.3 to 0.9

D321 Diode P4-7 B 0.3 to 0.9

**
B** P4-7 OL

R327 200 Ω B** BO* 0.5 to 2 Ω

BO B 0.5 to 2 Ω
* **
*Test BO terminals on both transistors.
**Test B terminals on both transistors.

136
 SENB8604-02

Traction Motor Current Sensor Test 9. Move the direction selection lever to forward and
depress the accelerator. The voltage being
measured should increase. If the voltage
! WARNING decreases, the current sensor is mounted
backward. If there is no voltage measured or the
Battery voltage and high amperage are present. voltage being measured does not change, the
Injury to personnel is possible. Disconnect the bat- current sensor must be replaced.
tery. The head capacitor (HEAD CAP) must be dis-
charged before any contact with the control panel
is made. Disconnect the battery and discharge the
HEAD CAP.
1. Disconnect the battery, discharge the head
capacitors, and remove the logic cover.
2. Disconnect current sensor connector P16.
3. Check continuity from harness connector P16-3
(wire #85) to logics P3-6 and connector P16-2
(wire #42) to logics P3-7. Check for short
between harness the connector P16-3 wire #85
and the control panel battery negative. Check for
short between the harness connector P16-2 (wire
#42) and the control panel battery negative.
Repair or replace any defective wires.

! WARNING
The lift truck can move suddenly. Injury to person-
nel or damage to the lift truck is possible. Safely lift
the drive wheels off the floor. Put blocks of wood
under the frame so both drive wheels are elevated
and free to turn. Keep your person away from the
drive wheels that turn.
4. Set the multimeter to the 20V DC range. With the
connector P16 reconnected, connect the multi-
meter positive lead to logics P3-6. Connect the
multimeter negative lead to the control panel bat-
tery negative.
5. Connect the battery and turn the key ON. The
measurement must be 7.15 to 7.50 volts.
Connect the multimeter positive lead to logics
P3-8. The measurement must be 3.6 to 4.0 volts.
If both measurements are not correct, replace
the logics.
6. Disconnect the battery and discharge the head
capacitors.
7. Set the multimeter to the 20V DC range and
connect the multimeter positive lead to logics
P3-8. Connect multimeter negative lead to the
control panel battery negative.
8. Connect the battery and turn the key ON. The
measurement must be 3.6 to 4.0 volts.

137
SENB8604-02

Hydraulics
The instrument panel is also powered at this time.
NOTE: On these circuit diagrams shaded lines Current will flow through the key fuse, P5-3, key
illustrate current flow. switch, wire #4,
Actuation Circuit P6-2, and P6-1 back to battery negative. The display
This circuit supplies power to the MicroCommand II first does a “lamp test” which will light all the LED sym-
and the monitoring system instrument panel. It must be bols and LCD segments for 5 seconds. The hour meter
activated before power steering, hydraulics, or drive will readings are then indicated.
operate. The logics will start to perform a set of “Run-Time” diag-
When the battery is connected and the key switch is nostics checks. The letter “E” will flash on the display
closed, current flows from battery positive through the indicating the key is ON with no operator in the seat.
key fuse, key switch, wire #4, P5-4 to the logics con- When the seat switch is closed, current will flow from
nection P3-18. The logics connection to battery nega- the logics to P1-13 through P5-7 (the seat switch) to
tive is at P1-21, P2-21, P3-20 and P3-21. The logics battery negative. The logics then activates the line
circuits are powered up to accept voltage inputs and contactor coil and P3-9 back to battery negative.
create voltage outputs whenever the battery is
connected and the key is ON.

3
3
LIGHTS FUSE 15A
34
P12-13
KEY FUSE 10A 3 HORN BUTTON
P12-11 P12-12 3 P5-3 P46-2 4 P46-1
R319 R320 KEY SWITCH
P3-18 P5-4 4

P3-4 P5-12 12 P6-4 P6-2 4

DISPLAY
46

34 P3-5 P5-16 16 P6-3 P6-1 1

P2-12 LIFT LIMIT SW
P3-3 SEAT OPERATED BRAKE SW
P1-14 127 P5-21 P60-C P60-A
100 1 +
P2-13
SEAT SWITCH 1
P1-13 P5-7 7 1 HORN
2
PUMP MOTOR THERMOSTAT -
P3-2 77 P5-25 1

P3-1 76 P5-24 1
DRIVE MOTOR THERMOSTAT SERVICE BRAKE SWITCH 3
P1-12 P5-23 113 P40-C P40-B 1

P1-11 P5-19 91 1
PARK BRAKE SW BRAKE FLUID SWITCH
P2-20 P5-22 106 P33-2 P33-1

FWD
P1-10 P5-14 14 P7-B 4
DIR SW P7-A 1
34 REV
P1-9 P5-15 15 P7-C
39 P3-17
LINE COIL
XY 26 P3-9 FWD
P61-2
LIFT COIL P61-1 1
X Y 30 P3-10 FOOT DIR SW
REV
BYPASS COIL P38-8 P61-3
LOGICS

XY 35 P3-11
FWD COIL
P1-1 P5-13 13 P13-5 1
XY 20 P3-12
REV COIL LIFT 1 SW
XY 19 P3-13 P1-2 P5-27 81 P13-6 1 4
REGEN COIL LIFT 2 SW
XY 75 P3-14
3 P1-3 P5-34 89 P13-2 1 P32-3 1

38 P3-16 TILT SW
P32-4 3
LINE FUSE P1-4 P5-33 88 P13-3 1
2 TO 3 TON AUX 1 SW 4
36/48 VOLT
675 AMP P1-5 P5-32 87 P13-4 1 P13-1
600 AMP
1TON AUX 2 SW
P1-6 P5-26 78 P24-2 P24-1 1 1
LINE TWISTED PAIR TWISTED PAIR
CTR PRESSURE SWITCH
P1-19 116 P5-31 P52-2
SPEED
SENSOR
P1-18 115 P5-30 P52-1 SWITCH 1 1 4 1
BATTERY
36/48 VOLT P1-15 8 P5-8 P9-C P9-A
OR P9-B
72/80 VOLT ACCEL
CONTROL
P3-21

P1-21
P3-20
P2-21

P5-36

P5-37
P5-2

P5-1

2EC1513

138
 SENB8604-02

Capacitor Charging Circuit 3

34
With the line contactor tips closed, the logics continues
its checks for any “Run Time” faults. If no faults are P12-13
KEY FUSE 10A
detected, the display will indicate the battery charge P12-11
R319 R320
level, the power steering system operates, the pump
and drive power circuits receive battery voltage and the
34
logics receives battery voltage on wire #34 at P2-12. P2-12

A charging resistor is used to maintain voltage on the 34

head capacitor whenever the battery is connected and
the line contactor is open. This voltage reduces arcing
3
of the line contactor tips during line contactor activa-
39 P3-17
tion. The charging resistor is installed parallel with the LINE FUSE LINE COIL
2 TO3 TON XY 26 P3-9
line contactor tips. Current flows from battery positive 36/48 VOLT LIFT COIL
675 AMP
through the key fuse, charging resistor, line fuse and 600 AMP
1 TON
X Y 30
BYPASS COIL
P3-10

the positive heat sink into battery negative. This circuit XY 35 P3-11

LOGICS
LINE FWD COIL
will maintain a voltage across the head capacitor above CTR XY 20 P3-12
REV COIL
approximately 20 volts. XY 19 P3-13
REGEN COIL
XY 75 P3-14
BATTERY
36/48 VOLT HEAD
OR CAP 38 P3-16
72/80 VOLT

