SERV1833

March 2007

GLOBAL SERVICE LEARNING

TECHNICAL PRESENTATION

"C" SERIES SKID STEER LOADERS

246C/256C/262C/272C
AND
MULTI-TERRAIN LOADERS
277C/287C/297C
INTRODUCTION

Service Training Meeting Guide

(STMG)
"C" SERIES SKID LOADERS
246C/256C/262C/272C AND MULTI-
TERRAIN LOADERS 277C/287C/297C
INTRODUCTION

AUDIENCE

Level II - Service personnel who understand the principles of machine system operation,
diagnostic equipment, and procedures for testing and adjusting.

CONTENT

This presentation provides an overview of the "C" Series Skid Steer Loaders and Multi-Terrain
Loaders Field Follow Machines. This presentation may be used for self-paced and self-directed
training.

OBJECTIVES

After learning the information in this meeting guide, the serviceman will be able to:
1. identify the new service and maintenance features on the "C" Series Skid Steer Loaders
and Multi-Terrain Loaders;
2. operate the machine using the new controls for machine travel and work tool functions;
3. operate the instrument cluster screen in the operator mode and service mode;
4. locate and identify the new components on the "C" Series Skid Steer Loaders and Multi-
Terrain Loaders;
5. explain the basic operation of the new machine systems; and
6. identify the new Cat ET screens used to diagnose the machine systems.

REFERENCES

STMG "B" Series Skid Steer Loaders and Multi-Terrain Loaders -

Machine Systems Operation SERV1783

Estimated Time: 8 Hours

Visuals: 77
Handouts: 8
Form: SERV1833
Date: 03/07

© 2007 Caterpillar Inc.

SERV1833 -3- Text Reference
03/07

TABLE OF CONTENTS

INTRODUCTION ........................................................................................................................5
Similarities and Differences ...................................................................................................8

OPERATOR'S STATION..............................................................................................................9

ENGINE......................................................................................................................................34

ELECTRICAL SYSTEM ...........................................................................................................39

Interlock Strategy..................................................................................................................47

POWER TRAIN .........................................................................................................................49

WORK TOOL HYDRAULIC SYSTEM ...................................................................................66

CONCLUSION...........................................................................................................................82

VISUAL LIST ............................................................................................................................83

HYDRAULIC SCHEMATIC COLOR CODE...........................................................................84

HANDOUTS...............................................................................................................................85
SERV1833 -4- Text Reference
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NOTES
SERV1833 -5- Text Reference
03/07

"C" SKID STEER LOADERS

246C/256C/262C/272C
AND
MULTI-T
TERRAIN LOADERS 277C/287C/297C

© 2007 Caterpillar Inc.

INTRODUCTION

The 246C/256C/262C/272C Skid Steer Loaders and the 277C/287C/297C Multi-Terrain

Loaders are the latest generation of Caterpillar Skid Steer Loaders and Multi-Terrain Loaders
retaining many of the features proven on the "B" Series machines along with additional
performance and design improvements.

The cab has been redesigned and includes a digital display panel.

The hydrostatic drive system and work tool hydraulic system are electronically controlled by
the Machine Electronic Control Module (ECM). The Machine ECM controls all the functions
that the Operator Interlock ECM and Auxiliary Hydraulic ECM controlled on the "B" Series
machines. The Machine ECM controls additional functions in the "C" Series machines.

The high flow hydraulic system is now optional on all 246C/256C/262C/272C Skid Steer
Loaders and 277C/287C/297C Multi-Terrain Loaders.

Ride Control has been added as an option on all "C" Series machines.

This presentation discusses the new components and features of the 246C/256C/262C/272C
Skid Steer Loaders and the 277C/287C/297C Multi-Terrain Loaders.

The "C" Series product line brings significant improvements in performance, operator comfort,
controllability, versatility, and styling.
SERV1833 -6- Text Reference
03/07

KEY NEW FEATURES

- Operator's Station
- Electronically Controlled Hydrostatic Drive System
- Electronically Controlled Work Tool Hydraulic System
- Improved Electrical System
- Ride Control System
- High Flow Hydraulic XPS System Optional on all Machines
- Creeper Control
- Two-speed Option
- Tough Guard Hoses
- Undercarriage with Optional Dual Level Suspension

The "C" Series Skid Steer Loaders and Multi-terrain Loaders are equipped with several new
features as shown in this illustration.

The operator's station has been redesigned with several new controls and a digital display panel
that can display machine information, and change three operator modes and seven service
modes.

The hydrostatic drive system is electronically controlled by the Machine ECM. The joysticks
in the cab send signals to the Machine ECM, which sends corresponding signals to the pump
control solenoids to control pump output.

The work tool hydraulic system is also electronically controlled by the Machine ECM. The
joysticks in the cab send signals to the Machine ECM, which sends corresponding signals to the
work tool lift, tilt, and auxiliary solenoids. The solenoids control the work tool directional
spools, which control oil to the lift and tilt cylinders and the auxiliary circuit.

The electrical system includes a new single Machine ECM, which controls many more machine
functions than the "B" Series machines.
SERV1833 -7- Text Reference
03/07

Ride Control has been added as an option on the Skid Steer Loaders. The Ride Control System
operates similarly to current Caterpillar wheel loaders.

The optional high flow (XPS auxiliary) hydraulic system is now optional on all "C" Series
machines.

A creeper control function has been added, which allows the operator to select a maximum
machine travel speed at full joystick movement.

The two-speed function is optional on all machines and includes a redesigned travel motor.

Cat ToughGuard™ hydraulic hoses provide excellent abrasion resistance, which exceeds the
capabilities of standard hydraulic hoses.

The undercarriage has been redesigned with greater serviceability, torsional axles, and when
fitted, the optional dual level suspension utilizes four independently pivoting bogie axles for
smoother travel.
SERV1833 -8- Text Reference
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SIMILARITIES AND DIFFERENCES

FEATURES DIFFERENT SIMILAR SAME
Machine Appearance X
Operator's Station X
Engine X
Electrical X
Hydrostatic Drive System X
Work Tool Hydraulic System X
Undercarriage X
Maintenance Items X

Similarities and Differences

The chart above shows the similarities and differences between the new
246C/256C/262C/272C Skid Steer Loaders and 277C/287C/297C Multi-Terrain Loaders and
the current "B" Series machines.
SERV1833 -9- Text Reference
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OPERATOR'S STATION

The new Skid Steer Loader cab provides optimal space. For machines equipped with the
optional enclosed cab (as shown in this illustration), a new door provides the operator with
greater visibility to the work tool. The new cab is sealed and has a positive pressure. The cab
comes radio ready and the dead engine lower function is now performed from the cab.

A Rollover Protective Structure (ROPS) cab is standard. A Falling Object Protective Structure
II (FOPS II) cab is available as an option. The FOPS II cab can be used for applications that
require protection from large, heavy, falling objects.

The top window is bonded and cannot be removed, which improves reliability against leaks and
dust entering the cab.
SERV1833 - 10 - Text Reference
03/07

The cab can be raised by removing two bolts at the front of the cab, which allows easy access
to components. The bolt (arrow) on the right side of the machine is shown in this illustration.
The cab rotates up as a complete unit.
SERV1833 - 11 - Text Reference
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3
2
5

3 1

The top illustrations show the air conditioning ducting. Air flows into the machine through the
fresh air inlet (1). Air flows into the evaporator compartment (2) through a duct (3) below the
cab. The air passes over the evaporator (4) and is cooled. The cooled air is routed into the cab
through a duct (5) on the bottom of the cab.

The bottom right illustration shows the evaporator housing (6) removed from the machine.
SERV1833 - 12 - Text Reference
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3 2

This cab is equipped with a mechanical suspension seat.

There are two armrests (1) in the "C" Series machines, which rotate from side-to-side. In this
illustration the armrests are shown in the UP position.

The seat can be moved back and forth with the seat lever (2) below the left side of the seat.
The knob (3) located below the center of the seat cab be turned to adjust the seat suspension.
SERV1833 - 13 - Text Reference
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3 2

In this illustration the armrests (1) are shown in the DOWN position.

This cab is equipped with an optional air suspension seat. The seat can be moved back and
forth with the seat lever (2) below the left side of the seat. The knob (3) located below the
center of the seat can be pulled in or out to adjust the seat suspension by operating an internal
pump to inflate the seat bladder.
SERV1833 - 14 - Text Reference
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6
4
2

The left and right joysticks are adjustable independently from the seat. The joystick adjustment
lever (1) is located to the rear of the joystick.

In the standard control lever pattern, the left joystick (2) provides directional control and has
the same function as previous models. The switches on the left joystick are:
- horn (3)
- auxiliary electrical control "C2" (4)
- auxiliary electrical control "C1" (5)
- continuous flow control (6)
The trigger switch (not visible) located on the front side of joystick is used to control the
two-speed function or the auxiliary electrical function "AUX 7." The multifunction switch on
the left overhead console determines the functionality of the trigger switch.
SERV1833 - 15 - Text Reference
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5
3
2

10

The right joystick adjustment lever (1) is located to the rear of the joystick.

In the standard control lever pattern, the right joystick (2) provides work tool control and
functions the same as previous models.
The thumb switch (3) controls the proportional auxiliary hydraulics or the high flow auxiliary
hydraulics if the auxiliary hydraulic mode switch is in the HIGH FLOW position.

