Jeep WG Grand Cherokee 2002 User manual

TABLE OF CONTENTS
1.0 INTRODUCTION .........................................................1
1.1 SYSTEM COVERAGE ...............................................1
1.2 SIX-STEP TROUBLESHOOTING PROCEDURE ..........................1
2.0 IDENTIFICATION OF SYSTEM .............................................1
3.0 SYSTEM DESCRIPTION AND FUNCTIONAL OPERATION ......................1
3.1 TEVES ABS SYSTEM DESCRIPTION ..................................1
3.1.1 PEDAL FEEL/VEHICLES CHARACTERISTICS ...................2
3.1.2 SYSTEM COMPONENTS.....................................2
3.1.3 ABS AND RED BRAKE WARNING INDICATOR...................2
3.1.4 CONTROLLER ANTILOCK BRAKE (CAB) .......................2
3.1.5 HYDRAULIC CONTROL UNIT .................................3
3.1.6 SENSORS .................................................3
3.2 ADJUSTABLE PEDALS SYSTEM DESCRIPTION .........................4
3.3 DIAGNOSTIC TROUBLE CODES ......................................4
3.3.1 ABS INITIALIZATION ........................................4
3.3.2 DIAGNOSTIC MODE ........................................4
3.3.3 INTERMITTENT DIAGNOSTIC TROUBLE CODES ................5
3.4 USING THE DRBIIIT.........................................5
3.5 DRBIIITERROR MESSAGES .................................5
3.5.1 DRBIIITDOES NOT POWER UP (BLANK SCREEN)...............5
3.5.2 DISPLAY IS NOT VISIBLE ....................................5
4.0 DISCLAIMERS, SAFETY, WARNINGS .......................................5
4.1 DISCLAIMERS......................................................5
4.2 SAFETY...........................................................6
4.2.1 TECHNICIAN SAFETY INFORMATION..........................6
4.2.2 VEHICLE PREPARATION FOR TESTING........................6
4.2.3 SERVICING SUB-ASSEMBLIES ...............................6
4.2.4 DRBIIITSAFETY INFORMATION...............................6
4.3 WARNING .........................................................7
4.3.1 VEHICLE DAMAGE WARNINGS ...............................7
4.3.2 ROAD TESTING A COMPLAINT VEHICLE.......................7
4.4 DIAGNOSIS................................................7
5.0 REQUIRED TOOLS AND EQUIPMENT ......................................7
6.0 GLOSSARY OF TERMS...................................................7
7.0 DIAGNOSTIC INFORMATION AND PROCEDURES ............................9
ADJUSTABLE PEDALS
PEDAL SENSOR OPEN/SHORTED TO BATTERY ............................10
PEDAL SENSOR SHORTED TO GROUND ..................................12
PEDAL SW STUCK FORWARD............................................13
PEDAL SW STUCK REARWARD ..........................................15
SYSTEM OVER VOLTAGE................................................17
SYSTEM UNDER VOLTAGE ..............................................18
*CAN’T ADJUST PEDALS ................................................19
*CAN’T SET/RECALL MEMORY POSITIONS.................................21
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TABLE OF CONTENTS - Continued
BRAKES (CAB)
BRAKE FLUID LEVEL SWITCH............................................22
CAB POWER FEED CIRCUIT .............................................25
CLUSTER FAULT .......................................................28
CONTROLLER FAILURE .................................................29
G-SWITCH NOT PROCESSABLE ..........................................31
LEFT FRONT SENSOR CIRCUIT FAILURE ..................................32
LEFT FRONT SENSOR SIGNAL FAILURE...................................34
LEFT REAR SENSOR CIRCUIT FAILURE ...................................37
LEFT REAR SENSOR SIGNAL FAILURE ....................................39
PCI BUS COMMUNICATION ..............................................42
PUMP MOTOR CIRCUIT NOT WORKING PROPERLY.........................43
RIGHT FRONT SENSOR CIRCUIT FAILURE.................................47
RIGHT FRONT SENSOR SIGNAL FAILURE..................................49
RIGHT REAR SENSOR CIRCUIT FAILURE ..................................52
RIGHT REAR SENSOR SIGNAL FAILURE...................................54
SYSTEM OVERVOLTAGE ................................................57
SYSTEM UNDERVOLTAGE ...............................................59
VERIFICATION TESTS
VERIFICATION TESTS...................................................61
8.0 COMPONENT LOCATIONS...............................................63
8.1 CONTROLLER ANTILOCK BRAKE ....................................63
8.2 DATA LINK CONNECTOR ...........................................63
8.2.1 DIAGNOSTIC JUNCTION PORT ..............................63
8.3 FUSES...........................................................64
8.4 TONE WHEELS....................................................64
8.5 WHEEL SPEED SENSORS ..........................................65
8.6 WHEEL SPEED SENSOR CONNECTORS..............................65
8.7 ADJUSTABLE PEDALS SWITCH......................................66
