Service Training

SERV2742
August 2003

TEXT REFERENCE

PART OF TECHNICAL INSTRUCTION MODULE SERV2742

980G SERIES II WHEEL LOADER

3406E ENGINE CONTROLS
SERV2742 -2- Table of Contents
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TABLE OF CONTENTS

INTRODUCTION..........................................................................................................................3
Engine Orientation ...................................................................................................................4
Major Components ...................................................................................................................5
Lab A: Electronic Tool Operations .........................................................................................8

FUEL INJECTION SYSTEM........................................................................................................9

Lab B: Fuel Injection System Component Identification .....................................................17

ENGINE ELECTRICAL/ELECTRONIC COMPONENTS .......................................................18

Engine Block Diagram ...........................................................................................................18
Engine ECM, Senders, and Sensors .......................................................................................19
Electronic Unit Injector ..........................................................................................................29
Injector Testing Review .........................................................................................................30
Lab C: Fuel Injection System Component Removal, Installation, Testing and Adjusting ...32

MACHINE ELECTRICAL/ELECTRONIC SYSTEMS ............................................................33

Machine Block Diagram ........................................................................................................33
Ether Injection System ..........................................................................................................35
CAT Data Link .......................................................................................................................37
Demand Fan System ..............................................................................................................40
Ground Level Shutdown Switch ............................................................................................44
Engine Derates and Automatic Power Adjustments .............................................................45
3406 Engine Events ...............................................................................................................47
Major Component Review .....................................................................................................48
Lab D: Electric/Electronic Component Identification ..........................................................49
Lab E: Electric/Electronic Component Removal, Installation, Testing and Adjusting ........49
Lab F: General System Diagnostics .....................................................................................49
Visual List ..............................................................................................................................50
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980G SERIES II WHEEL LOADER

3406E ENGINE CONTROLS

© 2003 Caterpillar Inc.

INTRODUCTION

Objective 1 This presentation describes the 3406E Electronic Unit Injection (EUI)
Visuals 2 - 5, 7 - 14, Fuel System used in the 980G Series II Wheel Loader.
16 - 26, and 29 - 40

The presentation will review the Electronic Unit Injection (EUI) fuel
system’s mechanical and electrical/electronic components with particular
attention to those components specific to the 980G Series II Wheel
Loader.

Each portion of the presentation is followed by a lab exercise to reinforce

the location and function of each major component. These lab exercises
are followed by disassembly, assembly, and testing and adjusting
activities.

INSTRUCTOR NOTE: If desired, Lab Exercise A can be performed

prior to the start of the class and can become a prerequisite as
required.
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• Engine orientation in Engine Orientation

machine
The 980G Series II Wheel Loader uses the 3406E EUI diesel engine. The
14.6 liter 3406E engine rated at 232 kW (311 HP) replaces the Caterpillar
3406C diesel engine used in the 980G.

• Engine faces the rear The engine is mounted with the front of the engine toward the rear of the
machine. To avoid any possible confusion, when mounted in the
machine, the sides of the engine will be referenced to the machine and not
to the engine. Therefore, the left side of the engine will be referenced
from the right side of the machine. This process will be used even when
the engine is shown removed.

Many of the photos have been shot with the engine removed for clarity.
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Major Components

• Major components The major EUI components or circuits on the 980G Series II include the
following (shown from left to right):

- Speed/Timing
- Speed/Timing Sensor
Sensor
- Throttle Position Sensor
- Throttle Position
Sensor
- Engine Electronic Control Module (ECM)
- Injector
- Engine ECM
- Pressure Sensor
- Injector - Temperature Sender
- Pressure Sensor
The CAT Data Link (not shown) is also a vital part of the EUI fuel
- Temperature Sender
system.
- CAT Data Link
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3
2

• 980G II engine This view of the engine can be seen from the right side of the engine
compartment right compartment. The view shows the following principle components:
side (machine view)

- Fuel Transfer Pump (1)

1. Fuel Transfer
Pump - Primary Fuel Filter (2)
2. Primary Fuel Filter - Secondary Fuel Filter (3)
3. Secondary Fuel
Filter
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4 2

3
5

• Engine compartment From the left side of machine, the following components are located:
left side view

1. Coolant Pump - Coolant Pump (1)

2. Oil Filter - Oil Filter (2)
3. Oil Pressure - Oil Pressure Sensor (3)
Sensor
- Power Train Oil Cooler (4)
4. Power Train Oil
Cooler - Engine Oil Cooler (5)
5. Engine Oil Cooler
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980G SERIES II WHEEL LOADER