The switches to the right of the thumb switch operate the work tool control circuit found on
high flow machines. The top switch (4) activates the "C+" function. The bottom switch (5)
activates the "C-" function.

A trigger switch (not visible) on the front of the joystick controls the FLOAT function as the
joystick is now an electronic control and there is no detent position.
SERV1833 - 16 - Text Reference
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AUXILIARY FUNCTIONS
STANDARD CONFIGURATION
C1 C2

C D E
A2
B A
H G F

Work Tool Electrical Connector

Electrical Pin Arrangement
A1 Connector

Auxiliary Hydraulic
Connections

C1 Aux 6
Thumb Switch
(A1/A2 Aux)

C2 Aux 5
Left Joystick Right Joystick

11

This illustration shows the joystick controls and the auxiliary hydraulic and electrical
connections on machines with a standard hydraulic configuration.

The thumbswitch on the right joystick controls proportional hydraulic oil flow to the loader
arms through the A1 and A2 connectors.

The C1 switch on the left joystick provides electrical power to some work tools through pin C
on the work tool electrical connector. The C2 switch on the left joystick provides electrical
power to some work tools through pin D on the work tool electrical connector.
SERV1833 - 17 - Text Reference
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Work Tool
Electrical Connector
Return AUXILIARY FUNCTIONS
HIGH FLOW CONFIGURATION
C+
C-

High Flow High Flow (A2)

C1 C2
(A1)

Standard Standard (A2) C D E

(A1) Aux 7 B A
H G F

Electrical Connector
Pin Arrangement

Auxiliary Hydraulic Connections

C+ Aux 4
C2 Aux 6
Thumb Switch
(A1 / A2 Aux)
Aux 7
Trigger Switch
C1 Aux 5 C- Aux 3
Left Joystick Right Joystick

12

This illustration shows the joystick controls and the auxiliary hydraulic and electrical
connections on machines equipped with a high flow hydraulic configuration.

The thumbswitch on the right joystick controls proportional hydraulic oil flow to the loader
arms through the A1 and A2 connectors. For standard work tools, oil is provided through the
standard A1 and A2 hydraulic connectors. For high flow work tools, oil is provided through the
high flow A1 and A2 hydraulic connectors.

The C+ and C- switches on the right joystick control ON/OFF hydraulic oil flow to the loader
arms through the C+ and C- connectors.

The C1 switch on the left joystick provides electrical power to some work tools through pin C
on the work tool electrical connector. The C2 switch on the left joystick provides electrical
power to some work tools through pin D on the work tool electrical connector.

The trigger switch provides electrical power to some work tools through pin B on the work tool
electrical connector when the multifunction switch on the left overhead console is in the
AUX 7 position.
SERV1833 - 18 - Text Reference
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CONTROL LEVER PATTERNS

Standard Bucket
Foward Lower

Left Right Tilt Tilt

Turn Turn Backward Forward

Reverse Bucket
Raise

Optional LH Forward RH Forward

Bucket Bucket Tilt Tilt

Raise Lower Backward Forward

LH Reverse RH Reverse

13

Two control patterns are available for the "C" Series machines. The control patterns are
software enabled. The Standard pattern is the same pattern used on the former machines. The
optional pattern provides an alternative control pattern with the convenient control and feel of
dual control lever steering and work tool controls.

Films in the operator's compartment identify the installation of the optional pattern on a
machine.
SERV1833 - 19 - Text Reference
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1 2
3

8
9

7
6 10

14

The fuse panel (1), the document compartment (2), the recirculation filter (3), and the radio (4)
are all located at the rear of the cab.

NOTE: All machines are equipped with radio wiring and a radio mounting location.
However, the radio is a dealer installed component.

The armrest switch (5) is located below the left armrest. The armrest must be down to activate
the hydraulic controls.

The fuse panel includes fuses (6) and 10 relays (7). The fuse panel cover (8) includes a decal.
A lanyard is attached to the fuse panel and cover. The Cat ET connector (9) is located above
the fuse panel.

A pleated cab recirculation filter (10) replaces the foam recirculation filter used on the
"B" Series machines.
SERV1833 - 20 - Text Reference
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15

The cab fresh air filter is located on the left side at the rear of cab. Remove the filter
cover (arrow) to service the filter element.
SERV1833 - 21 - Text Reference
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16

Lifting hooks (arrows) can be attached to optional mounts on the top of the cab for lifting the
machine. A four-point lifting kit is optional.
SERV1833 - 22 - Text Reference
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17

2
18

The governor control lever (1) is shown in the top illustration and the accelerator pedal (2) is
shown in the bottom illustration.

A new throttle position sensor (not shown) is located on the accelerator pedal assembly.
SERV1833 - 23 - Text Reference
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2 1

19

The throttle position sensor (1) is located at the base of the accelerator pedal assembly (2). The
throttle position sensor sends a signal to the Machine ECM indicating the accelerator pedal
position. The throttle position signal is used by the Machine ECM to control machine
underspeed conditions.
SERV1833 - 24 - Text Reference
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20

This illustration shows the relocated windshield washer reservoir (arrow).

SERV1833 - 25 - Text Reference
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21

A dead engine lower knob (arrow) has been installed in the cab to allow the lift arms to be
lowered from inside the cab in the event of a dead engine and no electrical power or in the
event of an uncharged accumulator.
SERV1833 - 26 - Text Reference
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1
22

6
23

In a situation where the operator is unable to lower the lift arms, there is an unlocking
mechanism built into the door. To remove the door, the gas strut (1) must be removed, the top
handle (2) pulled up and the bottom handle (3) pulled down.

A decal (4) is located on the door post that shows the door removal procedure.

NOTE: For the complete door removal procedure, refer to the "C" Series Operation
and Maintenance Manual.

Also visible in the bottom illustration is the windshield washer switch (5) and the door
switch (6). The door switch prevents lift arm movement while the door is open. Inadvertent
lift arm movement could damage the door.
SERV1833 - 27 - Text Reference
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1 2 3 4 5 6 7 8

24

The left overhead console includes the following switches:

-Auxiliary hydraulic pressure release (1)

-Hydraulic lockout and interlock override (2)

-Rear work lights (3)

-Front work lights (4)

-Auxiliary 7/two-speed selection switch (5)

-Auxiliary electrical control (6)

-Automatic level control (7)

-Work tool coupler control (8)

SERV1833 - 28 - Text Reference
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9 10
7
8

4
25

3 2

10

8
5

26
6
4

The left overhead display includes the key start switch (1), the 12 volt receptacle (2), the
parking brake switch (3), and the joystick control pattern switch (4, if equipped). If the pattern
switch is installed, Caterpillar pattern No.1 (5), or alternate pattern No. 2 (6) must be selected
to release the parking brake.

A digital display panel (7) includes the warning indicators (8), the fuel level gauge (9), and the
service hour meter (10).

The bottom illustration shows the warning indicators illuminated. There are three warning
levels. With a Level 1 warning, the alert indicator is ON continuously. With a Level 2
warning, the alert indicator flashes. With a Level 3 warning, the alert indicator flashes and a
warning alarm sounds.
SERV1833 - 29 - Text Reference
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27
1 2 3

4 28
5

The heating and air conditioning controls have been moved to the right overhead console. The
switches include the fan speed control switch (1), the air conditioning control switch (2), and
the temperature control switch (3).

To the left of the heating and air conditioning controls are the creeper control switch (4), and
the optional ride control switch (5). The creeper control switch allows the operator to select a
maximum machine travel speed at full joystick movement.
SERV1833 - 30 - Text Reference
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2
3

5 4
29
6

30

The right overhead display panel includes an optional digital display panel (1) with a coolant
temperature gauge (2) and a hydraulic oil temperature gauge (3). A digital display window (4)
is used to display machine information.

The switches below the digital display panel include the beacon switch (5), the hazard
flashers (6), the optional roading lights (7), and the optional turn signals (8).

The bottom illustration shows all the available icons that can be displayed on the digital display
window.
SERV1833 - 31 - Text Reference
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31

The right overhead display will show machine information in three Operator Modes and eight
Service Modes. The function selector key (1) is used to toggle between available modes. The
scroll up key (2) and scroll down key (3) are used to toggle between screens or settings within
a mode.

The three Operator Modes are:

- Mode 1 (Display Screen): displays basic machine information including engine speed
(default start-up mode shown in the top right illustration), system voltage, and job clock.

- Mode 2 (Implement Control): displays the current lift and tilt function response setting
(bottom left illustration). The three implement response settings are Fine Control,
Medium Control, and Course Control. Fine control is one bar, medium control is two
bars, and course control is three bars. The default setting is medium. Fine control
provides a more precise implement response.

- Mode 3 (Creeper Control): displays the current creeper control setting (bottom right
illustration). There are 10 creeper settings, which allow the maximum machine travel
speed to be set between 5% and 100% of full speed.
SERV1833 - 32 - Text Reference
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32

2 1

33

2 1

These illustrations show the display panel in the Service Mode. To display the Service Mode
press and hold the function select key (1) and the scroll up key (2) for at least three seconds.
The function select key allows navigation between modes and the arrows keys allow navigation
within each mode.The eight Service Modes are:

- Mode 0 (Active Diagnostics): displays the active diagnostic codes. If no active faults are
present the display will show "0 - 0" (top illustration). The bottom illustration shows an
active diagnostic code.