P3-21
1

Capacitor Charging Circuit (Typical Example)

139
SENB8604-02

Hydraulic Pump Motor Circuit

Only one hydraulic pump motor is used for all power
steering, lift, tilt, and auxiliary hydraulic functions. To
activate the pump circuit, the seat switch, key switch
and line contactor must be closed first as explained in
the topic, Actuation Circuit. The power steering, lift, tilt,
and auxiliary circuits are explained as follows:

140
 SENB8604-02

Power Steering Circuit with an oscilloscope. During steering, when this signal
is high, it indicates that the transistors should be off.
The power steering (PS) circuit has two speeds: PS Idle When this signal is low, it indicates that the transistors
and PS Boost-up. should be on. When this signal goes low, current flows
NOTE: Shaded lines on the circuit diagrams indicate down through R338, R339, and R340. These resistors
current flow. Other circuits can be activated at the form a voltage divider that starts to reduce the voltage
same time, but each one is shown separately to on the gate of T337. It does not reduce immediately,
illustrate current flow in each individual circuit. due to capacitor C332. Also, it will not drop further
than about 7V below battery positive because of Z334.
Power Steering Idle Since no current is flowing in T337, its source is held at
battery positive by R331 and R332. T337 is a P-chan-
After the line contactor closes, the logics generates a
nel mosfet. A P-channel mosfet is a voltage controlled
pulsing signal on P2-8 (Wire #117). This signal oscil-
device that will turn on when the gate voltage is 5V less
lates (moves) between battery negative and battery
than the source voltage. When voltage on the gate of
positive at 15,000 times each second. This is faster
T337 becomes 5V less then its source, T337 turns on.
than can be seen on a voltmeter and must be viewed

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332

R330 34
D321

P2-12
T337

B B
T331

T332

T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13
R340 R339

T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1515

141
SENB8604-02

When T337 turns on current flows from BAT+ through When T331 and T332 turn on, current flows through
the emitter/base junction of T331 and T332 through T331 and T332, through the B0/emitter junction of the
R332 through T337 to the emitter of T1P and T2P. power transistors T1 P and T2P through the pump
Because T331 and T332 are PNP transistors, the cur- armature/series field to BAT-. Since T1 P and T2P are
rent flow through the emitter/base junction causes NPN transistors, the current flow through the B0/emit-
them to turn on. ter junction causes the second stage transistor in T1 P
and T2P to turn on. Now when T337 is on, T331, T332,
When T337 is on, T331 and T332 are on. When T337 is
T1P (second stage), and T2P(second stage) are on.
off, T331 and T332 are off.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332
R330 34
D321

P2-12
T337

B B
T331

T332

T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13
R340 R339

T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1516

142
 SENB8604-02

When the second stage transistor of T1 P and T2P turn during steer idle. During steer idle P2-8 is low about
on, current flows from BAT+ through the second stage 6% of the time, which means T1P and T2P are on 6%
of T1 P and T2P, through the pump armature/series of the time. This results in about 6% of battery voltage
field to BAT-. This causes the pump to turn. So when being applied to the armature during steer idle. This
P2-8 (Wire #1 17) is low, the second stage of the number will not be exactly 6% because the T1 P and
power transistors T1 P and T2P is also on. The logic T2P “ON” time is adjusted by the logics (via P2-8) to
controls this ‘low” time on P2-8 to control the pump help offset changes in battery voltage.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332
R330 34
D321

P2-12
T337
B B
T331

T332

T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13
R340 R339
T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1517

143
SENB8604-02

Additional Information:
Only the second stage transistor of T1P and T2P is These transistors are slow in switching and also suffer
used during steer idle and steer boost-up because of from a problem called “storage time,” which causes
the speed at which these transistors are pulsed. The them to stay on for a short period of time even after
transistors are pulsed at 15,000 Hz (cycles per second) the base/emitter drive is removed. Using only the sec-
to help reduce audible whine that used to exist on ond stage of the power transistors reduces both the
older style trucks during steer idle and boost up. On switching time and the ‘storage time” to acceptable
these systems the transistors were pulsed at 187.5 Hz, values for use at 15,000 Hz pulsing. When only the
which was audible and bothersome to some operators. second stage of the transistors is used, the power tran-
Moving this pulsing frequency to 15,000 Hz has made sistors cannot carry as much current. But this is
the noise both quieter and much more difficult to hear acceptable because the transistors are driven this way
because it is outside the range of human hearing. To only in steer idle and boost up, where the current
accomplish this, it was necessary to speed up the required is not too high.
switching of pump power transistors T1P and T2P.

P4-5
C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332

R330 34
D321

P2-12
T337

B B
T331

T332

T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13
R340 R339

T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1518

144
 SENB8604-02

Hydraulic Pump Shunt Field Circuit

At the same time the logics is pulsing the pump arma- through the pump shunt field fuse, through the pump
ture circuit, a constant voltage (about 12V) is being shunt field, through T351, to BAT-. When the pump
supplied from the logics P2-3 to the gate of T351. shunt field is on 100%, it is at maximum strength.
T351 is an N-channel mosfet, which will turn on when During the power steering speeds, the pump shunt
the gate is 5V greater than the source. Since we have field adds to the motor torque, making it a very power-
applied 12V (which helps insure that T351 is fully on), ful motor at low rpm. The motor during power steering
T351 is on. With T351 on current can flow from BAT+, idle is turning at about 200 rpm.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46

R331

R332
R330 34
D321

P2-12

T337
B B
T331

T332

T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13

T R341 R340 R339

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1519

145
SENB8604-02

Power Steering In Use

If the steering wheel is turned, hydraulic pressure increase the duty cycle applied to T1P and T2P with
increases, and a pressure switch located in the steering the signal on P2-8. Increasing the duty cycle on T1P
gear load sensing line will open. This causes the volt- and T2P increases the voltage applied to the arma-
age at logics connector P 1 -6 to change from a LOW ture/series field, which increases the speed of the
to a HIGH signal. When a HIGH signal is present, the motor and therefore the flow provided to the steer gear.
logics knows that more hydraulic flow is required When the pressure switch is open, the pump motor
because the operator is steering the truck. It will speed will be about 500 rpm.