8.8 ADJUSTABLE PEDALS MODULE .....................................66
8.9 ADJUSTABLE PEDALS COMPONENTS................................66
9.0 CONNECTOR PINOUTS .................................................67
ADJUSTABLE PEDALS MODULE (EXCEPT BUILT-UP-EXPORT)
- GREEN 14 WAY .......................................................67
ADJUSTABLE PEDALS MOTOR/SENSOR ASSEMBLY
(EXCEPT BUILT-UP-EXPORT)-6WAY.....................................67
CONTROLLER ANTILOCK BRAKE - BLACK 24 WAY..........................67
LEFT FRONT WHEEL SPEED SENSOR - GRAY 2 WAY .......................68
LEFT REAR WHEEL SPEED SENSOR - GRAY 2 WAY ........................68
RIGHT FRONT WHEEL SPEED SENSOR - GRAY 2 WAY ......................68
RIGHT REAR WHEEL SPEED SENSOR - BLACK 2 WAY ......................68
10.0 SCHEMATIC DIAGRAMS.................................................69
10.1 WJ BODY TEVES MARK 20 .........................................69
10.2 ADJUSTABLE PEDALS SYSTEM .....................................70
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1.0 INTRODUCTION
The procedures contained in this manual include
all the specifications, instructions, and graphics
needed to diagnose Mark 20 Antilock Braking Sys-
tem (ABS) problems. The diagnostics in this man-
ual are based on the failure condition or symptom
being present at time of diagnosis.
Follow the recommendations below when choos-
ing your diagnostic path.
1. First make sure the DRBIIItis communicating
with the Controller Antilock Brake (CAB). If the
DRBIIItdisplays a ‘‘No Response’’condition, you
must diagnose that first.
2. Read DTC’s (diagnostic trouble codes) with the
DRBIIIt.
3. If no DTC’s are present, identify the customer
complaint.
4. Once the DTC or customer complaint is identi-
fied, locate the matching test in the Table of
Contents and begin to diagnose the symptom.
All component location views are in Section 8.0.
All connector pinouts are in Section 9.0. All sche-
matics are in Section 10.0.
An asterisk (*) placed before the symptom de-
scription indicated a customer complaint.
When repairs are required, refer to the appropri-
ate service manual for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added; carryover sys-
tems may be enhanced. READ THIS MANUAL
BEFORE TRYING TO DIAGNOSE A VEHICLE
CODE. It is recommended that you review the
entire manual to become familiar with all new and
changed diagnostic procedures.
After using this book, if you have any comments
or recommendations, please fill out the form at the
back of the book and mail it back to us.
1.1 SYSTEM COVERAGE
This diagnostic manual covers the Teves Mark 20
Antilock Braking System (ABS) and the Adjustable
Pedals system found on the Jeep Grand Cherokee.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the antilock brake system is done in
six basic steps:
•verification of complaint
•verification of any related symptoms
•symptom analysis
•problem isolation
•repair of isolated problem
•verification of proper operation
2.0 IDENTIFICATION OF
SYSTEM
Vehicles equipped with the Teves Mark 20 an-
tilock brake system can be identified by the pres-
ence of the hydraulic control unit located with the
controller antilock brake (CAB) under the hood
near the air cleaner housing.
Vehicles equipped with the Adjustable Pedals
system will have an Adjustable Pedals Switch
mounted below the instrument cluster and to the
right of the steering column.
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 TEVES ABS SYSTEM DESCRIPTION
A Controller Antilock Brake (CAB) module is
used to monitor wheel speeds and to modulate
(control) hydraulic pressure in each brake channel
to prevent wheel lock-up during braking. The CAB
also provides a vehicle speed signal (VSS) to the
powertrain control module.
During a non-ABS stop, the system functions as a
standard front/rear split configuration. The pri-
mary supplies brake fluid pressure to the front
brakes, and the secondary supplies the rear brakes.
A conventional combination/proportioning valve is
not used. This system uses the existing ABS sole-
noids to replace and perform the same functions
that the combination and proportioning valves do.
The CAB has a special software program called
Electronic Variable Brake Proportioning (EVBP),
that monitors the wheel speeds and when certain
criteria are met the software will enable the sole-
noids to perform the same brake fluid management
control as the combination/proportioning valves.
During an ABS stop, the system still uses the
front/rear hydraulic split; however, the brake sys-
tem pressure is further split into three control
channels. During ABS operation, the front wheels
are controlled independently and are on two sepa-
rate control channels. The rear wheels are con-
trolled together through one control channel. By
using separate control channels for each front
wheel, more steering control is maintained during
maximum braking.