- Mode 1 (Logged Diagnostics): displays the logged diagnostic codes.

- Mode 2 (Active Events): displays the active event codes.

SERV1833 - 33 - Text Reference
03/07

- Mode 3 (Logged Events): displays the logged event codes.

- Mode 4 (Software P/N Machine): displays the currently installed Machine ECM
software part number.

- Mode 5 (Machine Parameters): displays the engine coolant temperature, the hydraulic oil
temperature, and the left and right drive motor speed and direction.

- Mode 6 (Component Status): displays the status of the throttle position, the joystick
position, the parking brake switch, the backup alarm relay, the stop lamp relay, and the
ride control status.

- Mode 7 (Units): allows the units to be set to Metric or English.

SERV1833 - 34 - Text Reference
03/07

5 6 7

3
1 2 8

9
4

5 6
9
8

4
4

11
10

34

ENGINE

The 3044C engine is similar to the "B" Series machines. The engine ratings have been
increased and an ATAAC has been added to the 272C and 297C machines to increase power.
The bottom views show the front of the engine with the engine cover removed. The following
components have new locations in the engine compartment:

- Hydraulic oil filter (1)

- Maintenance and lubrication points decal (2)

- Engine coolant reservoir (3)

- Fuel filter and priming pump (4)

- Jump start receptacle (5)

- Oil filler cap - (relocated from the front timing cover to the valve cover, (6)

- Air cleaner decal (7): A decal has been added to the air filter housing to ensure proper
installation. The dust ejector must also be checked daily to ensure it is not plugged.
SERV1833 - 35 - Text Reference
03/07

- Fuel tank and filler cap (8)

- Engine oil dipstick (9)

- Air conditioning compressor (10): The compressor has been moved into the engine
compartment and is now driven by a belt.

- Engine oil filter (11)

SERV1833 - 36 - Text Reference
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35

The oil filter (arrow) is now mounted vertically for improved serviceability. The "C" Series
engine is equipped with an open breather system.
SERV1833 - 37 - Text Reference
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2
3

36

37

An Air to air aftercooler (ATAAC) (1) has been added to the 272C Skid Steer Loader and the
297C Multi-Terrain Loader. The ATAAC housing (2) and hydraulic drive motor (3) for the
ATAAC fan are located at the back of the engine compartment behind the cab. The ATAAC
motor is driven by oil from the ATAAC pump (not shown) which is mounted to the charge
pump.

The ATAAC fan forces air through the aftercooler and out the top of the engine compartment.
Debris can be cleaned from the ATAAC by opening a panel (4) behind the cab.

Also located inside the ATAAC housing is the air conditioning condenser.
SERV1833 - 38 - Text Reference
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38

In cold weather, the glow plugs are powered by the Machine ECM through the cold start relay
when the key start switch is turned to the ON position. The glow plug indicator (arrow) on the
left overhead console will illuminate when the key start switch is turned on and go out when the
engine is ready to start.

The ECM will monitor both the engine coolant temperature and the hydraulic oil temperature.
If either temperature is below the preset value, the glow plugs will be activated.
SERV1833 - 39 - Text Reference
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39

ELECTRICAL SYSTEM

The battery has been relocated under the cab from the engine compartment. A remote jump
start receptacle is located in the engine compartment as previously described.
SERV1833 - 40 - Text Reference
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2 2

40

The single Machine ECM (1) is located at the back of the cab. Two power relay modules (2)
and six fuses (not visible) are also located behind the cab. The fuses are accessed by removing
the fuse covers (3).

The Machine ECM is an A4:M1 ECM with two 70-pin connectors.

The Machine ECM on the "C" Series machines replaces the Operator Interlock ECM and
Auxiliary Hydraulic ECM on the "B" Series machines.
SERV1833 - 41 - Text Reference
03/07

MACHINE ECM INPUTS AND OUTPUTS

Key Start Switch
Two Speed Solenoid
Engine Speed Sensor
Engine Coolant Temperature Sensor Left Hystat Pump Forward Solenoid
Hydraulic Oil Temperature Sensor Left Hystat Pump Reverse Solenoid
Fuel Level Sensor Right Hystat Pump Forward Solenoid
Armrest Switch
Right Hystat Pump Reverse Solenoid
Continuous Flow Switch
Auxiliary Valve Solenoid 1
Auxiliary Hydraulic Pressure Release Switch
Battery Auxiliary Valve Solenoid 2
High Pressure Tool Detent Switch Demand Fan Solenoid
Engine Oil Pressure Switch Tilt Up Implement Solenoid
Hydraulic Lockout Switch Tilt Down Implement Solenoid
Creeper Control Switch
Lift Implement Solenoid
Alternator R Terminal
Lower Implement Solenoid
Air Cleaner Indicator Switch
Pilot ON / OFF Solenoid
Throttle Level Position Sensor
Machine Load Sense Relief Valve Solenoid (XPS)
Aux 1 / Aux 2 RLR or Aux 2 Switch
ECM Implement Pilot Solenoid
Ride Control Switch
Start Relay
Aux 1 Switch
Cold Start Relay
Door Switch
Stop Lamp Relay
RH Joystick Trigger Switch
RH Joystick C+ Switch Back-up Alarm Relay
Fuel Pump Relay
LH Joystick Fore / Aft Switch
Ride Control Self Level Relay
LH Joystick Side / Side Switch
Cold Start Advance Relay
Left Motor Speed Sensor
Right Motor Speed Sensor
CAT ET
Hydraulic Filter Bypass Switch CAT Data Link
RH Joystick Fore / Aft Switch Product Link
RH Joystick Side / Side Switch CAN Data Link (If Equipped)
Pattern Change Switch
Two Speed Switch Instrument
Park Brake Switch Clusters
Interlock Override Switch
Seat Switch

41

This illustration shows the Machine ECM inputs and outputs. There are several more machine
functions that are controlled by the Machine ECM in the "C" Series machines.

The Machine ECM controls the following hydrostatic drive features:

-two-speed control
-Creeper control
-Joystick steering and speed control
-Neutral interlock
-Underspeed control
-Power management control
-Fault management control
-Uncommanded track movement detection
-Differential speed ratio control
SERV1833 - 42 - Text Reference
03/07

The Machine ECM controls the following work tool hydraulic system features:
-Auxiliary bleed off control
-Auxiliary tool control
-Bucket tilt control
-Lift arm raise/lower control
-Continuous flow control
-Interlock override control
-Joystick pattern changer
-Ride control

The Machine ECM controls the following machine system features:

-Engine start interlock
-Glow plug start control
-Hydraulic demand fan control
SERV1833 - 43 - Text Reference
03/07

42

Cat ET can be used for configuring and diagnosing the "C" Series machines. This screen shows
the Machine status screen. Several status screen are available to aid in troubleshooting
Machine ECM controlled functions. The screens are:

- Machine
- Interlock
- Engine
- Hystat inputs
- Hystat outputs
- Hystat control
- Implement control
- Auxiliary hydraulics
- High flow
- Joystick
SERV1833 - 44 - Text Reference
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43

This illustration shows the machine Configuration screen. Several "C" Series machine features
can be installed using the Configuration screen.
SERV1833 - 45 - Text Reference
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44

The following components can be calibrated using Cat ET:

- Throttle position sensor

- Joystick control levers
- Work tool hydraulic system solenoids
- Hystat pump solenoids
- Demand fan solenoid
SERV1833 - 46 - Text Reference
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45

The Machine ECM, left console display, and right console display can all be flashed using the
Cat ET WinFlash program.
SERV1833 - 47 - Text Reference
03/07

MACHINE ECM INPUTS AND OUTPUTS

Key Start Switch Two Speed Solenoid
Engine Speed Sensor Left Hystat Pump Forward Solenoid
Engine Coolant Temperature Sensor Left Hystat Pump Reverse Solenoid
Hydraulic Oil Temperature Sensor
Right Hystat Pump Forward Solenoid
Fuel Level Sensor
Right Hystat Pump Reverse Solenoid
Armrest Switch
Continuous Flow Switch Auxiliary Valve Solenoid 1

Auxiliary Hydraulic Pressure Release Switch Auxiliary Valve Solenoid 2

Battery Demand Fan Solenoid

High Pressure Tool Detent Switch Tilt Up Implement Solenoid
Engine Oil Pressure Switch Tilt Down Implement Solenoid
Hydraulic Lockout Switch Lift Implement Solenoid
Creeper Control Switch Lower Implement Solenoid
Alternator R Terminal
Pilot ON / OFF Solenoid
Air Cleaner Indicator Switch
Load Sense Relief Valve Solenoid (XPS)
Throttle Level Position Sensor
Machine Implement Pilot Solenoid
Aux 1 / Aux 2 RLR or Aux 2 Switch ECM
Ride Control Switch Start Relay

Aux 1 Switch Cold Start Relay

Door Switch Stop Lamp Relay
RH Joystick Trigger Switch Back-up Alarm Relay
RH Joystick C+ Switch Fuel Pump Relay
LH Joystick Fore / Aft Switch Ride Control Self Level Relay
LH Joystick Side / Side Switch
Cold Start Advance Relay
Left Motor Speed Sensor
Right Motor Speed Sensor CAT ET
CAT Data Link
Hydraulic Filter Bypass Switch Product Link
RH Joystick Fore / Aft Switch CAN Data Link (If Equipped)
RH Joystick Side / Side Switch
Pattern Change Switch Hydraulic Lockout Lamp
Two Speed Switch Park Brake Lamp
Park Brake Switch
Armrest / Seat Lamp
Interlock Override Switch
Seat Switch

46

Interlock Strategy

The interlock strategy is similar to the "B" Series machines, but is now controlled by the
Machine ECM. This illustration shows the input and output components (red) used to control
the interlock function.