3
3
LIGHTS FUSE 15A
34
P12-13
KEY FUSE 10A 3 HORN BUTTON
P12-11 P12-12 3 P5-3 P46-2 4 P46-1
R319 R320 KEY SWITCH
P3-18 P5-4 4

P3-4 P5-12 12 P6-4 P6-2 4

DISPLAY
46

34 P3-5 P5-16 16 P6-3 P6-1 1

P2-12 LIFT LIMIT SW
P3-3 SEAT OPERATED BRAKE SW
P1-14 127 P5-21 P60-C P60-A
100 1 +
P2-13
SEAT SWITCH 1
P1-13 P5-7 7 1 HORN
2
PUMP MOTOR THERMOSTAT -
P3-2 77 P5-25 1

P3-1 76 P5-24 1
DRIVE MOTOR THERMOSTAT SERVICE BRAKE SWITCH 3
P1-12 P5-23 113 P40-C P40-B 1

P1-11 P5-19 91 1
PARK BRAKE SW BRAKE FLUID SWITCH
P2-20 P5-22 106 P33-2 P33-1

FWD
P1-10 P5-14 14 P7-B 4
DIR SW P7-A 1
34 P1-9 15 REV
P5-15 P7-C
39 P3-17
LINE COIL
XY 26 P3-9 FWD
P61-2
LIFT COIL P61-1 1
X Y 30 P3-10 FOOT DIR SW
REV
BYPASS COIL P38-8 P61-3
LOGICS

XY 35 P3-11
FWD COIL
P1-1 P5-13 13 P13-5 1
XY 20 P3-12
REV COIL LIFT 1 SW
XY 19 P3-13 P1-2 P5-27 81 P13-6 1 4
REGEN COIL LIFT 2 SW
XY 75 P3-14
3 P1-3 P5-34 89 P13-2 1 P32-3 1

38 P3-16 TILT SW
P32-4 3
LINE FUSE P1-4 P5-33 88 P13-3 1
2 TO 3 TON AUX 1 SW 4
36/48 VOLT
675 AMP P1-5 P5-32 87 P13-4 1 P13-1
600 AMP
1 TON AUX 2 SW
P1-6 P5-26 78 P24-2 P24-1 1 1
LINE TWISTED PAIR TWISTED PAIR
CTR PRESSURE SWITCH
P1-19 116 P5-31 P52-2
SPEED
SENSOR
P1-18 115 P5-30 P52-1 SWITCH 1 1 4 1
BATTERY
36/48 VOLT P1-15 8 P5-8 P9-C P9-A
OR P9-B
72/80 VOLT ACCEL
CONTROL
P3-21

P1-21
P3-20
P2-21

P5-36

P5-37
P5-2

P5-1

2EC1520

146
 SENB8604-02

Flyback Circuit
D4P is a flyback diode for the hydraulic pump motor field/armature goes through PS2, Pump Shunt, D4P,
circuit. Because the series field/armatures on the pump PA1, and back to the series field/armature. When T1P
motor are inductors they need a path for the current to and T2P are pulsing, the flyback circuit causes the
flow when T1P and T2P are turned off. When T1P and average pump motor current to be greater than the
T2P are turned OFF, all the current flowing in the series average battery current flowing through T1P and T2P.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46

R331

R332
R330 34
D321

P2-12

T337
B B
T331

T332
T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13

R340 R339
T R341

T341 1

P4-7
P4-2
R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1521

147
SENB8604-02

Lift Circuit HYDRAULIC PUMP MOTOR SPEED CHART

PUMP ARMATURE SHUNT FIELD PUMP
Lift Control Circuit SPEED DUTY CYCLE DUTY CYCLE CONTACTOR
The 2EC15 family of lift trucks is equipped with a two- 0 0% 100% Off
speed lift system. The system is controlled by two
microswitches that work off of the lift spool on the 1 15 100% Off
main hydraulic valve. As the lift lever is pulled back, Lift 2 20 100% Off
Switch 1 is depressed, which causes the signal on
Logic Connector P1-1 to go from HIGH to LOW. This 3 25 100% Off
signals the logics to run the pump motor at the speed 4 35 100% Off
set for LIFT1 SPEED. As the lift lever is pulled back
further, Lift Switch 2 is depressed, which causes the 5 45 100% Off
signal on Logic Connector P1-2 to go from HIGH to
6 55 100% Off
LOW. This signals the logics to run the pump motor at
the speed set for LIFT2 SPEED. When the operator 7 70 100% Off
releases the lever or pushes the lever forward to lower
8 0 (Bypass) 100% On
a load, both Lift Switches are released. Options 2 and
3 in the setup mode determine at what speed the 9 0 (Bypass) 50% On
pump will run when the lift switches are depressed.
10 0 (Bypass) 0% On
The chart to the right shows the possible speeds:
If the operator pulls back on the lift lever rapidly, the
logics will smoothly ramp up to LIFT2 SPEED in about
1/2 second.

148
 SENB8604-02

Lift Power Circuit

When any hydraulic lever is activated (Lift, Tilt, Aux1, or system described in the power steering system opera-
Aux2), the logics stop using the control output P2-8 tion, we cannot use this system during the heavy cur-
(Wire #117) to control the pump. Because of the rents involved with the lift system. The lift system is
current limitation of the 15,000 Hz pump control operated at 187.5 Hz and controls the B terminal of the
power transistor.

3
3
LIGHTS FUSE 15A
34
P12-13
KEY FUSE 10A 3 HORN BUTTON
P12-11 P12-12 3 P5-3 P46-2 4 P46-1
R319 R320 KEY SWITCH
P3-18 P5-4 4

P3-4 P5-12 12 P6-4 P6-2 4

DISPLAY
46

34 P3-5 P5-16 16 P6-3 P6-1 1

P2-12 LIFT LIMIT SW
P3-3 SEAT OPERATED BRAKE SW
P1-14 127 P5-21 P60-C P60-A
100 1 +
P2-13
SEAT SWITCH 1
P1-13 P5-7 7 1 HORN
2
PUMP MOTOR THERMOSTAT -
P3-2 77 P5-25 1

P3-1 76 P5-24 1
DRIVE MOTOR THERMOSTAT SERVICE BRAKE SWITCH 3
P1-12 P5-23 113 P40-C P40-B 1

P1-11 P5-19 91 1
PARK BRAKE SW BRAKE FLUID SWITCH
P2-20 P5-22 106 P33-2 P33-1

FWD
P1-10 P5-14 14 P7-B 4
DIR SW P7-A 1
34 P1-9 15 REV
P5-15 P7-C
39 P3-17
LINE COIL
XY 26 P3-9 FWD
P61-2
LIFT COIL P61-1 1
X Y 30 P3-10 FOOT DIR SW
REV
BYPASS COIL P38-8 P61-3
LOGICS

XY 35 P3-11
FWD COIL
P1-1 P5-13 13 P13-5 1
XY 20 P3-12
REV COIL LIFT 1 SW
XY 19 P3-13 P1-2 P5-27 81 P13-6 1 4
REGEN COIL LIFT 2 SW
XY 75 P3-14
3 P1-3 P5-34 89 P13-2 1 P32-3 1

38 P3-16 TILT SW
P32-4 3
LINE FUSE P1-4 P5-33 88 P13-3 1
2 TO 3 TON AUX 1 SW 4
36/48 VOLT
675 AMP P1-5 P5-32 87 P13-4 1 P13-1
600 AMP
1 TON AUX 2 SW
P1-6 P5-26 78 P24-2 P24-1 1 1
LINE TWISTED PAIR TWISTED PAIR
CTR PRESSURE SWITCH
P1-19 116 P5-31 P52-2
SPEED
SENSOR
P1-18 115 P5-30 P52-1 SWITCH 1 1 4 1
BATTERY
36/48 VOLT P1-15 8 P5-8 P9-C P9-A
OR P9-B
72/80 VOLT ACCEL
CONTROL
P3-21