3406E ENGINE CONTROLS

Lab A

Electronic Tool Operations

Introduce and perform Lab A: Electronic Tool Operations

Lab A
If Lab Exercise A has not been previously completed as a course
Objective 2
prerequisite, perform Lab A at this time to identify the skill levels of the
participants. This Lab can be a review of the Electronic Technician (ET)
and computer operations, or can be performed before the class if the
students are not experienced. The students must demonstrate proficiency
in the following tasks to complete the labs which follow.
Start up and shut down a PC correctly.
Operate Microsoft Windows 95/98/NT/2000/XP™.
Identify the ET version number.
Install ET and update ET software files.
Update Communications Adapter software.
Connect and operate the ET Service Tool on a training aid or machine.
Navigate through all screens using a mouse and the keyboard.
Read all parameters.
Reconfigure a status screen.
Access flash files and perform flash programming.
Discuss the hardware minimum requirements for the PC with ET as shown
in the Booklet "ET Service Tool Software/Getting Started"
(Form JEBD3003).
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TEMPERATURE
PRIMARY FUEL FILTER/ FUEL SENDER
WATER SEPARATOR TRANSFER PUMP

ENGINE ECM
RELIEF FUEL
PRIMING PUMP
VALVE PRESSURE
FUEL REGULATOR
MANIFOLD VALVE
SECONDARY
FUEL FILTER
(2 MICRON)
FUEL GALLERY
TANK

ELECTRONIC UNIT
INJECTORS

Objective 3 FUEL INJECTION SYSTEM

Visuals 7 - 14
Fuel is drawn from the tank through the Primary Fuel Filter and the
• Trace circuit and priming pump by the gear-type Fuel Transfer Pump. The fuel then flows
review component through the Fuel Manifold. The fuel is then directed through the Engine
functions
Electronic Control Module (ECM) housing fuel gallery for cooling
purposes. Fuel flows from the Engine ECM to the Secondary Fuel Filter.
Next, the fuel enters the gallery located in the cylinder head. Any excess
fuel not injected leaves the cylinder head. The flow then passes through
the Fuel Pressure Regulator Valve, which has a cracking pressure of
415 kPa (60 psi).

• Excess fuel cools From the Fuel Pressure Regulator Valve the fuel passes over a check valve
injectors and then the excess flow returns to the tank. The ratio of fuel between
combustion and fuel returned to the tank is approximately 3:1 (i.e. four
times the volume required for combustion is supplied to the system for
combustion and injector cooling purposes). A fuel temperature sender is
located in the Fuel Manifold (shown above).
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3
4

1. Primary Fuel Filter The Primary Fuel Filter (1) on the left front side of the engine removes
- 10 micron filter debris down to 10 microns in size. This filter serves to protect the Fuel
Transfer Pump from debris and extends the life of the Secondary Fuel
Filter.

- Water separator Fuel is drawn from the tank through the Primary Fuel Filter. The Primary
Fuel Filter contains a water separator which is a vital part of the fuel
system.

Any high pressure fuel system will deteriorate rapidly if water is allowed
to circulate through the system. Water can cause premature wear or
seizure of the injectors due to corrosion and a lack of lubricity. The
normal expected fuel system life will not be achieved if contaminated fuel
is used. Use clean fuel and keep it clean.
2. Fuel Priming Pump

3. Check Valve Fuel from the Primary Fuel Filter flows to the Fuel Priming Pump (2) and
to the Check Valve (3) located in the base for the Primary Fuel Filter.
4. Check Valve
There is also a Check Valve (4) for the Fuel Priming Pump in the base for
the Primary Fuel Filter.
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• Fuel Priming Pump The Fuel Priming Pump is a roller vane pump driven by an electric motor.
The Fuel Priming Pump is used to prime the fuel system for maintenance
purposes such as filling the fuel filters and eliminating air from the fuel
system.
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10

• Fuel Transfer Pump Fuel flows from the Primary Fuel Filter to the Fuel Transfer Pump (1).
(arrow) The Fuel Transfer Pump is located at the rear of the front gear train. The
Fuel Transfer Pump is a gear type pump which delivers fuel at a pressure
of approximately 620 kPa (90 psi) between low idle and full load. This
pressure is controlled by the Fuel Pressure Regulator Valve. The pump is
protected by an internal relief valve which is set at 860 kPa (125 psi).

The Fuel Transfer Pump supplies more fuel than is required for
combustion. With a fuel supply ratio of 3:1, approximately one part is
used for combustion, and three parts are used to cool the injectors. The
excess fuel is then returned to the Fuel Tank.
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11

• Fuel Manifold (arrow) Fuel flows from the Fuel Transfer Pump through the Fuel
Manifold (arrow). Fuel passes through the Fuel Manifold twice. The
temperature of the fuel is measured on the first pass. On the second pass,
the fuel will pass over the Fuel Pressure Regulator Valve.