The Machine ECM prohibits the engine from starting and de-energizes the pilot ON/OFF
solenoid valve and the implement pilot shutoff solenoid valve until certain conditions are met.
The Machine ECM disables the work tool hydraulic system until the operator is seated with the
armrest down, the door closed, the hydraulic lockout switch off, and the park brake released.

The Machine ECM reads the input signals from various switches on the machine. The armrest
switch is a normally open switch located at the hinge point for the left armrest. The armrest
switch closes when the left armrest is lowered. The seat switch is a normally open switch that
is located below the operator's seat. The seat switch closes when the operator is seated in the
seat. The door switch is a normally open switch located on the inside of the door. The door
switch closes when the door is closed.
SERV1833 - 48 - Text Reference
03/07

The Machine ECM determines operator requests from input signals from the key start switch,
the park brake switch, and the hydraulic lockout switch.

The Machine ECM controls engagement of the starter motor. The start relay is powered by the
Machine ECM when the following inputs are seen: the key start switch, the armrest switch,
and the seat switch.

An open circuit on the key start switch input disables machine starting. A short to ground on
the key switch input blows a fuse, disabling machine starting. A short to battery on the key
start switch input causes the start relay to be continuously energized as long as the armrest
switch and seat switch remain in the closed position.

An open circuit or short to ground to the start relay disables machine starting. Shorts to battery
in the start relay circuit cause the start relay to be continuously energized, resulting in starter
motor damage.

The implement pilot shutoff solenoid and park brake solenoid are energized by the Machine
ECM when the park brake switch is depressed. Once energized, the implement pilot shutoff
solenoid will not be disabled with the park brake switch.

NOTE: If the pattern switch is installed, a pattern (1 or 2) must be chosen before the
park brake can be released.

The work tool hydraulic system can be disabled independently of the travel system by
depressing the optional hydraulic lockout switch or by opening the operator's compartment
door. The implement pilot shutoff solenoid remains energized as long as the hydraulic lockout
switch and the door switch remain closed to ground. Opening either of the switches causes the
ECM to disable the solenoids. The implement pilot shutoff solenoid is re-energized when the
hydraulic lockout switch and the door switch are closed to ground.
SERV1833 - 49 - Text Reference
03/07

HYDROSTATIC DRIVE SYSTEM

Left Motor Right Motor

Speed Sensor Speed Sensor
Left Right
Motor Motor
Engine Speed Sensor
Throttle Lever Position Sensor
Parking Parking Machine
Brake Brake ECM
Joystick Position Signals
Park Brake Switch
Pump Control Pump Control Creeper Control Switch
Solenoid Valves Solenoid Valves
(Left Motor) (Right Motor)

Work Tool Charge Demand

Engine Pilot ON/OFF
Pump Pump Fan Motor
Solenoid

Hydrostatic
Drive Pump

Hydraulic
Oil Filter

47

POWER TRAIN

The hydrostatic drive system is now electronically controlled by the Machine ECM through
four pump control solenoids. The joysticks send a signal to the ECM when moved by the
operator. The ECM sends corresponding signals to the pump control solenoid valves, which
control pump output flow to the travel motors.

Each motor includes a speed sensor for the feedback signal to Machine ECM. The ECM also
receives input from the engine speed sensor and the throttle lever position sensor to control the
underspeed function. The speed sensing valve has been eliminated.

The travel pilot solenoid and park brake solenoid have been eliminated and replaced by the
travel pilot ON/OFF solenoid valve located on the hydrostatic pump. The park brake switch
sends a signal to the ECM to control the park brake function.

The creeper switch sends a signal to the Machine ECM, which allows the operator to select a
maximum machine travel speed at full joystick movement.

A two-speed valve is also located on the pump if the machine is equipped with the optional
two-speed motors.
SERV1833 - 50 - Text Reference
03/07

1 3
8 6
4

11

7 12

9 5
10

48

This illustration shows the left side of the hydrostatic pump. From the left side of the pump the
following components are visible:

- Left motor reverse pump solenoid (1)

- Left motor servo pressure port (2)
- Right motor servo pressure port (3)
- Right motor reverse pump solenoid (4)
- Right reverse crossover relief and makeup valve (5)
- Pilot ON/OFF solenoid valve (6)
- Charge oil to implement pilot shutoff valve (7)
- Charge relief valve (8)
- Case drain port (9)
- Left reverse crossover relief and makeup valve (10)
- Left forward crossover relief and makeup valve (11)
- Right forward crossover relief and makeup valve (12)
SERV1833 - 51 - Text Reference
03/07

3 5 6
2 4
1
7
8

15 9
10

14

13

11

12

49

This illustration shows the right side of the hydrostatic pump. From the right side of the pump
the following components are visible:

- Right forward pump solenoid (1)

- Right forward drive loop port (MC) (2)

- Brake supply port (3)

- Left forward drive loop port (MB) (4)

- Charge pressure tap (5)

- Left forward pump solenoid (6)

- Left motor servo pressure port (7)

- Right motor servo pressure port (8)

- Case drain port (9)

SERV1833 - 52 - Text Reference
03/07

- Charge oil inlet port (10)

- Left forward travel drive loop port (11)

- Left reverse travel drive loop port (12)

- Right reverse travel drive loop port (13)

- Right forward travel drive loop port (14)

- Case drain port (15)

SERV1833 - 53 - Text Reference
03/07

50

The travel drive motors are radial piston motors with the same type of design as the "B" Series
machines. The brakes are spring engaged and hydraulically released.

Each hydrostatic drive motor contains a flushing valve. The flushing valve maintains a
minimum system pressure as it drains some oil from the low pressure side of the drive loop.
The pump crossover relief valves helps supply the makeup oil that the flushing valve drains.

As the oil flows to the case drain, heat and any contamination is purged from the drive loop.

The "C" Series travel motors each contain a speed sensor (arrows) that send a speed signal to
the Machine ECM indicating indicating motor speed and direction.speed.

A two-speed travel system is optional on all machines. The two-speed travel motor contains
additional spools and passages which forces the motor to spin faster for the same flow rate rate
from the pump..

A two-speed solenoid is mounted below the hydrostatic drive pump. the hydrostatic drive
pump. The two-speed solenoid valve is used to shift the travel motor control spool.
SERV1833 - 54 - Text Reference
03/07

HYDROSTATIC DRIVE SYSTEM

NEUTRAL
To Pilot Shutoff From Manual
Solenoid Lowering Valve
From Pilot Shutoff
Cooler
Solenoid

From Work Tool

To / From Valve Group
Travel Motor Travel Motor Work Tool
Flushing Flushing Coupler Valve
Return Hydraulic System
Valve Valve Filter
Manifold

Demand Fan Motor

Park Pilot On/Off Park

Brake Solenoid Brake

Left Pump Right Pump

Solenoid Valve Solenoid Valve
To Work Tool
Hydrostatic Valve Group
Drive Pump

ATAAC
Actuator Fan Motor
Piston
M

Actuator Crossover
Piston Relief Valves Work Tool Charge ATAAC
Pump Pump Pump

Crossover Charge
Relief Valves Relief Valve

51

This illustration shows the "C" Series machines hydrostatic drive hydraulic system in the
NEUTRAL position.

The charge pump sends oil through the demand fan motor and hydraulic oil filter to the charge
pump relief valve, the crossover relief and makeup valves, the park brake solenoid valve, the
two-speed solenoid valve (if equipped), and the implement pilot shutoff valve.

When the engine is started, the park brake solenoid is de-energized. The park brake solenoid
directs oil to drain and the park brakes are engaged by spring force. When the operator
depresses the park brake switch, a signal is sent to the Machine ECM. The ECM energizes the
park brake solenoid. The park brake solenoid valve directs oil to the park brake piston and the
pump control solenoid valves. The charge pump oil acts against spring force to release the park
brakes.

The pump solenoid valves control charge oil to the actuator pistons upon command of the
Machine ECM. The actuator pistons control the swashplates. The angle of the swashplates
control the amount of oil and the direction of oil flow from the pump to the motors.
SERV1833 - 55 - Text Reference
03/07

In NEUTRAL, the speed and direction control lever is centered. No signal is sent from the
control lever to the Machine ECM. The pump control valves are held in the center position by
spring force and no pressure oil is directed to the actuator pistons. With no signal pressure oil
to either end of the actuator pistons, the pistons stay in the centered or neutral position.

The centering springs for the actuator pistons hold the swashplates at zero angle. With the
swashplates in this position, the hydrostatic drive pump group does not produce oil flow.
Without output from the hydrostatic drive pump group to turn the drive motors, the machine
does not move.

The crossover relief and makeup valves protect the system by either maintaining a minimum
drive loop pressure or reducing pressure spikes in the drive loops. At machine start-up, the
makeup valves open to direct charge oil to both sides of the pump and motor. The oil in both
lines to the drive motors are approximately at charge pressure.