During an antilock stop, ‘‘wheel lock-up’’ does not
necessarily mean that the wheel has locked, it
means only that the wheel is turning slower than
the vehicle speed. This is called ‘‘wheel slip’’ and is
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indicated as a percentage. 0% slip means that the
wheel is rolling free and 100% slip means that the
wheel is locked. The antilock system maintains an
average of approximately 20% wheel slip.
It is important to remember that the antilock
brake system does not shorten the vehicle stopping
distance under all driving conditions, but provides
improved control of the vehicle while stopping.
Vehicle stopping distance is still dependent on ve-
hicle speed, weight, tires, road surface, and other
factors.
3.1.1 PEDAL FEEL/VEHICLES
CHARACTERISTICS
There are several pedal feel/vehicle characteris-
tics that are considered normal for antilock braking
that may require further explanation.
When stopping conditions activate the antilock
brakes, the driver may feel some vibrations/
pulsations in the brake pedal and may hear the
solenoid valves clicking and the pump motor run-
ning. The vibrations/pulsations are caused by the
isolating, building and decaying of brake fluid pres-
sure within the brake lines. The ABS prevents
complete wheel lock-up, but some wheel slip is
required for the best braking performance. This slip
may result in some tire chirping, depending on the
road surface. The chirping should not be inter-
preted as total wheel lock-up. Total wheel lock-up
leaves black tire marks on dry pavement, antilock
braking may leave some light marks.
At the end of an ABS stop, theABS may function
all the way down to near 0 km/h (0 mph). There may
be a slight brake pedal drop anytime the ABS is
deactivated.
In case of braking on a bumpy surface, the ABS
module may detect wheel locking tendencies due to
wheel hop and cycle ABS. In that event the brake
pedal may pulsate with a perceived loss of deceler-
ation. ABS braking may also be activated at times
while on dry pavement with sand, gravel, or other
loose debris on the road.
It should be noted that the pulsating pedal feel
characteristic will not illuminate the brake warning
lamps or set a trouble code that is stored in the
Controller Antilock Brake (CAB). When investigat-
ing a hard pedal feel, inspect the sensor and tone
wheel teeth for chips/broken teeth, damaged sensor
pole tips, excessive runout of the tone wheel, or
excessive gap.
3.1.2 SYSTEM COMPONENTS
ANTILOCK BRAKE SYSTEM
•controller antilock brake (CAB)
•vacuum booster
•master cylinder (w/center valves)
•hydraulic control unit (HCU)
•valve block assembly: 6 valve solenoids (3 inlet
valves, 3 outlet valves)
4 accumulators
•brake fluid level switch (part of the fluid reser-
voir)
•pump/motor assembly:
1 motor
2 pumps
•4 wheel speed sensor/tone wheel assemblies
•ABS warning indicator
•fuses and wiring harness
•fluid reservoir (integral part of master cylinder
assembly)
3.1.3 ABS AND RED BRAKE WARNING
INDICATOR
The amber ABS warning indicator is located in
the instrument cluster. It is used to inform the
driver that the antilock function has been turned off
due to a system malfunction. On the WJ, the CAB
controls the lamp indirectly.
The CAB monitors its own functions. If the CAB
determines that theABS indicator should be on, the
CAB sends a message via the PCI BUS to the
instrument cluster and the cluster turns on the
indicator.
The instrument cluster sends a message over the
PCI BUS at regular intervals, if the CAB does not
respond the instrument cluster will illuminate the
ABS indicator.
The red brake warning indicator is located in the
instrument cluster. It can be activated by applica-
tion of the parking brake, a leak in the front or rear
wheel brake hydraulic circuit which causes the
master cylinder reservoir to be low on fluid, or by
turning the ignition switch to the start position.
The red brake warning indicator can also be turned
on if the brake fluid level switch circuit becomes
open or shorted to ground.
3.1.4 CONTROLLER ANTILOCK BRAKE
(CAB)
The antilock brake controller (CAB) is a
microprocessor-based device that monitors wheel
speeds and controls the antilock functions.
The primary functions of the CAB are:
•monitor wheel speeds
•detect wheel locking tendencies
•control fluid pressure modulations to the brakes
during antilock stop operation
•control the ABS warning indicator
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•monitor the system for proper operation
•provide communication to the DRBIIItwhile in
diagnostic mode
•store diagnostic information in non-volatile mem-
ory
The CAB continuously monitors the speed of each
wheel. When a wheel locking tendency is detected,
the CAB will command the appropriate HCU valve
to modulate brake fluid pressure to that wheel.
Brake pedal position is maintained during an an-
tilock stop by being a closed system with the use of
3 accumulators. The CAB continues to control pres-
sure in individual hydraulic circuits until a wheel
locking tendency is no longer present. The CAB
turns on the pump/motor during an antilock stop.