The Fuel Temperature Sender (not shown) is also located on the Fuel
Manifold. The signal from the Fuel Temperature Sender is used by the
Engine ECM to determine the temperature of the fuel. The Engine will
compensate for changes in power caused by fluctuations in fuel
temperature.

The Engine ECM regulates engine power between 30 - 90°C (86 -194°F).
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12

• Engine ECM (arrow) Fuel from the Fuel Manifold flows to the Advanced Diesel Engine
Management (ADEM) III Engine ECM (arrow). The Engine ECM is
located on the right side of the Engine Compartment. The fuel flowing
through the Engine ECM is used to cool the Engine ECM.
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13

• Secondary Fuel Filter Fuel from the Engine ECM flows through the Secondary Fuel
(arrow) Filter (arrow). The filter removes debris as small as 2 microns. It is
essential that filters with the correct micron rating are installed. The Fuel
Priming Pump must be used to fill the filters to avoid contaminating the
fuel system with unfiltered fuel.

If, for example, an early style 10 micron filter is installed, components

such as the Injector Plunger and the Barrel, which have clearances as
small as 5 microns, will be damaged. Laboratory tests have shown that
when 3 to 8 micron size particles pass between these close tolerance
moving parts, short injector life will result.
Fuel flows from the Secondary Fuel Filter to the Fuel Gallery and to the
EUI Injectors.
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1
3

14

1. Fuel Pressure Return fuel from the EUI Injectors flows through the Fuel Pressure
Regulator Valve Regulator Valve (1) located in the Fuel Manifold (2). The Fuel Manifold
2. Fuel Manifold
is located on the right side of the machine to the rear of the Engine ECM.
The Fuel Pressure Regulator Valve has a cracking pressure between 415
and 450 kPa (60 and 65 psi).
3. Check Valve
The fuel flows through the Check Valve (3) before returning to the Fuel
Tank.
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980G WHEEL LOADER

3406E ENGINE CONTROLS

Lab B

Fuel Injection System

Component Identification

15

Introduce and perform Lab B: Fuel Injection System Component Identification

Lab B
Perform Lab B and identify the following components on the machine
and the engine. Assist the students in explaining the function of each
component.

Injector
Fuel Priming Pump
Primary Fuel Filter
Fuel Transfer Pump
Secondary Fuel Filter
Engine ECM
Fuel Manifold
Fuel Pressure Regulating Valve

Trace the flow from the tank, through the various fuel supply components,
to the return line, and back to the tank.
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3406E ENGINE SYSTEM BLOCK DIAGRAM (980G II)

ENGINE MOUNTED COMPONENTS
6 DRIVERS
INJECTOR
CONNECTOR
3 RETURNS

ELECTRONIC UNIT ADEM III

INJECTORS ECM

CRANKSHAFT SPEED/TIMING SENSOR

TO MACHINE WIRING
CAMSHAFT SPEED/TIMING SENSOR HARNESS

GROUND BOLT
COOLANT TEMPERATURE SENDER

FUEL TEMPERATURE SENDER FUEL PRESSURE SENSOR

INLET AIR TEMPERATURE SENDER

TIMING CALIBRATION
CONNECTOR
ATMOSPHERIC PRESSURE SENSOR

TURBO OUTLET PRESSURE SENSOR OIL PRESSURE SENSOR

16

Objective 4 ENGINE ELECTRICAL/ELECTRONIC COMPONENTS

Visuals 16 - 26 and
29 - 40 Engine Block Diagram

• Engine block diagram This diagram identifies the electronic components mounted on the engine:

Engine ECM, senders, and sensors

Electronic unit injectors
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1 2

17

Engine ECM, Senders, and Sensors

1. ADEM III Engine The principal component in the EUI system, the ADEM III Engine
ECM Electronic Control Module (ECM) (1), is mounted on the right rear of the
engine.

The Engine ECM is the "brain" of the engine. The Engine ECM performs
engine governing, timing, and fuel limiting. It also monitors sensor and
sender outputs and communicates to the Caterpillar Monitoring System
and other machine ECMs through the CAT Data Link.

• Personality Module The Personality Module is used by the Engine ECM to store all the rating
not serviced information for a particular application. The Personality Module cannot
• Flash programming be physically replaced, but must be flash programmed (reprogrammed)
used for updates using a PC. The Engine ECM has no Personality Module Access Panel.

Among the visible components are the Wiring Harness and 70 Pin
Connectors to the Engine ECM.

Notice the fuel lines entering and leaving the Engine ECM. Fuel is used
to dissipate the heat generated by the injector drivers and other
components within the Engine ECM.

2. Timing Calibration Also pictured is the Timing Calibration Connector (2).

Connector
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18

• Speed/Timing The Speed/Timing Sensors are located at the rear of the timing gear
Sensors cover: The Camshaft (arrow) and the Crankshaft (not pictured)
Speed/Timing Sensors are used by the Engine ECM to determine engine
speed and when to inject fuel.