The main purpose of the travel motor flushing valve is to drain some oil from the low pressure
side of the drive loop to case drain, which purges heat and contamination from the drive loop.
The relief valve in the flushing valve also controls the minimum pressure in the low pressure
side drive loop when the machine moves.
SERV1833 - 56 - Text Reference
03/07

HYDROSTATIC DRIVE SYSTEM

FORWARD

To Pilot Shutoff From Manual

Solenoid Lowering Valve
From Pilot Shutoff
Cooler
Solenoid

From Work Tool

To / From Valve Group
Travel Motor Travel Motor Work Tool
Flushing Flushing Coupler Valve
Return Hydraulic System
Valve Valve Filter
Manifold

Demand Fan Motor

Park Pilot On/Off Park

Brake Solenoid Brake

Left Pump Right Pump

Solenoid Valve Solenoid Valve
To Work Tool
Hydrostatic Valve Group
Drive Pump

FWD
ATAAC
Actuator Fan Motor
Piston
M

Actuator Crossover
Piston Relief Valves Work Tool Charge ATAAC
Pump Pump Pump

Crossover Charge
Relief Valves Relief Valve

52

This illustration shows the conditions that are present when the speed and direction lever is
moved to the FORWARD position.

As the speed and direction lever is moved forward, a signal is sent to the Machine ECM. The
ECM sends corresponding signals to the right and left pump forward solenoids. The pump
solenoid valves direct signal pressure to the the actuator pistons.

The Machine ECM receives feedback signals from the travel motor speeds sensors. The ECM
processes the speed signals and sends the appropriate signals to the right and left pump forward
solenoids to precisely control machine ground speed.

For FORWARD, the oil flows to the end of both actuator pistons. The magnitude of the
Machine ECM signal to the right and left pump forward solenoids determines the signal
pressure oil at the actuator piston and how far the actuator pistons move.
SERV1833 - 57 - Text Reference
03/07

The signal pressure oil at the actuator pistons moves the swashplates to the forward position.
As the swashplates move, pump output flow increases and is sent to the drive motors. The oil
from the pump also flows to the top of the flushing valve and moves it down. With the
flushing valve moved, oil from the low pressure side of the drive motors flows through the
flushing valve and the relief valve back to the return manifold.

With no restrictions in the drive motor loop, the oil flow causes the drive motors to rotate, and
the machine moves FORWARD.
SERV1833 - 58 - Text Reference
03/07

TWO-SPEED HYDROSTATIC DRIVE SYSTEM

RABBIT MODE

Two-speed Valve
To Drain Manifold
To Pilot
Shutoff Solenoid

Travel Motor

Flushing
Flushing
Two-speed Valve Two-speed
Valve
Selector Spool Selector Spool
Park Brake Travel Motor Park Brake

Left Pump
Solenoid Valve Right Pump
Solenoid Valve

Crossover
Relief Valve
Crossover
Actuator Pilot On/Off Relief Valve Actuator
Piston Solenoid Piston
M M

Crossover Crossover
Relief Valve Relief Valve

Charge Pressure Hydrostatic Drive Pump

Relief Valve
From Charge Pump

53

This illustration shows the "C" Series machines hydrostatic drive pump and motors with the
two-speed option in the Forward/Turtle Mode position.

The two-speed solenoid valve is used to direct charge oil to shift the two-speed selector spool,
which controls oil flow from the hydrostatic pump to half of the travel motor pistons.

NOTE: The schematic shows two motor symbols in each motor. Each motor symbol
represents half of the pistons in the motor.

The travel motor is a radial-piston type motor. Two sets of passages direct flow to and from the
hydrostatic pump to the motor pistons. On the "C" Series Skid Steer Loaders half of the oil
flow passages are blocked.

In Turtle Mode, pump operation is identical to the standard hydrostatic drive system and the
two-speed travel motor operates the same as the standard travel motor. The two-speed solenoid
is de-energized and oil flows past the two-speed selector spool.
SERV1833 - 59 - Text Reference
03/07

To activate Rabbit Mode, the operator must select Rabbit Mode on the multifunction switch
located on the left overhead console and then press the left joystick trigger switch on the front
of the speed and direction lever. The multifunction switch and trigger switch signal the
Machine ECM, which energizes the two-speed solenoid.

The two-speed solenoid valve directs charge oil to shift the two-speed selector spool. The
two-speed selector spool blocks oil flow from the hydrostatic pump to half of the travel motor
oil flow passages.. The travel motor speed increases due to the decreased displacement of the
travel motor. The charge oil keeps the pistons seated, avoiding wear.

The default state for the two-speed travel system is Turtle Mode. The Machine ECM returns
the machine to Turtle Mode whenever the machine is turned off.
SERV1833 - 60 - Text Reference
03/07

ELECTRONIC CONTROL SYSTEM

ENGINE UNDERSPEED FUNCTION

Left Forward
Engine Speed Pump Solenoid
Left Reverse
Sensor
Pump Solenoid

Throttle Position Machine ECM Right Forward Right Reverse

Sensor
Pump Solenoid Pump Solenoid

54

This illustration shows the components used to control the machine underspeed function.

The underspeed function of the Machine ECM senses the increase and decrease in the engine
speed caused by the total load on the machine. The underspeed function distributes the
available engine power between the requirements of the hydrostatic drive system and
implement hydraulic system. When the underspeed function is needed, the Machine ECM will
automatically signal the appropriate pump control solenoids to decrease or increase the
hydrostatic pump displacement.

The Machine ECM uses the engine speed sensor and the throttle lever position sensor to
perform the underspeed function. The Machine ECM determines desired engine speed by
reading the signal from the throttle position sensor. The ECM determines actual engine speed
by reading the signal from the engine speed sensor.

If the engine speed is too low, the Machine ECM decreases the the hydrostatic pump
displacement as necessary to reduce the power demand and keep the engine from stalling.
SERV1833 - 61 - Text Reference
03/07

When a travel mode is selected and the engine speed is increased, the Machine ECM increases
the signal to the pump control solenoid valves. This action results in higher speed once the
speed and direction lever is moved.

When the machine decelerates, the travel motor speed sensors send a signal to the ECM
indicating a decrease in ground speed. The ECM sends a corresponding signal to de-energize
the pump control solenoids. Also, the charge pump sends less oil flow to the pump control
solenoid valves. With a decreased Machine ECM signal to the pump control solenoid valves
and less charge pump oil flow to the solenoid valves, the hydrostatic pump begins to destroke.
This action also prevents engine lug.
SERV1833 - 62 - Text Reference
03/07

9 3 2

7
4

55
10 1

5 6 5

1 8

4 7 10

10 56

5 5
6

Two types of undercarriages are available on the "C" Series Multi-Terrain Loaders. The top
illustration shows the Dual Level Suspension (DLS). The bottom illustration shows the Single
Level Suspension (SLS).

The dual level suspension uses flexible torsional axles, which allow each undercarriage roller
assembly to flex independently for smoother travel.

Each undercarriage assembly consists of a hydrostatic axial piston motor (1) which has the
drive sprocket assembly (2) attached to it. The sprocket assembly can be removed as a unit to
service the roller sleeves (3).
SERV1833 - 63 - Text Reference
03/07

The hydrostatic motor requires an oil change after the first 250 service hours and every
subsequent 1000 service hours.

The roller frame assembly (4) supports the front and rear idler wheels (5) and the
bogie wheels (6).

The tensioner (7) allows adjustment of the track tension. As the hydrostatic piston motor
support structure (drive table) (8) rotates, the drive sprocket group rotates engaging the triple
row of lugs on the track (9).

An extra (third) row of drive lugs and an extra (third) row of rollers has been added to the
sprocket assembly on the "C" Series machines. Also, a extra (fourth) row of bogie wheels has
been added to the "C" Series machines

Grease fittings (10) located at the front and rear of the undercarriage were installed on the 287B
but not on the 267B or the 277B Multi-Terrain Loaders.

Note: Grease fittings are located at the front and at the rear of both the DLS and SLS
undercarriage. Not all grease fittings are visible in the illustrations.

The undercarriage area is more open which aids cleaning and does not retain dirt and debris

Other service changes from the "B" Series to the "C" Series machines include the addition of
metal face seals.
SERV1833 - 64 - Text Reference
03/07

2 3

57

The fan (1) and fan motor (2) are located in the rear compartment. The fan provides cooling air
for the radiator and hydraulic oil cooler. The fan motor receives oil flow from the charge pump
to drive the fan.

The "C" Series machines are equipped with a demand fan, which is standard on all machines.
Fan speed is controlled by the Machine ECM through a solenoid (3) on the fan motor. The
demand fan solenoid regulates the amount of oil flow supplied to the fan motor and also acts as
a relief valve for the fan circuit at high engine speeds.

The Machine ECM controls the fan speed based on signals from the coolant temperature sensor
and the hydraulic oil temperature sensor.

The hydraulic oil sampling port (4) is located on the fan motor.
SERV1833 - 65 - Text Reference
03/07

DEMAND FAN CIRCUIT

To Work MAXIMUM FAN SPEED
Tool Coupler

S O S Tap

To Hydrostatic
Demand Drive Pump
Fan Motor
Charge Hydraulic Oil
Pump Machine Temperature Sensor
ECM
Coolant
Temperature Sensor

Demand Fan
Solenoid

58

Oil from the charge pump flows to the demand fan motor. The demand fan solenoid regulates
the amount of oil flow supplied to the fan motor and also acts as a relief valve for the fan
circuit at high engine speeds. Oil from the fan motor flows through the hydraulic oil filter to
the hydrostatic drive pump.