The antilock brake system is constantly moni-
tored by the CAB for the proper operation. If the
CAB detects a system malfunction, it can disable
the antilock system and activate the ABS warning
indicator. If the antilock function is disabled, the
system will revert to standard base brake system
operation.
The CAB inputs include the following:
•four wheel speed sensors
•brake lamp switch
•ignition switch
•battery voltage
•diagnostic communication (PCI BUS)
The CAB outputs include the following:
•six valve/solenoid drivers
•pump/motor actuation
•ABS warning indicator actuation
•red brake warning indicator actuation
•diagnostic communication (PCI BUS)
3.1.5 HYDRAULIC CONTROL UNIT
The hydraulic control unit (HCU) contains the
valve block assembly, four accumulators, and the
pump/motor assembly.
Valve Block Assembly: The valve block assem-
bly contains 6 valves with three inlet valves and
three outlet valves. The inlet valves are spring-
loaded in the open position and the outlet valves are
spring loaded in the closed position. During an
antilock stop, these valves are cycled to maintain
the proper slip ratio for each channel. The CAB
monitors wheel speeds. If the CAB detects a wheel
deceleration that is disproportionate to the other
wheels, it will close the inlet valve to that wheel.
This prevents any increase in fluid pressure. If the
wheel continues to decelerate disporportionately,
the CAB opens the outlet valve for that wheel to
release fluid pressure from that channel. The re-
leased fluid is routed to the accumulators. When the
wheel speed is no longer disproportionate to the
other wheels, the inlet valve will return to its
normally open position and the outlet valve will
return to the normally closed position.
Pump/Motor Assembly: The pump/motor as-
sembly provides the extra amount of fluid needed
during antilock braking. The pump is supplied fluid
that is released to the accumulators when the outlet
valve is opened during an antilock stop. The pump
is also used to drain the accumulator circuits after
the antilock stop is complete. The pump is operated
by an integral electric motor. This motor is con-
trolled by the CAB. The CAB turns on the motor
when an antilock stop is detected. The pump con-
tinues to run during the antilock stop and is turned
off approximately 3-5 seconds after the stop is
complete. The CAB monitors the pump/motor oper-
ation internally.
Accumulators: The accumulators provide tem-
porary fluid storage during an antilock stop and are
drained by the pump/motor.
3.1.6 SENSORS
Wheel Speed Sensors and Tone Wheels: One
wheel speed sensor (WSS) is located at each wheel
and sends a small digital signal to the control
module (CAB). The CAB sends 12 volts down to the
sensor. The sensor has an internal magneto resis-
tance bridge that alters the voltage and amperage
of the signal circuit. This voltage and amperage is
changed by magnetic induction when a toothed
sensor ring (tone wheel) passes by a stationary
magnetic sensor (wheel speed sensor). The CAB
measures the voltage and amperage of the digital
signals for each wheel.
The front wheel sensor is attached to a boss in the
steering knuckle. The tone wheel is an itegral part
of the front axle shaft. The rear speed sensor is
mounted in the caliper adapter plate (rear disc only)
and the rear tone wheel is an integral part of the
rear rotor hub. The wheel speed sensor air gap
is NOT adjustable. Because of internal cir-
cuitry, a resistance check of WJ wheel speed
sensors will not determine correct or incor-
rect function.
Correct antilock system operation is dependent
on wheel speed signals from the wheel speed sen-
sors. The vehicle’s wheels and tires should all be the
same size and type to generate accurate signals. In
addition, the tires should be inflated to the recom-
mended pressures for optimum system operation.
Variations in wheel and tire size or significant
variations in inflation pressure can produce inaccu-
rate wheel speed signals; however, the system will
continue to function when using the mini-spare.
When driven over rough road surfaces, the rear
wheel speed sensor signals may be erratic and
cause a false trouble code (drum brakes only).
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Brake Warning Indicator Switch: The brake
warning indicator switch is a fluid level sending
switch. The CAB sends out a 12 volt signal to the
switch. The switch has a 1,000 ohm resistor inside
of it. This resistor is used for diagnostic purposes.
Normal voltage is about 2.3 volts. If the switch is
disconnected the resistor will be pulled out of the
circuit and the CAB will sense voltage at about 5
volts. If the fluid level becomes too low or the circuit
is shorted to ground, the voltage will be about 0
volts. Any fault condition will illuminate the red
brake warning indicator and the specific fault can
be read on the DRBIIIt.
3.2 ADJUSTABLE PEDALS SYSTEM
DESCRIPTION
GENERAL
TheAdjustable Pedals System (APS) is designed to
enable the fore and aft repositioning of the brake and
accelerator pedals. This results in improved ergo-
nomics in relation to the steering wheel for taller and
shorter drivers. Being able to adjust the pedal posi-
tions also allows the driver to set steering wheel tilt
and seat position to the most comfortable position.