P1-21
P3-20
P2-21

P5-36

P5-37
P5-2

P5-1

2EC1522

149
SENB8604-02

When a hydraulic lever is activated, the logics senses down through R328, R329, and R330. These resistors
this through the hydraulic switches and stops using form a voltage divider that starts to reduce the voltage
control output P2-8 (Wire #117) to control the pump. It on the gate of T327. It will not drop further than about
begins to use control output P2-7 (Wire #79). The log- 7V below battery positive because of Z324. Since no
ics generates a 187.5 Hz pulsing signal on P2-7. This is current is flowing in T327, its source is held at battery
faster than ran be seen on a voltmeter and must be positive by R321 and R322. T327 is a P-channel mos-
viewed with an oscilloscope. During hydraulic func- fet. A P-channel mosfet is a voltage controlled device
tions, when this signal is low, it indicates the power that will turn on when the gate voltage is 5V less than
transistors T1P and T2P should be on. When this signal the source voltage. When the voltage on the gate of
is high, it indicates the power transistors T1P and T2P T327 becomes 5V less than its source, T327 turns on.
should be off. When this signal goes low, current flows

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332

R330 34
D321

P2-12
T337

B B
T332

T2P P3-3
T1P

P8-1
R327

T331

B0 B0 100 P2-13
R340 R339

T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1523

150
 SENB8604-02

When T327 turns on, current flows from BAT+ through T324 is a PNP transistor, the current flow through the
the emitter 1 base junction of T324, through R322, emitter/base junction causes it to turn on. When T327
through T327 to the emitter of T1 P and T2P. Because is on, T324 is on. When T327 is off, T324 is off.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46

R331

R332
D321 R330 34
P2-12

T337
B B

T332
T2P P3-3
T1P

P8-1
R327

T331
B0 B0 100 P2-13

R340 R339
T R341

T341 1

P4-7

P4-2
R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21
71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1524

151
SENB8604-02

When T324 turns on, current flows through T324, current flow through the B/emitter junction causes the
through the B/emitter junction of the power transistors entire power transistor to turn on. Now when T327 is
T1P and T2P, through the pump armature/series field to on, T324, T1P (entire) transistor), and T2P (entire
BAT-. Since T1P and T2P are NPN transistors the transistor) are on.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46

R331

R332
R330 34
D321

P2-12

T337
B B
T1P T2P T332 P3-3

P8-1
R327

T331

B0 B0 100 P2-13

R340 R339
T R341

T341 1

P4-7
P4-2
R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1525

152
 SENB8604-02

When the power transistors T1P and T2P turn on, cur- (Wire #79) is low, the power transistors T1P and T2P
rent flows from BAT+ through the power transistors are on. The logics controls this ‘loW’ time on P2-7 to
T1P and T2P, through the pump armature/series field to control the pump during hydraulic functions.
BAT-. This causes the pump to turn. So when P2-7

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46

R331

R332
R330 34
D321
P2-12

T337
B B

T332
T1P T2P P3-3

P8-1
R327

T331
B0 B0 100 P2-13

R340 R339
T R341

T341 1

P4-7

P4-2
R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21
71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1526

153
SENB8604-02

As shown in the chart under Lift Control Circuit, lift results in faster hydraulic operation. Just as the pump
speeds 0-8 keep the shunt field on at 100%. For speed armature/shunt field needs a flyback diode, the shunt
9 the shunt field is pulsed at 50%, and for speed 10 field also needs a path for the current to flow when
the shunt field is turned off. Reducing the shunt field in T351 turns off. D351 serves this function. When T351 is
the pump motor serves the same function as turning turned OFF, all the current flowing in the shunt field
off the shunt field in the drive motor. It changes the goes through E2, through D351, through E1, and back
motor characteristics so that it will spin faster. This to the shunt field.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332
R330 34
D321

P2-12
B B T337
T331

T332

T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13
R340 R339
T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1527

154
 SENB8604-02

Pump Contactor Operation

If lift speed 8, 9, or 10 is set for Option 2 (LIFT1 Speed) current to flow out of P3-17, through the pump contac-
or Option 3 (LIFT2 Speed), and it is necessary to pro- tor coil, through P3-10 to BAT-. While the pump con-
vide one of these speeds because the lift lever has tactor is pulling in the pump, transistors T1P and T2P
been pulled back, then the lift contactor will be used to are driven at 99% to reduce the arc when the contact
provide 100% voltage to the pump armature/series tips touch. After this the transistors are turned off. The
field. The logic activates the pump contactor by allowing pump armature/series field is now connected directly to
the battery.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332
R330 34
D321

P2-12
B B T337
T331

T332

T2P P3-3
T1P

P8-1
R327

B0 B0 100 P2-13
R340 R339

T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1528

155
SENB8604-02

Tilt And Auxiliary Control Tilt

Aux1
The Tilt, Aux1, and Aux2 hydraulic levers each have Aux2
their own microswitch. This allows the speed for Lift1, Lift 2
each function to be set separately using Setup
Options 4, 5, and 6. The same control of pump This means that if you pull back on Tilt and Aux2, the
motor that was explained earlier for the lift lever also speed associated with Tilt will be used.
applies to these three levers.To handle the situation
when more than one lever is pulled, the following
priority is given to the levers

3
3
LIGHTS FUSE 15A
34
P12-13
KEY FUSE 10A 3 HORN BUTTON
P12-11 P12-12 3 P5-3 P46-2 4 P46-1
R319 R320 KEY SWITCH
P3-18 P5-4 4

P3-4 P5-12 12 P6-4 P6-2 4

DISPLAY
46

34 P3-5 P5-16 16 P6-3 P6-1 1

P2-12 LIFT LIMIT SW
P3-3 SEAT OPERATED BRAKE SW
P1-14 127 P5-21 P60-C P60-A
100 1 +
P2-13
SEAT SWITCH 1
P1-13 P5-7 7 1 HORN
2
PUMP MOTOR THERMOSTAT -
P3-2 77 P5-25 1

P3-1 76 P5-24 1
DRIVE MOTOR THERMOSTAT SERVICE BRAKE SWITCH 3
P1-12 P5-23 113 P40-C P40-B 1

P1-11 P5-19 91 1
PARK BRAKE SW BRAKE FLUID SWITCH
P2-20 P5-22 106 P33-2 P33-1

FWD
P1-10 P5-14 14 P7-B 4
DIR SW P7-A 1
34 REV
P1-9 P5-15 15 P7-C
39 P3-17
LINE COIL
XY 26 P3-9 FWD
P61-2
LIFT COIL P61-1 1
X Y 30 P3-10 FOOT DIR SW
REV
BYPASS COIL P38-8 P61-3
LOGICS

XY 35 P3-11
FWD COIL
P1-1 P5-13 13 P13-5 1
XY 20 P3-12
REV COIL LIFT 1 SW
XY 19 P3-13 P1-2 P5-27 81 P13-6 1 4
REGEN COIL LIFT 2 SW
XY 75 P3-14
3 P1-3 P5-34 89 P13-2 1 P32-3 1

38 P3-16 TILT SW
P32-4 3
LINE FUSE P1-4 P5-33 88 P13-3 1
2 TO 3 TON AUX 1 SW 4
36/48 VOLT
675 AMP P1-5 P5-32 87 P13-4 1 P13-1
600 AMP
1TON AUX 2 SW
P1-6 P5-26 78 P24-2 P24-1 1 1
LINE TWISTED PAIR TWISTED PAIR
CTR PRESSURE SWITCH
P1-19 116 P5-31 P52-2
SPEED
SENSOR
P1-18 115 P5-30 P52-1 SWITCH 1 1 4 1
BATTERY
36/48 VOLT P1-15 8 P5-8 P9-C P9-A
OR P9-B
72/80 VOLT ACCEL
CONTROL
P3-21

P1-21
P3-20
P2-21

P5-36

P5-37
P5-2

P5-1

2EC1513

156
 SENB8604-02

Additional Lift System Information:

Two additional systems exist on the EP16 family The shunt is also used to current limit the pump tran-
system that are new to MicroCommand II. The first sys- sistors. Just as the drive transistors are current limited
tem is the pump shunt. This shunt is a precision, very to help protect them, so are the pump transistors. This
low value resistor that measures the current flowing in current limit will not be reached during normal opera-
the pump. The logics uses this information for various tion, but during a pump failure when the pump locks
reasons: Because of the current limitation of the 15,000 up, the transistors are protected from overcurrent.
Hz steering system (-150A), the system must not be
Finally, the shunt is used to prevent a stalled pump
overloaded. During steering idle or steering boost-up,
motor from blowing the main fuse when the pump
the 15,000 Hz system is used, but if the any hydraulic
bypass contactor i-s pulled in. Again, if the pump locks
lever is activated (Lift, Tilt, Aux1, or Aux2) or the current
up and the pump bypass contactor is pulled in, the
in the pump rises above an acceptable limit, the logics
logics will sense the high stalled motor current and
will automatically switch to 187.5 Hz pulsing. The
shut down the truck before the fuse blows.
hydraulic levers are monitored by the microswitches
attached to each spool. The current is monitored with
the pump shunt.

157
SENB8604-02

Pump Power Transistor

Turn-Off Circuit
The second system is the pump power transistor turn- off; and P2-9 will be off when either P2-7 or P2-8 are
off circuit. This circuit helps to turn off the main power on. Because these signals change rapidly, this cannot
transistors T1P and T2P as quickly as possible. This be seen on a voltmeter, but must be viewed with an
helps the 15,000 Hz steering system work more con- oscilloscope. When P2-9 is low, current flows from the
sistently. The turn-off circuit is controlled by the logics BO terminal of T1P and T2P, through the emitter/base
control output P2-9 (Wire #118). When P2-9 is low, the junction of T341, through R342 and R343 to P2-9.
turn-off circuit is active; and when P2-9 is high, the Because T341 is a PNP transistor, the flow of current
turn-off circuit is inactive. Because P2-9 controls the through the emitter/base junction of T341 turns it on.
turn-off circuit, it will be on when P2-7 and P2-8 are So when P2-9 is low, T341 is on.

P4-5

C332
T327 R322
R321

C322
Z324

R328

R338
Z334

THERMOSTAT
P8-2
Z323
T324

CONTROL
R329 46
R331

R332

R330 34
D321

P2-12
T337

B B
T332

T1P T2P P3-3

P8-1
R327

T331

B0 B0 100 P2-13
R340 R339

T R341

T341 1

P4-7
P4-2

R343 R342
45 1
P4-1
P4-4

PUMP
CTR 117 117 P2-8
118 118 P2-9
P12-3 79 79 P2-7
DRIVE 45 P2-10
SHUNT FIELD 83 P5-29 83 P1-8
FUSE 15 AMP 1
P12-1 68
83
PUMP
P12-2

SHUNT FIELD
FUSE 15 AMP
69 39 P3-17
LINE FUSE LINE COIL
P32-5

DU1

LOGICS
2 TO 3 TON XY 26 P3-9
36/48 VOLT LIFT COIL
675 AMP
600 AMP
X Y 30 P3-10
1 TON 109 BYPASS COIL
E1 PA1 DRIVE XY 35 P3-11
(F1) FWD COIL
LINE POWER
CTR ARM 110 CIRCUIT XY 20 P3-12
REV COIL
XY 19 P3-13
REGEN COIL
E2 (PS2)
(F2) XY 75 P3-14
BATTERY PD2
36/48 VOLT 1 HEAD
D4P

OR PUMP CAP 38 P3-16

72/80 VOLT MOTOR
P32-2
D351

P12-6

71 119
P2-18
SHUNT P2-19
T351

P2-4
29
C351
Z351

TWISTED 119
R351

P2-3

PAIR 29
72
P3-21
P3-20
P2-21
P1-21

71
72
P12-10
P12-8

119 119
29 29
71 71
72 72

2EC1530

158
 SENB8604-02

When T341 turns on, current flows from the B0 terminal quickly, and at 15,000 Hz pulsing this would result in
of T1P and T2P, through T341 to the emitter of T1P and the pump running faster than necessary. Although this
T2P. This flow of current is a good way to quickly turn does affect the steering, it means the pump transistors
off the pump power transistors by removing excess are on more than necessary, which results in lower sys-
base charge from the second stage transistor. Without tem efficiency.
this circuit the pump transistors would not turn off

2EC1531

159
SENB8604-02

Electrical Testing If pump circuit failed:

2. Check D4P for a failure.
Testing Transistors 3. Check T1P and T2P for a failure.
Use the following chart to test transistors. If any
measurements are incorrect, replace the transistor. 4. Check pump driver board for a failure.

NOTE: If a transistor is found to be failed and it is 5. Check continuity from T1P, T2P emitter bus bar
part of a pump or drive system pair, replace both (wire #45) to logics P2-10.
transistors of the pair. 6. Check continuity of pump shunt wires (wires #29
and #119).
TRANSISTOR SPECIFICATIONS
1 2
MULTIMETER (+) TEST (-) TEST 927566 974222
SETTING LEAD LEAD RESULTS RESULTS
Resistance Emitter Base 45 to 135 Ω 60 to 180 Ω 3
Diode Base Collector .3 to.9V .3 to.9V
Diode Collector Base OL OL
Diode Emitter Collector .3 to.9V .3 to.9V
Diode Collector Emitter OL OL 3 4

NOTICE: Damage to the control panel could result. C30706P2

927566 and 974222 Transistor
To prevent further damage before a power transistor (1)Emitter (2)Base (3)Collector (4)B0
is replaced, complete the check list that follows.
1. Check head capacitor for a failure.
If drive circuit failed:
2. Check D4D for a failure.
3. Check D5D for a failure.
4. Check D6D for a failure.
5. Check T1D and T2D for a failure.
6. Check drive driver board for a failure.
7. Check continuity from T1D, T2D emitter bus bar
(wire #37) to logics P2-6.
8. Check for continuity of drive current sensor wires
(wires #2, #42, #85).

160
 SENB8604-02

Transistor Replacement 3. Remove the transistor mounting bolts (3).

(T1P, T2P, T1D and T2D)

! WARNING
Battery voltage and high amperage are present.
Injury to personnel is possible. Disconnect the bat-
tery and discharge the head capacitors (HEAD CAP)
before any contact is made with the control panel.
T1P is described in the procedure that follows. All C63562P1: Transistor Removal (Typical)
transistors are replaced in the same way. (4) Contact Surface

1. Disconnect the battery discharge the head 4. Contact surface (4) of transistor (2) is coated with
capacitors, and remove the logics board. 5P8937 Thermal Joint Compound. Carefully
remove the transistor (2).
2 2 5. To replace the transistor, wipe the contact
surface (4) and the heatsink clean. Put a small
1 amount of 5P8937 Thermal Joint Compound on
contact surface (4). Coat heatsink and transistor
so that compound covers only contact area.
6. Install transistor (2) with mounting bolts (3).
Tighten bolts (3) to a torque of 4 to 6 N•m (35 to
53 lb in.).
7. Reinstall driver boards (1).