This schematic shows the fan solenoid de-energized and the fan in the FULL SPEED condition.

The Machine ECM will energize the fan solenoid to decrease fan speed based on signals from
the hydraulic oil temperature sensor and coolant temperature sensor.
SERV1833 - 66 - Text Reference
03/07

WORK TOOL HYDRAULIC SYSTEM

Diverter
Valve

Ride Work Tool

Control Lift Tilt Auxiliary Control Valve

Lift Pilot Aux Pilot

Solenoids Tilt Pilot Solenoids
Solenoids
Pilot Supply
Solenoid
Continuous Flow Switch
Auxiliary Hydraulic Pressure Release Switch
Machine Hydraulic Lockout Switch
ECM Ride Control Switch
Auxiliary 1 Switch
Joystick Position Signals and Switches

Hydrostatic Work Tool Charge ATAAC Demand ATAAC

Engine
Drive Pump Pump Pump Pump Fan Motor Fan Motor

Hydraulic
Oil Filter

59

WORK TOOL HYDRAULIC SYSTEM

The work tool hydraulic system is now electronically controlled by the Machine ECM through
the lift, tilt, and auxiliary solenoid valves. The joysticks send a signal to the ECM when moved
by the operator. The ECM sends corresponding signals to the solenoid valves, which control
the position of the lift, tilt, and auxiliary directional spools.

The work tool control valve internal hydraulic components are very similar to the "B" Series
machines.

A pilot shutoff solenoid valve replaces the work tool pilot solenoid.

The electronically controlled auxiliary function is the same as the "B" Series machine.

The ride control system is new to the "C" Series machines and operates similar to Caterpillar
wheel loaders.

The work tool self level option is the same as the "B" Series machines.

The XPS High Flow Hydraulic System is now optional on all "C" Series machines.
SERV1833 - 67 - Text Reference
03/07

60

2
61

The hydraulic tank includes a new breather (1) at the top of tank that is serviceable. The tank
will have a hydraulic oil level sight glass (2) on the side of tank that is more visible from the
right side of the machine.
SERV1833 - 68 - Text Reference
03/07

4
1

2 3

62

The radiator (1) and hydraulic oil cooler (2) are more accessible in the "C" Series machines
because the grill raises to a higher angle than the "B" Series machines.

An oil fill access (3) has been added to the oil cooler to allow hydraulic oil to be added to the
hydraulic system without having to raise the cab to access the hydraulic tank.

Also visible in this illustration is the radiator cap (4).

SERV1833 - 69 - Text Reference
03/07

1
3
2

63

64

The top illustration shows the standard work tool gear pump (1) for a machine without the High
Flow option. Also shown is the ATAAC pump (2) mounted to the charge pump (3).

The bottom illustration shows the variable displacement piston pump (4) for machines with the
High Flow option. The pumps have not changed but the pump control valve (5) on the High
Flow machines has been relocated from the side of the pump to the bottom of the pump.
SERV1833 - 70 - Text Reference
03/07

1
2
65

1
2

66

The work tool control valve (1) and diverter (self-leveling) valve (2) are located above the right
frame rail. The self-leveling option has the same functionality as the "B" Series machines.

A removable panel (not visible) allows easy access to the components located below the right
side of the cab.

The diverter valve can be easily accessed to allow installation in the field.
SERV1833 - 71 - Text Reference
03/07

12 1
1

2 13 2
4
3
5
3
6
7

4 8
8 5 9
9 6 10
10 7 11
13
11

14 14

67

These illustrations show the work tool control valve on a High Flow machine in different
positions. The top left illustration shows the work tool control valve in the same position as it
would be installed above the right frame rail in the machine.

The components visible are:

- Auxiliary line relief valve (1) - Auxiliary return solenoid valve (8)

- Tilt head end line relief valve (2) - Tilt back solenoid valve (9)

- Lift line relief valve (3) - Lower solenoid valve (10)

- Auxiliary supply solenoid valve (4) - C- solenoid valve (11)

- Tilt forward solenoid valve (5) - Pilot pressure port (12)

- Raise solenoid valve (6) - Tilt rod end line relief valve (13)

- C+ solenoid valve (7) - Load sense relief valve (14)

SERV1833 - 72 - Text Reference
03/07

1 68

3
69

Travel at high speeds over rough terrain causes work tool movement. The optional Ride
Control System acts as a shock absorber by absorbing work tool forces, which stabilize the
machine.

The new ride control valve (1) is located next to the diverter valve (2) above the right frame
rail. The ride control accumulator (3) is located near the bottom of the right frame rail.

The ride control valve contains two solenoids (4) and a double check valve (not visible).

The Ride Control System is controlled by the Machine ECM. The Machine ECM receives a
signal from the ride control switch to operate the ride control system. The ECM sends a signal
to the ride control relay, which energizes the ride control solenoids.
SERV1833 - 73 - Text Reference
03/07

RIDE CONTROL SYSTEM

ON
Lift
Cylinders

To / From
Diverter Valve

To / From
Solenoid Work Tool
Solenoid Lift Valve
Double
Check
Ride Control Valve
Accumulator Ride
Machine Ride Control
Control
ECM Switch
Relay

Ride Control Valve

70

This illustration shows a hydraulic schematic of the Ride Control System. With the Ride
Control System ON and the lift control valve in HOLD, oil is blocked at both the rod and head
ends of the lift cylinders.

When the ride control switch is activated, a signal is sent to the Machine ECM. The ECM
sends a corresponding signal to the ride control relay. The ride control relay energizes the
solenoids and oil from the head end of the lift cylinders flows through one solenoid which
connects the head end of the lift cylinders to the ride control accumulator. Oil from head end of
the lift cylinders also moves the double check valve down to block oil from the head end of the
lift cylinders from flowing to the tank. Oil from the rod end of the lift cylinders is open to the
tank through the other solenoid.

With the Ride Control System OFF, the ride control solenoids are de-energized. Oil from the
rod end of the lift cylinders is blocked from flowing to the tank through the ride control valve.
Oil from the head end of the lift cylinders flows through an orifice so that the ride control
accumulator is charged.

If the oil pressure is too high in the rod end of the lift cylinders with Ride Control ON, the
double check valve moves up and the oil in the head end of the lift cylinders is directed to the
tank.
SERV1833 - 74 - Text Reference
03/07

71

3
1 72

The implement pilot shutoff valve (1) is located on the right frame rail to the rear of the right
travel motor. The pilot shutoff solenoid (2) blocks oil to the work tool control valve solenoids
when the hydraulic lockout switch in the cab is activated.

The pilot accumulator (3) provides tilt, dump, and work tool auxiliary lowering capabilities for
a limited time after the engine has been shut down.
SERV1833 - 75 - Text Reference
03/07

73

Cat ToughGuard™ hydraulic hoses are used on the "C" Series machines. ToughGuard™ hoses
provide abrasion resistance, which exceeds the capabilities of standard hydraulic hoses. The
ToughGuard™ hoses include a polyethylene exterior cover, which eliminates the need for
nylon, or plastic add-on protection in most applications.
SERV1833 - 76 - Text Reference
03/07

WORK TOOL HYDRAULIC SYSTEM

HOLD
Lift Tilt Auxiliary
Cylinders Cylinders Tools
Line Relief
Valves Line Relief
Line Relief Valve
Valve

Work Tool
Valve Group Raise Dump Aux
Solenoid Solenoid Solenoid
Valve Valve Valve

Diverter Valve
Main Relief
Ball Valve Valve
(Dead Engine Lower)

Ride Control
Accumulator
Lift Tilt Auxiliary
Control Control Control Valve
Valve Valve
Ride Control
Valve Lower Rack Back Aux
Solenoid Solenoid Solenoid
Valve Valve Valve
Pilot Supply
Solenoid

Cooler
Coupler Cylinders

Return
Manifold
Hydraulic System
Coupler Filter
Valve

Demand Fan Motor

Hydrostatic Drive Pump Group

Work Tool Charge ATAAC

Pump Pump Pump ATAAC Fan Motor

74

This illustration shows the work tool hydraulic system in the HOLD position.

The "C" Series machines are equipped with an open-center work tool hydraulic system the
same as the "B" Series machines. However, the lift, tilt, and auxiliary functions are now
electro-hydraulically controlled, the same as the auxiliary functions were on the "B" Series
machines.

The work tool hydraulic system consists of a tank, a fixed displacement pump, a control valve
group, two lift cylinders, two tilt cylinders, and an auxiliary work tool. The work tool control
valves are in parallel as to pump flow. The work tool hydraulic system shares a hydraulic tank,
an oil filter, and an oil cooler with the hydrostatic drive system.

The lift, tilt, and auxiliary valve spools are each controlled by two solenoid valves located in
the work tool control valve group. The hydrostatic drive system charge pump provides pilot oil
to the solenoid valves. The charge relief valve in the hydrostatic pump group limits the
maximum pilot system pressure.