The position of the brake and accelerator pedals can
be adjusted without compromising safety or comfort
in actuating the pedals. Repositioning the pedals
does not change the effort required for actuation.
Change of pedal position is accomplished by
means of a motor driven screw. Operating the
adjustable pedal switch activates the pedal drive
motor. The pedal drive motor turns a screw that
changes the position of the brake and accelerator
pedals. The pedal can be moved rearward (closer to
the driver) or forward (away from driver). The
brake pedal is moved on its activating lever to a
position where the driver feels most comfortable.
The accelerator pedal is moved at the same time
and the same distance as the brake pedal. The
accelerator pedal adjustment screw is turned by a
flexible shaft slaved off the brake adjustment screw.
Neither the pedal drive motor nor drive mecha-
nism are subject to the mechanical stress of brake
or accelerator application.
SYSTEM FEATURES
•Range of Adjustment
The pedals may be adjusted up to 3 in. (75 mm)
•Pedal Adjustment Speed
0.5 in./sec (12.5 mm/sec)
•Pedal Adjustment Inhibitors
Pedal adjustment is inhibited when the vehicle is
in reverse or when cruise control is activated.
•Memory
An optional memory feature is available. This
allows storing of one or two preferred pedal
positions in the Adjustable Pedal Module (APM).
A preferred position can be stored and recalled
using the door-mounted switches.
The door-mounted switches activate the Driver
Door Module (DDM). The DDM instructs the
APM via the PCI bus to store the current pedal
position.
A stored pedal position can be recalled (but not
stored) using the Remote Keyless Entry (RKE).
•Adjustable Pedal Feedback Message
The Electronic Vehicle Information Center
(EVIC) will display a message when the APS is
disabled. ie: “Adjustable Pedal Disabled — Cruise
Control Engaged” or “Adjustable Pedal Disabled
— Vehicle in Reverse”.
•Damage Prevention
Foot pressure or debris can stall pedal adjust-
ment. In order to avoid damage to system compo-
nents during pedal adjustment, the APM will
monitor pedal position sensor voltage. If theAPM
does not detect expected voltage change within
1.5 seconds, it will cut power to the adjustable
pedal motor.
3.3 DIAGNOSTIC TROUBLE CODES
The vehicle electronic system modules may re-
port any of several diagnostic trouble codes (DTC)s.
The possible DTCs for the ABS and Adjustable
Pedals System are listed in the table of contents.
Diagnostic trouble codes are retained in memory
until erased using the DRB, or automatically erased
after 255 key cycles or 3,500 miles.
3.3.1 ABS INITIALIZATION
System initialization starts when the key is
turned to ‘‘run’’. At this point, the CAB performs a
complete self-check of all electrical components in
the antilock brake systems.
At 20 km/h (12 mph) a dynamic test may be
performed. If the brake lamp switch is activated the
test will be run at 40 km/h (24 mph) regardless of
the brake lamp switch state. This will momentarily
run the pump/motor. If during the dynamic test, the
driver has his/her foot on the brake pedal, he/she
may feel the test through brake pedal pulsations.
This is a normal condition.
If any component causes a diagnostic trouble code
during system initialization or dynamic check, the
CAB will illuminate the ABS warning lamp.
3.3.2 DIAGNOSTIC MODE
For a Mark 20 system to enter a diagnostic mode,
vehicle speed must be below 10 km/h (6 mph) and
no ABS condition present. If vehicle speed is not
below 10 km/h (6 mph), a ‘‘No Response’’ message
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could be displayed by the DRBIIIt. The following
are characteristics of diagnostic mode:
•The amber ABS warning indicator will blink
rapidly (about
1
⁄ 2 second on and
1
⁄ 2 second off). If
a hard trouble code is present, such as a CAB
Power Feed Circuit diagnostic trouble code, the
ABS warning indicator will be illuminated with-
out blinking until the diagnostic trouble code
condition is corrected.
•Antilock operation is disabled.
3.3.3 INTERMITTENT DIAGNOSTIC
TROUBLE CODES
If the malfunction is not present while perform-
ing a test procedure, the diagnostic procedures will
not locate the problem. In this case, the code can
only suggest an area to inspect. Check for the
following:
•mechanical interference with brake or accelera-
tor pedal
•loose or corroded conditions
•damaged components (sensors, tone wheels,
pedal drive cable)
•damaged wiring
•excessive axle shaft runout
•loose pedal mounting
•hydraulic system leaks
•regular brake system problems, non-ABS related
If no obvious problems are found, erase diagnostic
trouble codes and with the key on, wiggle the wire
harness and connectors. Recheck for codes periodi-
cally as you work through the system. This proce-
dure may uncover a difficult to locate malfunction.