3 2

Location of Components
(1)Driver Board (2)Transistor (3)Mounting Bolts

2. Remove drive and pump driver boards (1).

161
SENB8604-02

Resistor R312

! WARNING ! WARNING
Battery voltage and high amperage are present.
Injury to personnel is possible. Disconnect the bat-
Resistor R312
tery and discharge the head capacitors (HEAD CAP) Battery voltage and high amperage are present.
before any contact is made with the control panel. Injury to personnel is possible. Disconnect the bat-
tery and discharge the head capacitors (HEAD CAP)
NOTE: Look for visual beaks or cracks on resistors.
before any contact is made with the control panel.
1. Disconnect the battery, discharge the head
capacitor, and remove the logics board. NOTICE: Damage to the thermal switch will occur.
Do not heat the thermal switch over an open flame.

1 Control Panel
NOTE: If the thermal switch is removed from the
heatsink, it can be tested in an oven. Switch (1) will
open circuit if the temperature is 81°-89°C (178°-

Location of Components: (1) R312

2. Disconnect wire #32 from resistor R312 (1). 192°F) and close (short circuit) at 69°-77°C (156°-171°F).
3. Set the multimeter to the 200 ohm range. Refer to the topic “Run-Time Diagnostics”, Overtem-
Connect the multimeter leads to the terminals on perature Indicator ON, in the troubleshooting section.
resistor R312 (1) to check the resistance. 97C54-11300
Location of Components: (1) Thermal switch
4. The measurement from the resistor must be 34 to
38 ohms (36/48V trucks) or 71 to 79 ohms Pump and Drive Motor
(72/80V trucks). NOTE: If the pump or drive thermal switch is
5. If the measurement is not correct, the resistor removed from the motor, it can be tested in an oven.
must be replaced. Switches 3 and 4 will open circuit if the temperature
is 144°-156°C (291°-312°F) and close (short circuit) at
124°-136°C (255°-276°F).
Refer to the related problems under “Run-Time
Diagnostics”, Overtemperature Indicator ON, in the
Troubleshooting Section.

Location of Components: (1) Drive Motor (2) Pump Motor

(3) Pump Motor Thermal Switch (4) Drive Motor Thermal Switch

162
 SENB8604-02

Electrical System Accelerator Control Linkage

Adjustments
Method A (Mechanical)
1. Disconnect the battery.
2. Fully depress the accelerator pedal (1) until pedal
is stopped on bolt (3). Adjust bolt so that groove
(4) on accelerator control shaft (2) is even with
face (5) of accelerator control (6). The groove
should not reach the shaft wiper.
3. Release accelerator pedal (1).
Method B (Electrical)
1. Place the truck in the “Self” Diagnostic mode and
proceed to test 5.
2. Cycle the RUN/DIAG/SETUP switch so that the
accelerator speed is flashed on the display. Accelerator Control Linkage: (1) Accelerator Pedal
(2) Accelerator Control Shaft (3) Bolt (4) Groove (5) Face
3. Depress the accelerator pedal until the floor plate (6) Accelerator Control
bolts stops the pedal motion.
4. Adjust the floor plate bolt until a “14” is flashed
on the display. If the speed flashed is less team
“14”, adjust the bolt to allow more pedal travel. If
the speed flashed is more than “14”, adjust the
bolt to allow less pedal travel.
5. Adjust the floor plate bolt just enough to get the
display to change from a flashing “14” to a
flashing “15”. Ensure that the groove on the
accelerator control shaft does not reach the shaft
wiper when the accelerator is fully depressed.

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SENB8604-02

Parking Brake Switch Lift, Tilt, and Auxiliary Switches

Each function has its own independent microswitch for
! WARNING activating the hydraulic pump motor. Refer to the topic
“Programmable Features” in the System Operation
The lift truck can move suddenly. Injury to section of this manual for information on adjusting lift
personnel or damage to the lift truck is possible. tilt, and auxiliary speeds.
Safely lift the drive wheels off the floor. Put blocks
of wood under the frame so that both drive wheels
are free to turn.
1
1. Close the seat switch and turn the key ON. 4
2. Release the parking brake and put the truck in
forward.
3. Depress the accelerator. With the tires in rotation, 2
3
apply the parking brake.
4. Tire rotation should slow and/or stop and the
parking brake action light should turn ON.
5. If the parking brake action light did not turn ON,
check the parking brake switch and wiring to the
logics. Refer to problem 40, “Park Brake Circuit
Defect” in the Troubleshooting Section.

Location of Components: (1) Lift 1 Switch (2)Lift 2 Switch

(3) Tilt Switch (4) Aux 1 Switch

Location of Components: (1) Switch

164
 SENB8604-02

Rapid Tune-Up Procedure

The rapid tune-up procedure establishes a starting
! WARNING
point for logic card adjustments. The following proce- The lift truck can move suddenly. Injury to
dure allows the truck to be operated for test purposes personnel or damage to the lift truck is possible.
without damage to the truck or its components. Safely lift the drive wheels off the floor. Put blocks
of wood under the frame so that both drive wheels
Always verify that the jumper on the logic board is in its
are free to turn.
proper position for the voltage of the lift truck being
tuned. NOTE: All programmable features should be set to
their default values before making any adjustments.
J1 = 36V J2 = 48V J3 = 72V J4 = 80V
See the topic “Activating Default Settings” in the
Service exchange logic boards do not need a rapid Systems Operation section of this manual.
tune-up procedure. These boards are pre-adjusted 1. Turn current limit potentiometer P1 fully
from the factory and their programmable features are counterclockwise, then eight turns clockwise.
set to the default values. However, Option #30 must be
programmed to the correct truck type and size. The 2. Turn electrical braking potentiometer P3 fully
current limit, electrical braking, and BDI should be counterclockwise, then eight turns clockwise.
checked and adjusted by certified technicians. 3. Make the final adjustments, as specified in each
of the Testing and Adjusting Procedures, before
putting the truck back into service. Perform these
procedures in the following order.
1. Battery Discharge Indicator (BDI)-P5
2. Current Limit-P1
3. Electrical Braking-P3

Logics Board

165
SENB8604-02

Current Limit Test and Adjustment 4. For ease in reading the equipment, a 6V7070
Digital Multimeter may be set to the 2VDC range
and connected to the 8T0900 Digital Ammeter
! WARNING using a 6V6014 Cable. For more information,
refer to Special Instruction SEHS8030.
The lift truck can move suddenly. Injury to
personnel or damage to the lift truck is possible. 5. Get on the truck. Turn the key switch on. Clear
Safely lift the drive wheels off the floor. Put blocks any SRO conditions if necessary. Release the
of wood under the frame so that both drive wheels park brake.
are free to turn. 6. Place the direction lever in either forward or
NOTICE: Damage can be caused to the control panel. reverse. Depress the service brake. The drive
Do not switch the direction lever from one direction to wheels must NOT turn during this procedure.
the other (plug the truck) when the drive wheels are 7. Depress the accelerator fully. Measure the
off the ground and in rotation at full speed. current in A1. Values should be as follows:
NOTE: Current limit is preset and sealed at the factory
and should only be adjusted by certified mechanics MODEL CURRENT LIMIT (AMPS)
with calibrated equipment.
36/48V 72/80V
2EC15 / 18 400 ± 5% 425 ± 5%
2EC20 / 25 / 25E 525 ± 5% 425 ± 5%

1 2EC30 525 ± 5% 450 ± 5%

NOTICE: Do not stall the drive motor for more
than three seconds. Damage to the motor will result.
Between stalls allow the drive wheels to turn with the
tires off the floor to cool the motor. If the motor remains
stalled for more than three seconds, the line contactor
will open and “20” will appear in the display.
8. If the current value is not acceptable, adjust
(1) 8T0900 Digital Ammeter
potentiometer P1 until the value is correct. Turn
the adjustment screw clockwise to increase
1. Begin this procedure with the key switch OFF current. Turn the adjustment screw counterclock-
and the park brake applied. Put blocks of wood wise to decrease current.
under the frame so that both drive wheels are
free to turn. Between adjustments, allow the motor to turn.
This will prevent sitting on one spot on the
2. Enter Setup Mode and set the following Options: commutator, which could cause damage to the
Option 13 = 13 motor.
Option 20 = 0
Option 22 = 13 9. After the current value is correct, turn off the
truck. Use setup modes to return Options 13, 20,
3. Connect 8T0900 Digital Ammeter around the and 22 to their original values.
loop in cable A1 to check drive motor current
limit. Current Limit is now set.
NOTE: The arrow on the ammeter points in the
direction of current flow for a positive indication.