An accumulator provides tilt, dump, and work tool auxiliary lowering capabilities for a limited
time after the engine has been shut down.
SERV1833 - 77 - Text Reference
03/07

The optional automatic level control uses a diverter valve to maintain the work tool in a level
position during the raising of the loader arms.

At machine start-up with the work tool control lever in HOLD, the charge pump sends oil
through the fan motor and the oil filter to the hydrostatic drive pump group.

From the hydrostatic drive pump group, charge oil is sent to the pilot shutoff valve solenoid
and to the lift, tilt, and auxiliary solenoids in the work tool control valve group. The energized
pilot shutoff valve solenoid enables pilot oil to be available at the work tool solenoid valves.
The pilot shutoff valve solenoid and the work tool solenoid valves are energized by the
Machine ECM.

When the auxiliary thumbswitch on the work tool joystick is activated or the work tool control
lever is moved from the HOLD position, a signal is sent to the Machine ECM. The Machine
ECM sends a corresponding signal to energize a solenoid, which directs pilot oil to the
appropriate control valve spool in the control valve group. The more the thumbswitch or work
tool control lever is moved, the higher the pilot oil flow that is directed to the work tool control
valve spool.

The amount of pilot oil to the work tool control valve group determines the distance the spool
in the control valve shifts and the amount of hydraulic oil directed to the cylinders from the
pump.

The tilt circuit is equipped with combination line relief and makeup valves for the rod and head
ends of the cylinder. The lift circuit is equipped with a line relief valve and a manual lowering
valve on the head end of the lift cylinder circuit.

The auxiliary circuit is equipped with a line relief valve for the two auxiliary lines.

With all the control valve group valves in HOLD (shown), the pump supply oil flows through
the center passage of each valve before returning to the tank. When in HOLD, a centering
spring keeps the control spool centered. Pump supply oil enters the supply passages, flows
around the control spool, and flows to the next valve. Supply oil also flows to the load check
valve.
SERV1833 - 78 - Text Reference
03/07

WORK TOOL HYDRAULIC SYSTEM

RAISE
Lift Tilt Auxiliary
Cylinders Cylinders Tools
Line Relief
Valves Line Relief
Line Relief Valve
Valve

Work Tool
Valve Group Raise Dump Aux
Solenoid Solenoid Solenoid
Valve Valve Valve

Diverter Valve
Main Relief
Ball Valve Valve
(Dead Engine Lower)

Ride Control
Accumulator
Lift Tilt Auxiliary
Control Control Control Valve
Valve Valve
Ride Control
Valve Lower Rack Back Aux
Solenoid Solenoid Solenoid
Valve Valve Valve
Pilot Supply
Solenoid

Cooler
Coupler Cylinders

Return
Manifold Hydraulic System
Coupler Filter
Valve

Demand Fan Motor

Hydrostatic Drive Pump Group

Work Tool Charge ATAAC

Pump Pump Pump ATAAC Fan Motor

75

When the operator moves the work tool control lever to the RAISE position, a signal is sent to
the Machine ECM. The Machine ECM sends a corresponding signal to energize the raise
solenoid valve, which directs pilot oil to the top of the lift valve spool in the control valve
group. The lift valve spool is shifted down by pilot oil which blocks the oil flow through the
center of the valve to the next valve.

The return oil from the rod end flows through an internal passage in the lift control valve spool.
The oil flowing through the internal passage is restricted creating pressure which is less than
system pressure.

After flowing through the internal passage the return oil can become supply oil for the tilt
control valve or auxiliary control.
SERV1833 - 79 - Text Reference
03/07

If the work tool control lever is only partially shifted, some pump supply oil is metered through
the center of the lift valve to the next circuit and then to the tank (unless one of the other
control valves is fully shifted).

If the lift circuit is stalled in either direction, no oil returns from the lift cylinders to become
supply oil for the tilt circuit. If the lift control spool is fully shifted, there will also be no oil
metered to the tilt circuit. The tilt circuit will not function until the pilot valve for the lift
circuit is moved from the fully shifted position.

NOTE: Supply oil to the tilt and auxiliary circuits are shown in pink and red stripes to
reflect that the lift control valve is of a series flow design.
SERV1833 - 80 - Text Reference
03/07

HIGH FLOW HYDRAULIC SYSTEM

HOLD Tilt
Cylinders
Work Auxiliary
Tool Lift
Tools
Cylinders
Line Relief
Valves

Auxiliary
Solenoid
Valve A2
C+ Solenoid
Valve
Raise
Solenoid Dump
Load Sensing Aux Pump Valve Solenoid
Signal Rail Rail
Valve
Divert er Valve

Flow
Work Control Tilt
Ride Cont rol
Compensator Tool Orifice Aux.
Valve Lift
C- Solenoid Lower Rack Back Auxiliary
Valve Solenoid Solenoid Solenoid
Valve Valve Valve A1

Pilot Shut off

Solenoid

Cooler

Coupler
Cylinders
Return
Manifold Coupler
Valve

Demand Fan Motor

Hydraulic System
Filter

Hydrostatic Drive Pump Group

Work Tool
Pump
Charge ATAAC
Pump Pump ATAAC Fan Motor

76

This illustration shows the optional High Flow XPS Hydraulic System.

The High Flow XPS system features a load sensing, pressure compensated, variable
displacement piston pump and closed-center control valves used in a Proportional Priority
Pressure Compensated (PPPC) hydraulic system. The PPPC hydraulic system divides the oil
flow between each operating circuit in the system. The amount of oil directed to a particular
circuit is proportional to the position of the compensator control spool, which is controlled by
the load sensing signal rail.

Because the valves are pressure compensated, cylinder speeds will not change as the load varies
as long as the pump can meet system flow needs. When the flow demands of the system
exceed the total flow available from the pump, the flow is divided proportionally between all
activated circuits; however, the work tools will all move slower due to the reduced amount of
flow available.

The "A1" solenoid and "A2" solenoid provide pilot oil to shift the control spool for the
auxiliary and high flow functions. These solenoids are proportionally controlled by the
Machine ECM.
SERV1833 - 81 - Text Reference
03/07

The "C+" solenoid and "C-" solenoid provide pilot oil to shift the control spool for suppling oil
to the control flow lines on the work tool lift arm. The "C+" and "C-" solenoids are ON/OFF
and controlled by switches on the work tool joystick.

This illustration shows a control valve with only the "High Flow" A1 circuit activated. The
high flow circuit functions similar to the "standard flow" circuit, except that the Machine ECM
directs more current to the A1 solenoid valve, allowing the auxiliary control spool to shift
farther. When the thumbswitch is in the High Flow mode (maximum UP or DOWN position),
higher current is sent to the auxiliary solenoid. This will allow more hydraulic oil flow to the
auxiliary hydraulic circuit.

A dual stage load sensing relief valve is used to maintain system pressure. The system pressure
is increased during high flow operation through the "A1" or "A2" solenoid.

When only the high flow circuit is active, the Machine ECM will energize the solenoid for the
dual stage load sensing relief valve. The load sensing relief valve will limit the maximum
pressure to the higher setting.

NOTE: Although the outer two envelopes on each end of the auxiliary/high flow spool
are identical on the schematic, more flow is allowed through the outermost envelopes.
SERV1833 - 82 - Text Reference
03/07

77

CONCLUSION

This presentation has provided information on the "C" Series Skid Steer Loaders and Multi-
Terrain Loaders. Key service features, new components, and component locations were
identified and discussed.

This presentation supports the service manual. For service repairs, adjustments, and
maintenance, always refer to the Operation and Maintenance Manual, Service Manuals, and
other related service publications.
SERV1821 - 83 - Visual List
12/06

VISUAL LIST
1. Model view 41. Machine ECM inputs and outputs
2. Key new features 42. Machine status screen
3. Similarities and differences 43. Machine configuration screen
4. Operator's station 44. Component calibration using ET
5. Right side of cab 45. Cat ET Winflash program
6. Air conditioning ducting 46. Machine ECM inputs and outputs -
7. Mechanical suspension seat interlock strategy
8. Armrests in DOWN position 47. Hydrostatic drive system
9. Joystick adjustment lever 48. Left side of hydrostatic pump
10. Right joystick adjustment lever 49. Right side of hydrostatic pump
11. Auxiliary functions - standard 50. Travel drive motors speed sensor
configuration 51 Hydrostatic drive system - NEUTRAL
12. Auxiliary functions - high flow 52. Hydrostatic drive system - FORWARD
configuration 53. Hydrostatic drive system - RABBIT MODE
13. Control lever patterns 54. Electronic control system - engine
14. Fuse panel underspeed function
15. Cab fresh air filter 55. Dual Level Suspension (DLS)
16. Lifting hooks 56. Single Level Suspension (SLS)
17. Governor control lever 57. Fan and fan motor
18. Throttle position sensor 58. Demand fan circuit - MAXIMUM FAN
19. Throttle position sensor SPEED
20. Windshield washer reservoir 59. Work tool hydraulic system
21. Dead engine lower knob 60. Hydraulic tank breather
22. Door unlocking mechanism 61. Hydraulic oil level sight glass
23. Door removing procedure decal 62. Radiator and hydraulic oil cooler
24. Left overhead console 63. Work tool gear pump
25. Left overhead display 64. Variable displacement piston pump
26. Warning indicators illuminated 65. Work tool control valve and diverter valve
27. Heating and air conditioning controls 66. Work tool control valve and diverter valve
28. Creeper control switch 67. Work tool control valve positions
29. Right overhead display panel 68. Ride control valve
30. Digital display window 69. Ride control accumulator
31. Operator modes 70. Ride control system - ON
32. Display panel in service mode 71. Implement pilot shutoff valve
33. Select key and scroll up key 72. Pilot accumulator valve
34. 3044C engine 73. ToughGuard™ hydraulic hoses
35. Oil filter 74. Work tool hydraulic system - HOLD
36. Air to air aftercooler (ATAAC) 75. Work tool hydraulic system - RAISE
37. Panel opening for cleaning 76. High flow hydraulic system - HOLD
38. Glow plug indicator 77. Conclusion
39. Electrical system
40. Machine ECM
SERV1833 - 84 - Text Reference
03/07