3.4 USING THE DRBIIIT
Refer to the DRBIIItuser’s guide for instructions
and assistance with reading diagnostic trouble
codes, erasing diagnostic trouble codes and other
DRBIIItfunctions.
3.5 DRBIIITERROR MESSAGES
Under normal operation, the DRBIIItwill dis-
play one of only two error messages:
— User-Requested WARM Boot or User-
Requested COLD Boot
If the DRBIIItshould display any other error
message, record the entire display and call the
STAR Center for information and assistance. This
is a sample of such an error message display:
ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548
err: 0x1
User-Requested COLD Boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.5.1 DRBIIITDOES NOT POWER UP
(BLANK SCREEN)
If the LED’s do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage (data link
16-way connector cavity 16). A minimum of 11 volts
is required to adequately power the DRBIIIt. Also
check for a good ground at the DLC.
If all connections are proper between the
DRBIIItand the vehicle or other devices, and the
vehicle battery is fully charged, an inoperative
DRBIIItmay be the result of faulty cable or vehicle
wiring.
3.5.2 DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition.
4.0 DISCLAIMERS, SAFETY,
WARNINGS
4.1 DISCLAIMERS
All information, illustrations, and specifications
contained in this manual are based on the latest
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information available at the time of publication.
The right is reserved to make changes at any time
without notice.
4.2 SAFETY
4.2.1 TECHNICIAN SAFETY INFORMATION
WARNING: ENGINES PRODUCE CARBON
MONOXIDE THAT IS ODORLESS, CAUSES
SLOWER REACTION TIME, AND CAN LEAD
TO SERIOUS INJURY. WHEN THE ENGINE IS
OPERATING, KEEP SERVICE AREAS WELL
VENTILATED OR ATTACH THE VEHICLE
EXHAUST SYSTEM TO THE SHOP EXHAUST
REMOVAL SYSTEM.
Set the parking brake and block the wheels before
testing or repairing the vehicle. It is especially
important to block the wheels on front-wheel drive
vehicles; the parking brake does not hold the front
drive wheels.
When servicing a vehicle, always wear eye pro-
tection, and remove any metal jewelry such as
watchbands or bracelets that might make an inad-
vertent electrical contact.
When diagnosing an antilock brake or adjustable
pedals system problem, it is important to follow
approved procedures where applicable. These pro-
cedures can be found in the service manual. Follow-
ing these procedures is very important to the safety
of individuals diagnostic tests.
4.2.2 VEHICLE PREPARATION FOR
TESTING
Make sure the vehicle being tested has a fully
charged battery. If it does not, false diagnostic codes
or error messages may occur.
4.2.3 SERVICING SUB-ASSEMBLIES
Some components of the antilock brake or adjust-
able pedals system are intended to be serviced in
assembly only. Attempting to remove or repair cer-
tain sub-components may result in personal injury
and/or improper system operation. Only those com-
ponents with approved repair and installation pro-
cedures in the service manual should be serviced.
4.2.4 DRBIIITSAFETY INFORMATION
WARNING: EXCEEDING THE LIMITS OF THE
DRBIIITMULTIMETER IS DANGEROUS. IT
CAN EXPOSE YOU TO SERIOUS OR
POSSIBLY FATAL INJURY. CAREFULLY
READ AND UNDERSTAND THE CAUTIONS
AND THE SPECIFICATIONS LIMITS.
Follow the vehicle manufacturer’s service specifi-
cations at all times.
•Do not use the DRBIIItif it has been damaged.
•Do not use the test leads if insulation is damaged
or if metal is exposed.
•To avoid electrical shock, do not touch the test
leads, tips, or the circuit being tested.
•Choose the proper range and function for the
measurement. Do not try voltage or current mea-
surements that may exceed the rated capacity.
•Do not exceed the limits shown in the table below:
FUNCTION INPUT LIMIT
Volts 0 - 500 peak volts AC
0 - 500 volts DC
Ohms (resistance)* 0 - 1.12 megohms
Frequency Measured
Frequency Generated 0-10kHz
Temperature -58 - 1100°F
-50 - 600°C
* Ohms cannot be measured if voltage is present.
Ohms can be measured only in a non-powered
circuit.
•Voltage between any terminal and ground must
not exceed 500v DC or 500v peak AC.
•Use caution when measuring voltage above 25v
DC or 25v AC.
•Use the low current shunt to measure circuits up
to 10A. Use the high current clamp to measure
circuits exceeding 10A.
•When testing for the presence of voltage or cur-
rent, make sure the meter is functioning cor-
rectly. Take a reading of a known voltage or
current before accepting a zero reading.
•When measuring current, connect the meter in
series with test lead.
• When using the meter function, keep the DRBIIIt
away from spark plug or coil wires to avoid mea-
suring error from outside interference.