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 SENB8604-02

Electric Braking Current

Test and Adjustment
1. Make sure the current limit is adjusted to
specification before adjusting electric braking
current. If current limit is changed after setting 1
plugging current, plugging current will change.
2. Connect 8T0900 Digital Ammeter (1) around
cable A1 to check plugging motor current. Check
the jaws of the meter to make sure they are fully
closed.
NOTE: The arrow on the ammeter points in the
direction of current flow for a positive indication.)
(1) 8T0900 Digital Ammeter
3. For ease in reading current, a 6V7070 Digital
Multimeter may be set to the 2V DC range and
connected to the 8T0900 Digital Ammeter using
a 6V6014 cable. Refer to Special Instruction
SEHS8030 for more information.
4. Move the lift truck FORWARD at full speed.
Keep the accelerator pedal fully depressed and
change the direction control to REVERSE.
5. The current measured during electrical braking
(plugging) must be 300 amps ±-5%.
NOTE: Though the plugging distance is an
application adjustment, plugging current should
not exceed 315 amps. If the recommended cur
rent produces a short stopping distance, the
distance may be lengthened by turning poten-
tiometer P2 counterclockwise to reduce plugging
current.

167
SENB8604-02

Logic Board Layout 1. Disconnect the battery and discharge the head
capacitor. Remove logics cover and verify the
DIAG/RUN switch is in the RUN position.
! WARNING
2. Make sure BDI jumper is positioned properly:
IMPORTANT!
Since many battery manufacturers have different J1 for 36V J2 for 48V J3 for 72V J4 for 80V
types of batteries available, the Battery Discharge
3. Set the multimeter to measure battery voltage.
Indicator (BDI) should be adjusted to meet the bat-
Connect the multimeter positive lead to logic
tery manufacturer’s specifications for a discharged
terminal P3-18. Connect the multimeter negative
state.
lead to control panel battery negative (negative
The BDI Information provided is to be used FOR heatsink).
REFERENCE ONLY. Please consult the battery man-
4. Put the direction lever in Neutral and connect
ufacturer for the correct discharge state for your
the battery.
particular batteries.
5. Close the seat switch and turn the key ON. The
Before adjusting BDI, remove battery surface
measurement should be battery voltage. The
charge by operating hydraulic system against tilt
display must show the correct number for the
pressure relief for five seconds.
voltage measured as shown in the charts that
follow:

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 SENB8604-02

Battery Discharge Indicator FRENCH BATTERY DISCHARGE INDICATOR

Adjustment Charts ADJUSTMENT CHART
(FOR FRENCH TUBULAR TYPE BATTERIES) — 36 VOLT/48 VOLT
NORMAL BATTERY DISCHARGE INDICATOR
BDI # 36 VOLT BATTERY 48 VOLT BATTERY
BDI# 36V BATTERY 48V BATTERY
0 0 - 36.0 0 - 48.0
0 0 - 36.0 0 - 48.0
1 36.0 - 36.2 48.0 - 48.2
1 36.0 - 36.2 48.0 - 48.5
2 36.2 - 36.5 48.2 - 48.7
2 36.2 - 36.7 48.5 - 48.9
3 36.5 - 36.7 48.7 - 48.9
3 36.7 - 36.9 48.9 - 49.4
4 36.7 - 36.9 48.9 - 49.4
4 36.9 - 37.1 49.4 - 49.6
5 36.9 - 37.4 49.4 - 49.6
5 37.1 - 37.6 49.6 - 50.1
6 37.4 - 37.6 49.6 - 50.1
6 37.6 - 37.9 50.1 - 50.6
7 37.6 - 37.9 50.1 - 50.3
7 37.9 - 38.1 50.6 - 51.0
8 37.9 - 38.1 50.3 - 50.8
8 38.1 - 38.6 51.0 - 51.3
9 38.1 - 38.3 50.8 - 51.0
9 38.6 - 38.8 51.3 - 51.8
10 38.3 - 51.0
10 38.8 - 39.1 51.8 - 52.1 1= Display is Incrementing
1= Display is Incrementing

FRENCH BATTERY DISCHARGE INDICATOR

NORMAL BATTERY DISCHARGE INDICATION ADJUSTMENT CHART
ADJUSTMENT CHART— 72 VOLT / 80VOLT (FOR FRENCH TUBULAR TYPE BATTERIES) — 72 VOLT/80 VOLT

BDI# 72V BATTERY 80V BATTERY BDI # 72 VOLT BATTERY 80 VOLT BATTERY
0 0 - 72.0 0 - 80.0 0 0 - 72.0 0 - 80.0
1 72.0 - 72.6 80.0 - 80.9 1 72.0 - 72.6 80.0 - 80.6
2 72.6 - 73.6 80.9 - 81.9 2 72.6 - 73.2 80.6 - 81.2
3 73.6 - 74.3 81.9 - 82.6 3 73.2 - 73.8 81.2 - 81.8
4 74.3 - 75.0 82.6 - 83.5 4 73.8 - 74.1 81.8 - 82.3
5 75.0 - 76.0 83.5 - 84.2 5 74.1 - 74.7 82.3 - 82.9
6 76.0 - 76.7 84.2 - 85.2 6 74.7 - 75.3 82.9 - 83.5
7 76.7 - 77.4 85.2 - 86.1 7 75.3 - 75.7 83.5 - 84.1
8 77.4 - 78.3 86.1 - 86.8 8 75.7 - 76.3 84.1 - 84.7
9 78.3 - 79.0 86.8 - 87.7 9 76.3 - 76.9 84.7 - 85.3
10 79.0 - 87.7 - 10 76.9 - 85.3 -
1= Display is Incrementing 1= Display is Incrementing

EXAMPLE: If the measurement is 36.8 volts for a

36 volt battery, the display should be at 6.