HYDRAULIC SCHEMATIC COLOR CODE

Black - Mechanical connection. Seal Red - High pressure oil

Dark Gray - Cutaway section Red/White Stripes - 1st pressure reduction

Light Gray - Surface color Red Crosshatch - 2nd reduction in pressure

White - Atmosphere or Pink - 3rd reduction in pressure

Air (No pressure)

Purple - Pneumatic pressure Red/Pink Stripes - Secondary source oil pressure

Yellow - Moving or activated components Orange - Pilot, charge, or Torque Converter oil

Cat Yellow - (R estricted usage) Orange / White Stripes -

Identification of components Reduced pilot, charge, or TC oil pressure
within a moving group
Orange Crosshatch - 2nd reduction in
Brown - Lubricating oil pilot, charge, or TC oil pressure.

Green - Tank, sump, or return oil Blue - Trapped oil

Green / White Stripes -

Scavenge Oil or Hydraulic Void

HYDRAULIC SCHEMATIC COLOR CODE

This illustration identifies the meanings of the colors used in the hydraulic schematics and
cross-sectional views shown throughout this presentation.
 03/07
SERV1833

HYDRAULIC SCHEMATIC COLOR CODE

Black - Mechanical connection. Seal Red - High pressure oil

Dark Gray - Cutaway section Red/White Stripes - 1st pressure reduction

Light Gray - Surface color Red Crosshatch - 2nd reduction in pressure

White - Atmosphere or Pink - 3rd reduction in pressure

Air (No pressure)

Purple - Pneumatic pressure Red/Pink Stripes - Secondary source oil pressure

- 85 -

Yellow - Moving or activated components Orange - Pilot, charge, or Torque Converter oil

Cat Yellow - (R estricted usage) Orange / White Stripes -

Identification of components Reduced pilot, charge, or TC oil pressure
within a moving group
Orange Crosshatch - 2nd reduction in
Brown - Lubricating oil pilot, charge, or TC oil pressure.

Green - Tank, sump, or return oil Blue - Trapped oil

Green / White Stripes -

Scavenge Oil or Hydraulic Void
Handout No. 1
SERV1833 - 86 - Handout No. 2
03/07

Machine Walk-around Checklist

Directions: Use this sheet when performing a machine orientation lab exercise.

Place a check in the blank after locating each of the following controls:
Key start switch
Armrests
Governor lever
Accelerator pedal
Left joystick
Horn
Continuous flow switch
Auxiliary electrical controls (C1/C2, if equipped)
Auxiliary electrical control for pin "B" on loader arm (if equipped)
Two-speed switch
Multifunction switch
Right Joystick
Thumbswitch for A1/A2 auxiliary control
Secondary auxiliary control switches (C+/C-, if equipped)
Park brake switch
Creeper switch
Ride control switch (if equipped)
Pattern changer switch (if equipped)
HVAC controls (if equipped)
Dead engine lower knob

Place a check in the blank if the fluid level is acceptable:

Engine oil level
Hydraulic system oil level
Cooling system fluid level
Fuel level
SERV1833 - 87 - Handout No. 3
03/07

Machine Walk-around Checklist (continued)

Place a check in the blank after locating each of the following components:
Cab hold-down bolts
Fuse panel
Cab recirculation filter
Cab fresh air filter
Hydraulic oil filter
Engine oil fill cap
Engine oil filter
Fuel filter and water separator
Air filter indicator
Fuel tank and filler cap
Engine jump start receptacle
Battery
Machine ECM
Power relay modules
ATAAC housing and ATAAC motor (if equipped)
Hydraulic fill cap (Top Off)

Place a check in the blank after locating each of the following gauges and indicators:
Fuel level gauge
Service hour meter
Coolant temperature gauge (if equipped)
Hydraulic oil temperature gauge
Digital display window (if equipped)
SERV1833 - 88 - Handout No. 4
03/07

Left Overhead Display - Indicator Identification

List the name of each indicator shown above:

1) ____________________ 9) ____________________

2) ____________________ 10) ____________________

3) ____________________ 11) ____________________ (if equipped)

4) ____________________ 12) ____________________ (if equipped)

5) ____________________ (if equipped) 13) ____________________

6) ____________________ 14) ____________________ (if equipped)

7) ____________________ 15) ____________________ (if equipped)

8) ____________________ 16) ____________________ (if equipped)

SERV1833 - 89 - Handout No. 5
03/07

Optional Right Overhead Display - Mode Identification

Display each operator mode and service mode on the digital display window. Describe the
function of each mode.

Operator Modes

Mode 1: ______________________________________________________________

Mode 2: ______________________________________________________________

Mode 3: ______________________________________________________________

Service Modes

Mode 0: ______________________________________________________________

Mode 1: ______________________________________________________________

Mode 2: ______________________________________________________________

Mode 3: ______________________________________________________________

Mode 4: ______________________________________________________________

Mode 5: ______________________________________________________________

Mode 6: ______________________________________________________________

Mode 7: ______________________________________________________________
SERV1833 - 90 - Handout No. 6
03/07

Machine Systems Component Identification

Place a check in the blank after locating each of the following components:
ATAAC pump
ATAAC motor
Charge pump
Work tool pump
Hydrostatic drive pump
Hydrostatic drive pump control solenoids
Pilot ON/OFF solenoid valve
Two-speed solenoid valve (if equipped)
Travel motor speed sensors
Engine speed sensor
Throttle lever position sensor
Pilot shutoff valve solenoid and accumulator
Diverter valve
Work tool control valve
Load sense relief valve (High Flow System, if equipped)
Ride control valve (if equipped)
Ride control accumulator (if equipped)
Work tool coupler solenoid valve
Oil cooler
Hydraulic oil tank breather
Hydrostatic Drive System
03/07

Directions: Fill in the blanks next to the letters with the correct term.
SERV1833

B
To Pilot Shutoff From Manual
Solenoid Lowering Valve

C From Pilot Shutoff

Solenoid
C
From Work Tool
D To / From Valve Group
Travel Motor Travel Motor Work Tool
Coupler Valve
A Return Hydraulic System
E A Manifold Filter

F
Pilot On/Off D
B Solenoid B
G
- 91 -

M J To Work Tool
Valve Group
H K
E
I
M
I I
J
H
K
G F E

H L
L

M
Handout No. 7
Work Tool Hydraulic System
03/07

Directions: Fill in the blanks next to the letters with the correct term.
SERV1833

A
A C
B B

D L I D

E O M

F
J H E
G
N
H K G F
- 92 -

P
I

J
Return
Manifold
K
Hydraulic System
Filter
L

O
Hydrostatic Drive Pump Group

P
Q
Handout No. 8

Q
SERV1833 - 93 - Posttest
03/07

Posttest
1. The left and right joysticks:
A. are not adjustable
B. move only with the seat adjustment
C. are adjustable independently from the seat
D. are adjusted using a pushbutton below the joystick

2. Which of the following filters has been relocated on the "C" Series machines?
A. Engine air filter
B. Recirculation filter
C. Fresh air filter
D. None of the above

3. The optional digital display panel includes a digital display window and which of the
following gauges?
A. Hydraulic oil temperature gauge
B. Coolant temperature gauge
C. Engine oil pressure gauge
D. Both A and B

4. How many operator modes are available on the digital display?

A. 1
B. 2
C. 3
D. 4

5. The ATAAC fan is hydraulically driven by the:

A. ATAAC pump
B. hydrostatic drive pump
C. charge pump
D. work tool pump

6. Which of the following switches is an input to the Machine ECM for the interlock
control?
A. Seat switch
B. Armrest switch
C. Door switch
D. All of the above
SERV1833 - 94 - Posttest
03/07

7. Which of the following components has been eliminated from the hydrostatic drive
system on the "C" Series machines?
A. Motor flushing valve
B. Speed sensing valve
C. Charge relief valve
D. Crossover relief valve

8. The functions of the travel pilot valve solenoid and the pilot on/off solenoid are now
controlled by the:
A. pump control solenoid
B. travel pilot valve solenoid
C. pilot shutoff solenoid
D. park brake solenoid

9. The tilt and lift functions are controlled by the:

A. Machine ECM
B. work tool pilot valves
C. work tool relay
D. mechanical linkage

10. Which of the following components is new to the work tool hydraulic system?
A. Work tool pilot valves
B. Auxiliary solenoid valve
C. Pilot shutoff valve
D. Flow control orifice
SERV1833 - 95 - Posttest Answers
03/07

Posttest Answer Key

1. C
2. B
3. D
4. C
5. A
6. D
7. B
8. D
9. A
10. C