6
GENERAL INFORMATION
ProCarManuals.com

4.3 WARNING
4.3.1 VEHICLE DAMAGE WARNINGS
Before disconnecting any control module, make
sure the ignition is “off”. Failure to do so could
damage the module.
When testing voltage or continuity at any control
module, use the terminal side (not the wire end) of
the connector. Do not probe a wire through the
insulation; this will damage it and eventually cause
it to fail because of corrosion.
Be careful when performing electrical tests so as
to prevent accidental shorting of terminals. Such
mistakes can damage fuses or components. Also, a
second code could be set, making diagnosis of the
original problem more difficult.
4.3.2 ROAD TESTING A COMPLAINT
VEHICLE
Some complaints will require a test drive as part
of the repair verification procedure. The purpose of
the test drive is to try to duplicate the diagnostic
code or symptom condition.
CAUTION: Before road testing a vehicle, be
sure that all components are reassembled.
During the test drive, do not try to read the
DRBIIITscreen while in motion. Do not hang
the DRBIIITfrom the rear view mirror or
operate it yourself. Have an assistant
available to operate the DRBIIIT.
4.4 DIAGNOSIS
1. Your diagnostic test procedure must begin with a
thorough visual inspection of the system in ques-
tion for damaged components or disconnected
connectors. For ABS, the brake lamps must be
operational prior to continuing.
2. Connect the DRBIIItto the data link connector
located under the dash. If the DRBIIItdoes not
power up, check the power and ground supplies
to the connector.
3. Select the system in question. Turn the ignition
on. If the DRBIIItdisplays “No Response”, refer
to Communication in the Body Diagnostic Pro-
cedures manual to diagnose the symptom.
4. Read and record all diagnostic trouble codes. For
ABS, if the “CAB Power Feed Circuit” diagnostic
trouble code is present, it must be repaired prior
to addressing any other DTC’s. If any additional
codes are present, proceed to the appropriate
test.
5. For ABS, if there are no diagnostic trouble codes
present, select ‘‘Inputs/Outputs’’ and read the
brake switch input as your press and release the
brake pedal. If the display does not match the
state of the pedal, perform the proper test. For a
problem with the amber “ABS” warning indica-
tor, refer to the proper test.
6. For ABS, if no other problems are found, it will
be necessary to road test the vehicle. THE
DRBIIItMUST NOT BE CONNECTED TO
THE DATA LINK CONNECTOR WHEN
ROAD TESTING FOR PROPER ANTILOCK
OPERATION. THE SYSTEM IS DISABLED
WHILE IN DIAGNOSTIC MODE. Perform
several antilock stops from above 50 Km/h (30
mph) and then repeat steps 2, 3, and 4. If any
diagnostic trouble codes are present, proceed to
the appropriate test.
7. For ABS, the following conditions should be
considered ‘‘NORMAL’’operation, and no repairs
should be attempted to correct them.
– Brake pedal feedback during an ABS stop
(clicking, vibrating)
– Clicking, groaning or buzzing at 10 Km/h (6
mph) (drive off self test)
– Groaning noise during an ABS stop
– Slight brake pedal drop and pop noise when
ignition is initially turned on
– Brake pedal ratcheting down at the end of an
ABS stop
8. If the complaint is ABS ‘‘cycling’’ at the end of a
stop at low speeds, it may be caused by a
marginal wheel speed sensor signal. The sensor
air gap, tone wheel condition, and/or brakes
hanging up are possible causes of this condition.
9. After a road test in which no problems were
found, refer to any Technical Service Bulletins
that may apply.
5.0 REQUIRED TOOLS AND
EQUIPMENT
DRBIIIt(diagnostic read-out box)
jumper wires
ohmmeter
voltmeter
test light
6.0 GLOSSARY OF TERMS
ABS antilock brake system
AC alternating current
APM adjustable pedals module
BCM Body Control Module
7
GENERAL INFORMATION
ProCarManuals.com

CAB controller antilock brake
DC direct current
DLC data link connector
DRB diagnostic read-out box
DTC diagnostic test code
EMI electro magnetic interference
EVBP Electronic Variable Brake Propor-
tioning
HCU hydraulic control unit
HZ Hertz
JBLK junction block
JTEC Jeep and Truck Engine Controller
LF left front
LR left rear
PCI Programmable Communication In-
terface
PCM Powertrain Control Module
PDC power distribution center
P/M pump motor
RF right front
RR right rear
SOL solenoid
WSS wheel speed sensor
8
GENERAL INFORMATION
ProCarManuals.com

7.0
DIAGNOSTIC INFORMATION AND
PROCEDURES
9
ProCarManuals.com

Symptom:
PEDAL SENSOR OPEN/SHORTED TO BATTERY
When Monitored and Set Condition:
PEDAL SENSOR OPEN/SHORTED TO BATTERY
When Monitored: Constantly.