169
SENB8604-02

6. If the display is not correct, turn the key OFF and If the display shows a “0”, this indicates that the
make an adjustment to potentiometer 5. Adjust battery is discharged. The display will not show any
potentiometer P5 a small amount. Turn it clock battery charge level unless the battery voltage is above
wise to increase and counterclockwise to a level “6”. See the topic “Programmable Options:
decrease the display number. Repeat step 5. Option 17” in the Systems Operation section.
Turn the key to OFF between each adjustment.
There are two battery discharge indicator ranges that
7. If the voltage was 36.8, the potentiometer should can be selected. See Programmable Option 25.
be tuned to find the transition point between 7
and 6 on the display. This will assure that the
logics is calibrated at high 6.
NOTE: Approximately 1/4 turn of potentiometer P5
changes the display one number.
When the BDI of the lift truck suggests that the battery
is discharged 80%, the specific gravity of the battery
should be checked also. The specific gravity should
then be compared to the battery manufacturer’s rec-
ommended specific gravity for 80% discharge. If the
specific gravity is too low, P5 should be turned coun-
terclockwise to reduce the BDI number. If the specific
gravity is too high, P5 should be turned clockwise to
increase the BDI number. Logics Board

170
 SENB8604-02

Harness Wiring Circuit Guide The following chart can be used when troubleshooting
The main lift truck electrical harness uses multicolored as a guide to the circuit function. This guide applies only
wires connected to different components on the truck. to the main harness wiring, not the component wiring.

EP MicroCommand II WIRE CONNECTIONS

WIRE # COLOR CONNECTOR PIN # WIRE TERMINATIONS
1A BROWN P13-1, P5-1 HYD. SW., LOGICS, BATTERY NEG
1B BLUE P7,P5-2,T18,P24-1, P9-A, P6-1, DIR. CTRL,LOGICS,SEAT SW.,PRESS.SW,ACCEL.,DISPLAY,SEAT BRAKE
P60-A SW,FOOT DIR. CTRL,BATT NEG
1C YELLOW P5-36,P33,P40-A,T17,T9,T7 LOGICS,BRAKE FLUID,FOOT BRAKE SW,PARK BRAKE SW,BATTERY NEG
1D BLACK P39-7,P32-3,P38-1,P39-8 DC/DC CONV, SHUNT FIELD CONN., REAR OPTION, BATTERY NEG
1E RED P5-37,T14,T13 LOGICS,HORN,HORN FILTER,BATTERY NEG
3 ORANGE P5-3,P46-2 LOGICS,CONSOLE GENERAL, BATTERY POS
3A WHITE/ T1, WIRE 3 HORN SW., BATTERY POS.
ORANGE
3B ORANGE P39-1, P32-4 DC/DC CONV., SHUNT FIELD CONN.,BATTERY POS.
4 WHITE P5-4, P46-1, P9-B,39-6, P38-2, P6-2, P38-3 LOGICS,CONSOLE GENERAL, ACCEL,DC/DC CONV, REAR OPTIONS, DISPLAY
7 BLACK P5-7,T19,P60-C LOGICS,SEAT SWITCH,SEAT BRAKE SWITCH
8 YELLOW P5-8, P9-C LOGICS, ACCEL
12 BROWN P5-12, P6-4 LOGICS DISPLAY
13 GRAY P5-13, P13-5 LOGICS, HYD. SW.
14 WHITE/ P5-14, P7, P61-2 LOGICS, DIR. CONTROL, FOOT DIR. CTRL.
BROWN
15 WHITE/ P5-15, P7, P38-8, P61-3 LOGICS, DIR. CTRL.
GREEN
16 BROWN P5-16, P6-3 LOGICS, DISPLAY
24 GREEN T2, T15, T12 HORN, HORN SW., HORN FILTER
53 BLACK P39-4, P41-1,P42-1,P38-5,P39-5 DC/DC CONV.,HEAD LAMP RIGHT, HEAD LAMP LEFT, REAR OPTIONS
55 YELLOW/ P48,P38-6 LIGHT SW., REAR OPTIONS
BLACK
56 YELLOW P48,P41-2,P42-2 LIGHT SW., HEAD LAMP RIGHT, HEAD LAMP LEFT
66 GREEN P39-2,P46-3,P46-7,P39-3 DC/DC CONV.,CONSOLE GENERAL
68 RED P32-6,T24 SHUNT FIELD CONN.,TRACTION MOTOR SHUNT FIELD
69 GREEN P32-5,T22 SHUNT FIELD CONN., PUMP MOTOR SHUNT FIELD
71 WHITE P32-2, T21 SHUNT FIELD CONN., PUMP MOTOR SHUNT FIELD
76 BLACK P5-24,T8 LOGICS,TRACTION MOTOR THERMAL SW.
77 BLUE P5-25,T6 LOGICS,PUMP MOTOR THERMAL SW.
78 BLUE P5-26,P24-2 LOGICS,PRESSURE SW.
81 BLUE P5-27,P13-6 LOGICS,HYDRAULIC SW.
82 WHITE P5-28,DU2-2 LOGICS, DIODE BLOCK 2
83 BLUE P5-29,DU1-2 LOGICS, DIODE BLOCK 1
87 BLUE P5-32, P13-4 LOGICS, HYDRAULIC SW.
88 YELLOW P5-33,P13-3 LOGICS, HYDRAULIC SW.
89 YELLOW P5-34,P13-2 LOGICS, HYDRAULIC SW.
91 BLACK P5-19,T16 LOGICS, PARK BRAKE SW.
92 WHITE P32-1,T23 SHUNT FIELD CONN.,TRACTION MOTOR SHUNT FIELD
106 GREEN P5-22,P33 LOGICS, BRAKE FLUID SW.
107 YELLOW DU2-1,T11 DIODE BLOCK 2, TRACTION MOTOR BWI
108 YELLOW DU2-3,T10 DIODE BLOCK 2,TRACTION MOTOR BWI
109 GREEN DU1-1,T4 DIODE BLOCK 1,PUMP MOTOR BWI
110 YELLOW DU1-3,T5 DIODE BLOCK 1,PUMP MOTOR BWI
113 RED P5-23, P40-C LOGICS, FOOT BRAKE SW
115 RED P5-30, P52-1 LOGICS, SPEED SENSOR
116 GREEN P5-31,P52-2 LOGICS, SPEED SENSOR
122 YELLOW P46-8,P48 CONSOLE GENERAL, LIGHT SW.

171
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Date:

(Please Print)
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Address: P.O. Box:
City: State:
Zip Code: Country:

The following discrepancy or omission has been discovered in:

o Operation & Maintenance Manual o Option Bulletin

o Part List/Manual o Special Instructions

o Service Manual o Service Data Manual

o Electronic Manual o Other

Publication # Engine Model #

Truck model # Issue date #

Truck serial # Page #

(Please Print)
Explanation of discrepancy or omission:

(Please fax or mail completed form to):

Mitsubishi Caterpillar Forklift America Inc. Mitsubishi Caterpillar Forklift Europe B.V.
Attn: Technical Publications Attn: Service Engineering
2121 W. Sam Houston Parkway N. P.O Box 30171
Houston, Texas 77043-2305 1303 AC, Almere, The Netherlands
Fax: 713-365-1616 Fax: 31-36-5494-695

Mitsubishi Caterpillar Forklift Asia Pte. Ltd.

RCB No. 199203169H
Attn: Service Engineering
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Republic of Singapore
Fax: 65-6861-9277
Cat Lift Trucks Service Manual 2EC15, 2EC20, 2EC25, 2EC25E, 2EC30 Lift Trucks SENB8604-02
 ®
Lift
Trucks

Mitsubishi Caterpillar Forklift America Inc.

2121 W. Sam Houston Parkway N.
Houston, TX 77043-2305

Copyright © 2005 by MCFA. All Rights Reserved.

SENB8604-02 CATERPILLAR and CAT are registered trademarks of Caterpillar Inc. Printed in the U.S.A.