These sensors can substitute for each other. If either fails, the other can
• Sensors are not provide a limited back up. These sensors are not interchangeable, and
interchangeable have mounting brackets which preclude interchangeability.
SERV2742 - 21 -
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19

• Coolant Temperature The engine Coolant Temperature Sender (arrow) is located on the front of
Sender (arrow) the engine, near the coolant temperature regulator. This sender signal is
used by the Engine ECM to control various functions. The following
systems or circuits use the Coolant Temperature Sender output to the
Engine ECM:

• Sender functions - The Caterpillar Monitoring System Coolant Temperature Gauge

and the High Coolant Temperature Warning Alert Indicator LED
on the Caterpillar Monitoring System panel.
(The information is transmitted via the CAT Data Link.)
- The Cat Electronic Technician (ET) status screen shows the
coolant temperature indication.
- Ether Starting Aid
- Variable Speed Fan Control
- High Coolant Temperature Engine Derate
SERV2742 - 22 -
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20

• Fuel Pressure Sensor The Fuel Pressure Sensor (arrow) signals the Engine ECM, which informs
(arrow) the operator if the fuel pressure is too high or too low. The Cat Electronic
Technician (ET) status screen shows the fuel pressure reading.
SERV2742 - 23 -
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21

1. Atmospheric The Atmospheric Pressure Sensor (1) is installed on the cylinder block
Pressure Sensor below the fuel manifold and is vented to the atmosphere within the
engine. This sensor has various functions which are fully described in the
3406E presentation.

- Sensor functions Briefly, the sensor performs the following functions:

- Ambient pressure measurement for automatic altitude

compensation and ET
- ET and Caterpillar Monitoring System panel (gauge) pressure
calculations
- Pressure sensor calibration
2. Inlet Air The Inlet Air Temperature Sender (2) is mounted in the cylinder head (on
Temperature the right side of the machine) and is used by the Engine ECM to perform
Sender
the following functions:

- Air inlet high temperature warning

- Air inlet high temperature engine derate
SERV2742 - 24 -
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• Effects of high inlet High air inlet temperatures can cause very high exhaust temperatures in a
temperature ratio of about three to one. For example, the air inlet temperature can rise
from 40 to 90°C (100 to 200°F). This condition can cause the exhaust
temperature to rise from 500 to 700°C (1000 to 1300°F), resulting in
possible exhaust valve or turbocharger damage.

• Causes of high Various conditions which might cause high exhaust temperature are: low
exhaust temperature fan speed causing high inlet temperature, retarded timing, overload, a
plugged aftercooler (debris), and high ambient temperature conditions in
combination with some of the preceding conditions.
SERV2742 - 25 -
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22

• Oil Pressure Sensor The Oil Pressure Sensor (arrow) is mounted in the oil gallery on the left
(arrow) side of the machine, behind the oil filter. This sensor output is used by
the Engine ECM to provide the following:

- Caterpillar Monitoring System lubrication pressure reading

- ET lubrication pressure reading
- Logged event which can be read by ET
- Warning for low oil pressure
- Engine derate for low oil pressure
SERV2742 - 26 -
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23

• Turbocharger Outlet The Turbocharger Outlet Pressure Sensor (arrow) is mounted in the
Pressure Sensor cylinder head (on the right side of the machine) and is used by the Engine
(arrow)
ECM to control the air/fuel ratio.

This sensor output is used to limit fuel delivery during acceleration when
the turbocharger speed is increasing. The Engine ECM controls the
air/fuel ratio and prevents overfueling before the engine has sufficient air
to burn the fuel.

This sensor is used with the Atmospheric Pressure Sensor to calculate the
boost pressure for ET.

The air/fuel ratio control is not mechanically adjustable on this engine.

SERV2742 - 27 -
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24

• Fuel Temperature The Fuel Temperature Sender (arrow) is located on the fuel manifold.
Sender (arrow) The signal from this sender is used by the Engine ECM to determine the
fuel temperature at the fuel manifold. The Engine ECM uses this
information to deliver constant power based on the fuel temperature.
SERV2742 - 28 -
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25

• Injector Connector The Injector Connector is located in the valve cover and supplies current
to all six injectors.
• Return wires paired In this 12 pin connector, nine pins are used for the injector solenoids. The
six injector return wires are paired into three pins on the connector.

INSTRUCTOR NOTE: The injector circuit is described in more

detail in STMG 712 "3406E Engine Controls--Electronic Unit
Injection (EUI)" (Form SERV1712).
SERV2742 - 29 -
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26

• Unit Injector Electronic Unit Injector

The 3406E Unit Injector is electrically and mechanically similar to the

3500 Electronic Unit Injector. The injector is controlled electrically by
the Engine ECM and is actuated mechanically. The signal from the
Engine ECM controls the opening and closing of the solenoid valve. The
solenoid valve controls the flow of high pressure fuel to the cylinder.
This system enables the Engine ECM to control fuel volume and timing.

• Injector trim codes The 3406E injector has bar codes and numerical (trim) codes marked on
the tappet. The trim code must be entered into the Engine ECM using ET.
The purpose of this code is to ensure that all injectors are matched as
perfectly as possible in performance, both in timing and fuel quantity.

If an injector is replaced, moved to another position on the engine, or if

two injectors are switched, then the injector codes must be reprogrammed.

The trim codes are programmed into the Engine ECM using ET and the
Calibrate Sensor Screen. Failure to enter the codes into a new Engine
ECM may result in unequal timing and fuel delivery between cylinders.

WARNING

The injector solenoids operate on 105 Volts Direct Current. Always

remain clear of the injector area when the engine is running or
electrical shock may occur.
SERV2742 - 30 -
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EUI INJECTOR TESTING METHODS

• Injector Solenoid Test

• Cylinder Cutout
• Automatic Injector Test

27

• Injector testing Injector Testing Review

Objective 5 These tests can be used to determine which cylinder or injector is

Visuals 27, 28
malfunctioning:

• Injector solenoid test INJECTOR SOLENOID TEST

This test is performed while the engine is stopped. The injector solenoids
can be tested automatically with the ET Service Tool using the Injector
Solenoid Test. This function individually tests each solenoid in sequence
and indicates if a short or an open circuit is present.

• Cylinder cutout test CYLINDER CUTOUT (MANUAL) TEST

This test is performed while the engine is running at any speed.

The 105 Volt Direct Current pulses can be individually cut out to aid in
troubleshooting misfire problems in the injector and the cylinder.
• Automatic injector AUTOMATIC INJECTOR TEST
test
This test is performed with the ET Service Tool while the engine is
running at any speed. The test makes a comparative evaluation of all
injectors and numerically shows the results. The test enables an
on-engine evaluation of the injectors.
SERV2742 - 31 -
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ACTIVE AND LOGGED FAULTS

• Active and logged Both Active and Logged Fault Screens should be checked. Logged Faults
faults will be shown if an intermittent electrical fault has occurred.

A satisfactory test of all injector solenoids without any diagnostic

messages means that a problem is probably mechanical and in the
cylinder.

INSTRUCTOR NOTE: The preceding injector tests can be

demonstrated in the classroom on a Training Aid (simulator) to
reinforce this portion of the lesson. This demonstration can be
performed before going to the lab where the test will be performed on
an operable engine.

The information in Lab C can be used as a basis for the classroom

demonstration.
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980G II WHEEL LOADER

3406 ENGINE CONTROLS

Lab C
Fuel Injection System
Component Removal and Installation
Testing and Adjusting

28

Introduce and perform Lab C: Fuel Injection System Component Removal, Installation,
Lab C Testing and Adjusting

Remove and install the following components on the engine:

Unit injector
Fuel transfer pump
Primary filter
Secondary filter
Fuel pressure regulating valve
Demonstrate the procedure to prime the fuel system after removal and
installation. Test and adjust the components as necessary.

Demonstrate the procedures for testing the injectors including:

Active faults
Logged faults
Solenoid test
Manual cylinder cutout with no load
Manual cylinder cutout fully loaded (i.e. torque stall)
Automatic cylinder cutout
Demonstrate injector trim code input using ET.
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3406E EUI SYSTEM (980G II)

MACHINE MOUNTED COMPONENTS
ADEM III
ELECTRONIC
CONTROL
MODULE
(ECM) GROUND DISCONNECT SWITCH
BOLT
24 V
MAIN KEY
15 AMP POWER RELAY SWITCH
BREAKER
TACHOMETER OUTPUT

THROTTLE ACCELERATOR
AIR FILTER RESTRICTION SENSOR PEDAL
LAMP

TURBO INLET PRESSURE SENSOR GROUND LEVEL SHUTDOWN

TRANSMISSION LUBE FAN CONTROL VALVE

TEMP. SENDER

+ BATTERY RELAY ETHER START VALVE

CYLINDER

CATERPILLAR MONITORING SYSTEM

ENGINE
15
10 20 P
5

X100
25
SERVICE TOOL CONNECTOR
44
CAT DATA LINK
MPH
0 km/h 30

29

• Machine block MACHINE ELECTRICAL/ELECTRONIC SYSTEMS

diagram
Machine Block Diagram

This diagram identifies the EUI electronic components mounted on the

machine.
SERV2742 - 34 -
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30

• Throttle Position The Throttle Position Sensor (arrow) is located under the throttle pedal on
Sensor (arrow) the floor of the operator’s station. The Throttle Position Sensor is a rotary
sensor which sends a Pulse Width Modulated (PWM) signal to the Engine
ECM. The Engine ECM uses this signal to determine the operator desired
engine speed.

If a fault is detected in the Throttle Position Sensor, the Engine ECM will
default to low idle engine speed.
SERV2742 - 35 -
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P2 J2
ENGINE ECM
ETHER INJECTION SYSTEM (3406)

P1 J1

3 F762-GY 21 ETHER CONTROL

229-BK

200-BK FROM
+ 1 CYLINDER
129-RD 317-YL
2
+24V
RELAY ETHER
START VALVE TO ENGINE

31

Ether Injection System

The Engine ECM controls the use of ether for cold starting. The Engine
ECM uses input signals from the speed/timing sensors and the Coolant
Temperature Sender to determine the need for ether.

The Engine ECM cycles the ether relay continuously for three seconds
• Ether injection
parameters
ON and three seconds OFF. Each time the ether relay is activated, the
valve injects 6cc of ether. Ether injection is enabled when the coolant
temperature is less than 0°C (32°F), the engine speed is below 500 rpm,
and the engine has been idling for less than ten seconds.
SERV2742 - 36 -
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32

1. Ether Start Valve The Ether Start Valve (1) is located to the rear of the Air Filter Housing.
The Engine ECM controls the Ether Start Valve to aid engine start up in
cold conditions. The solenoid on the Ether Start Valve is an on/off
solenoid.

2. Turbocharger Inlet Also shown is the Turbocharger Inlet Pressure Sensor (2). The signal
Pressure Sensor from the Turbocharger Inlet Pressure Sensor is used by the Engine ECM
to determine if the air filter is restricted. If the Engine ECM determines
that the air filter is restricted, the Engine ECM will illuminate the Air
Filter Restricted Indicator on the dash panel.
SERV2742 - 37 -
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ENGINE ECM
CAT DATA LINK

SERVICE TOOL COMMUNICATION

CONNECTOR ADAPTER

IMPLEMENT ECM
CAT
ELECTRONIC TECHNICIAN
LAPTOP
COMPUTER

POWER TRAIN ECM CATERPILLAR MONITORING SYSTEM

15
10 20 P
5
25
X100

0
MPH
km/h 30 44

33

Objective 8 CAT Data Link

Visuals 33 - 35
The CAT Data Link is the communication link between the various
• CAT Data Link
machine onboard and offboard electronic modules. The system is also
enables
communication used for programming and troubleshooting the electronic modules with
between modules and the service tool.
with service tool
The Engine ECM communicates through the CAT Data Link with the
Caterpillar Monitoring System to share engine information such as engine
speed, oil pressure, coolant temperature, and electronic system faults.

The ET Service Tool is connected through the Service Tool Connector

which allows communication with the Engine ECM, the Implement ECM,
and the Power Train ECM.
SERV2742 - 38 -
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980G II CAT DATA LINK CIRCUIT

POWER TRAIN CATERPILLAR

ECM MONITORING
SYSTEM
CAT Data Link + 9 5
CAT Data Link - 3 14 CAT Data Link +
CAT Data Link -

PAYLOAD IMPLEMENT ECM

CONTROL SYSTEM
CAT Data Link + 19 9 CAT Data Link +
CAT Data Link - 15 3 CAT Data Link -

PRODUCT LINK

CAT Data Link + 11 D SERVICE TOOL

CAT Data Link - 12 E CONNECTOR

ENGINE ECM
944-OR 8 CAT Data Link +
945-BR 9 CAT Data Link -

34

In the 980G II Wheel Loader, the following modules are connected by the
CAT Data Link:

• Seven modules Engine ECM

connected by CAT Implement ECM
Data Link Power Train ECM
Caterpillar Monitoring System
Payload Control System (if equipped)
Product Link (if equipped)
Caterpillar ET Service Tool (through the Service Tool Connector)

The CAT Data Link uses a two wire, twisted pair of cables to reduce the
effects of Radio Frequency Interference (RFI).
• CAT Data Link used On the 980G II with the ADEM III Engine ECM, the CAT Data Link is
for flash programming
now used for flash programming. The ATA data link is no longer used on
the 980G II Wheel Loader.
Troubleshooting the data link circuits is limited to checking for opens and
shorts.
SERV2742 - 39 -
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35

1. Service Ttool The 980G II Service Tool Connector (1) is located on the dash panel of
Connector the cab, to the right of the steering column.

The Service Tool Connector is used to connect the ET service tool to the
machine electronic systems. The connector allows the service tool to
access the ECMs to read diagnostic and status screen information,
perform calibrations, and other functions.

2. 12 Volt Power Above the Service Tool Connector is the 12 Volt Power Supply
Supply Connector Connector (2) for a laptop.

3. Air Filter Also pictured is the Air Filter Restricted Indicator (3). This indicator is
Rrestricted illuminated by the Engine ECM.
Indicator
SERV2742 - 40 -
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DEMAND FAN SYSTEM CIRCUIT

ENGINE ECM
P2 J2
833-PK 18 TEMP SEND COMM
COOLANT TEMP SENDER
995-BU 32 COOLANT TEMP
967-BU 35 INLET AIR TEMP
INLET AIR TEMP SENDER P1 J1
843-PU 3 TEMP SEND COMM
944-OR 8 DATA LINK
TRANS LUB TEMP SENDER 9 DATA LINK
945-BR
971-YL 26 TRANS LUB TEMP
746-YL 43 FAN CONTROL
747-BR 51 FAN CONTROL
FAN CONTROL VALVE

944-OR 5 DATA LINK

442-GY 10 HYD TEMP
HYDRAULIC TEMP SENSOR 945-BR 14 DATA LINK
201-BK 933-GN 24 +8V SENS SUPPLY

CATERPILLAR MONITORING
SYSTEM ECM

36

Demand Fan System

The Engine ECM controls the speed of the cooling fan. The Engine ECM
uses input signals from the Coolant, Inlet Air, and Transmission
Lubrication Temperature Senders, and from the Hydraulic Temperature
Sensor to determine the desired speed of the cooling fan. The Engine
ECM sends a PWM signal to the Fan Control Valve to maintain the
desired cooling fan speed.
SERV2742 - 41 - Slide/Text Reference
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37

1. Hydraulic Fan The Hydraulic Fan Pump (1) and the Fan Control Valve (2) are located on
Pump the right side of the machine, near the Fuel Transfer Pump. The Engine
2. Fan Control Valve ECM sends a variable PWM signal to the Fan Control Valve which
modulates the pressure of the signal oil to the variable displacement
Hydraulic Fan Pump.

In order to increase the speed of the Cooling Fan, the Engine ECM
decreases the PWM signal to the Fan Control Valve solenoid. In order to
decrease the speed of the Cooling Fan, the Engine ECM increases the
PWM signal to the Fan Control Valve solenoid. If the Fan Control Valve
solenoid fails, the Cooling Fan is driven at maximum speed.
SERV2742 - 42 -
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38

• Transmission The Transmission Lubrication Temperature Sender (arrow) is located on

Lubrication the left side of the machine, near the Power Train Oil Cooler. The Engine
Temperature Sender
ECM uses the signal from this sender to determine the temperature of the
(arrow)
transmission lubrication oil. The temperature of the transmission
lubrication oil is one of variables used to determine the desired speed of
the Cooling Fan.
SERV2742 - 43 -
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39

• Hydraulic Oil The Hydraulic Oil Temperature Sensor (arrow) is located on the right side
Temperature Sensor of the machine on the hydraulic tank. The Engine ECM receives the
(arrow)
signal from this sensor through the Caterpillar Monitoring System ECM
over the CAT Data Link. The temperature of the hydraulic oil is one of
variables used to determine the desired speed of the Cooling Fan.
SERV2742 - 44 -
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40

Ground Level Shutdown Switch

• Ground Level The Ground Level Shutdown Switch (arrow) is located in the toolbox on
Shutdown Switch the left side of the machine. This switch enables the engine to be shut
(arrow) down externally for safety reasons. To operate the switch, lift the cover
and move the switch to the upper position.

The switch also may be used to disable the injectors during cranking for
maintenance purposes. To reset the switch, the key switch must be cycled
through the OFF position for a few seconds, and then to the ON position
after the ground Level Shutdown Switch is returned to the down position.

The status of the switch may be checked using the ET Status Screen.
SERV2742 - 45 -
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ENGINE DERATES AND

AUTOMATIC POWER ADJUSTMENTS
• Altitude Derate
• High Coolant Temperature Derate
• High Inlet Air Temperature Derate
• Low Oil Pressure Derate
• Fuel Temperature Compensation
• Constant Net Horsepower

41

Engine Derates and Automatic Power Adjustments

• Engine derates This visual shows the various automatic derates and fuel system
corrections which apply to this engine application.

Altitude Derate protects the engine against the effects of overfueling

when there is insufficient air to burn the fuel. The derate starts at 7900 ft
with a maximum of 26% derate at 16000 ft.

High Coolant Temperature Derate protects the engine from the effects of
high coolant temperatures. Engine power is derated 12.5% at 109°C
(228°F) with a maximum derate of 25% at 110°C (230°F).

High Inlet Air Temperature Derate protects the engine from the effects of
high inlet air temperatures. The derate starts at 80°C (176°F) and derates
3% per °C up to 86°C (187°F) at which the maximum derate of 20%
occurs.
SERV2742 - 46 -
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Low Oil Pressure Derate protects the engine from the effects of low oil
pressure. The chart below specifies at what oil pressure and engine speed
the derate begins. If the engine has low oil pressure for 3 seconds the
derate is 17.5%, at 5 seconds the derate is 35%.

600 rpm 0 kpa ( 0 psi)

800 rpm 50 kpa ( 7 psi)
1400 rpm 100 kpa (15 psi)
1700 rpm 150 kpa (22 psi)
2100 rpm 200 kpa (29 psi)

Fuel Temperature Compensation is used to maintain power at a constant

level regardless of fuel temperature variations between 30°C (86°F) and
90°C (194°F).

Constant Net Horsepower is used by the Engine ECM to deliver the

engine’s rated horsepower regardless of fan speed. When the fan is
driven at maximum speed the engine will operate at the higher valued
rack limits. When the fan is driven at minimum speed the engine will
operate at lower rack limits. At fan speeds between maximum and
minimum the Engine ECM will interpolate between the two torque maps.
SERV2742 - 47 -
8/03

3406E ENGINE EVENTS

• High Coolant Temperature Warning
• High Inlet Air Temperature Warning
• Low Oil Pressure Warning
• High Fuel Pressure Warning
• Low Fuel Pressure Warning
• Engine Overspeed Warning

42

3406E Engine Events

• Engine events
Events are situations where the engine is running outside its normal
operating parameters.
SERV2742 - 48 -
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43

• Seven major Major Component Review

component types:
This visual shows seven of the major types of components or circuits in
- Speed/Timing the EUI fuel system. From left to right, the components are:
Sensor
- Speed/Timing Sensor
- Throttle Position
Sensor - Throttle Position Sensor
- Engine ECM
- Engine ECM
- Injector
- Injector
- Pressure Sensor
- Pressure Sensor
- Temperature Sensor
- Temperature Sensor
The CAT Data Link (not shown) provides a two-way communication path
- CAT Data Link
between the Engine ECM system and the remaining electronic circuits or
systems on the machine. The CAT Data Link also allows the service tool
to communicate with the machine electronic system.

NOTE: Only one example of each sensor and injector is shown on

the visual.
SERV2742 - 49 -
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Lab D: Electric/Electronic
Component Identification

Lab E: Electric/Electronic Component

Removal, Installation,
Testing and Adjusting

Lab F: General System Diagnostics

44

Introduce and perform Lab D: Electric/Electronic Component Identification

Lab D
Objective 4 Identify the components on the machine engine. Assist the students in
explaining the function of each component.

Identify and explain the functions of the major electronic and electrical
components and systems listed on the Lab D worksheet.

Introduce and perform Lab E: Electric/Electronic Component Removal, Installation, Testing

Lab E and Adjusting
Objectives 6, 7, and 9

Students will remove, install and perform functional tests on the

electronic and electrical components and systems listed on Lab E
Worksheet.

Introduce and perform

Lab F Lab F: General System Diagnostics
Objective 10
Students will evaluate and diagnose a low power problem and a failure to
start condition described on Lab F Worksheet.

Students will make recommendations for, and perform the repair.

SERV2742 - 50 - Visual List
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VISUAL LIST
1. Title visual 39. Hydraulic oil temperature sensor
2. Machine view 40. Ground level shutdown switch
3. Major components 41. Engine derates and automatic power
4. Engine compartment right view adjustments
5. Engine compartment left view 42. 3406 engine events
6. Lab A 43. Major component review
7. 3406 fuel delivery system 44. Labs D, E, and F
8. Primary fuel filter
9. Fuel priming pump
10. Fuel transfer pump
11. Fuel manifold
12. Engine ECM
13. Secondary fuel filter
14. Fuel pressure regulator valve
15. Lab B
16. 3406 engine block diagram
17. Engine ECM
18. Camshaft speed/timing sensor
19. Coolant temperature sender
20. Fuel pressure sensor
21. Inlet air temperature sender and
Atmospheric pressure sensor
22. Oil pressure sensor
23. Turbocharger outlet pressure sensor
24. Fuel temperature sender
25. Injector connector
26. Unit injector
27. EUI injector testing methods
28. Lab C
29. 3406 machine block diagram
30. Throttle position sensor
31. Ether injection system
32. Ether start valve and Turbocharger inlet
pressure sensor
33. CAT Data Link
34. 980G II CAT Data Link circuit
35. Service tool connector
36. Demand fan circuit
37. Hydraulic fan pump and Fan control valve
38. Transmission lubrication temperature sender