Set Condition: When the APM detects the voltage on the Sense circuit is too high.
POSSIBLE CAUSES
MOTOR/SENSOR SHORTED OR OPEN
SENSE CIRCUIT SHORT TO BATTERY OR TO SENSOR FEED CIRCUIT
APM-INTERNAL FAULT
INTERMITTENT DTC
TEST ACTION APPLICABILITY
1 With the DRBIIIt, erase DTC’s.
With the DRBIIIt, read DTC’s.
Does the DRBIIItdisplay PEDAL SENSOR OPEN/SHORTED TO BATTERY DTC
active?
All
Yes →Go To 2
No →Go To 4
2 Disconnect the Adjustable Pedals Motor/Sensor harness connector.
Turn the ignition on.
With the DRBIIIt, read the active DTCs.
Does the DRBIIItdisplay PEDAL SENSOR OPEN/SHORTED TO BATTERY?
All
Yes →Go To 3
No →Replace the Adjustable Pedals Motor/Sensor assembly in accor-
dance with the Service Information.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
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ADJUSTABLE PEDALS
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TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Adjustable Pedals Motor/Sensor harness connector.
Disconnect the Adjustable Pedals Module harness connector.
Note: Check connector - Clean/repair as necessary.
Turn the ignition on.
Check the Sense circuit for a short to battery and for a short to the Sensor Feed
circuit.
Is the Sense circuit shorted?
All
Yes →Repair the Sense circuit for a short to battery or to the Sensor
Feed circuit.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Replace and program theAdjustable Pedals Module in accordance
with the Service Information..
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
4 Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Refer to any Hotline letters or Technical Service Bulletins that may apply.
Were any problems found?
All
Yes →Repair as necessary.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Test Complete.
11
ADJUSTABLE PEDALS
PEDAL SENSOR OPEN/SHORTED TO BATTERY — Continued
ProCarManuals.com

Symptom:
PEDAL SENSOR SHORTED TO GROUND
When Monitored and Set Condition:
PEDAL SENSOR SHORTED TO GROUND
When Monitored: Constantly
Set Condition: When the APM detects a ground condition at the Sense circuit.
POSSIBLE CAUSES
MOTOR/SENSOR ASSEMBLY SHORTED TO GROUND
APM-SENSE CIRCUIT GROUNDED
INTERMITTENT DTC
TEST ACTION APPLICABILITY
1 With the DRBIIIt, erase DTC’s.
With the DRBIIIt, read DTC’s.
Does the DRBIIItdisplay PEDAL SENSOR SHORTED TO GROUND DTC active?
All
Yes →Go To 2
No →Go To 3
2 Disconnect the Adjustable Pedals Motor/Sensor harness connector.
Turn the ignition on.
With the DRBIIIt, read the active DTCs.
Does the DRBIIItdisplay SENSOR WIRING SHORTED TO GROUND?
All
Yes →Inspect for and correct wiring damage. If no damage is found,
replace and program theAdjustable Pedals Module in accordance
with the Service Information..
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Repair any Motor/Sensor assembly wiring concerns. If no wring
concerns are found, replace the Adjustable Pedals Motor/Sensor
assembly.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
3 Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Refer to any Hotline letters or Technical Service Bulletins that may apply.
Were any problems found?
All
Yes →Repair as necessary.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Test Complete.
12
ADJUSTABLE PEDALS
ProCarManuals.com

Symptom:
PEDAL SW STUCK FORWARD
When Monitored and Set Condition:
PEDAL SW STUCK FORWARD
When Monitored: Constantly
Set Condition: When the Adjustable Pedals module detects battery voltage on the
Adjustable Pedals Switch FWD circuit for more than 20 seconds.
POSSIBLE CAUSES
ADJUSTABLE PEDALS MODULE INTERNAL FAULT
SWITCH FAILURE
INTERMITTENT DTC
FWD CIRCUIT SHORTED TO BATTERY OR TO BATTERY FEED CIRCUIT
TEST ACTION APPLICABILITY
1 With the DRBIIIt, erase DTC’s.
Turn the ignition on.
With the DRBIIIt, read DTC’s.
Does the DRBIIItdisplay PEDAL SW STUCK FORWARD DTC active?
All
Yes →Go To 2
No →Go To 4
2 Disconnect the Adjustable Pedals switch connector.
Turn the ignition on.
With the DRBIIIt, read DTC’s.
Does the DRBIIItdisplay PEDAL SW STUCK FORWARD DTC active?
All
Yes →Go To 3
No →Replace the Adjustable Pedals Switch.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
3 Turn the ignition off.
Disconnect the Adjustable Pedals Module harness connector.
Disconnect the Adjustable Pedals switch connector.
Turn the ignition ON.
Check the FWD and BATTERY FEED circuits for a short to battery, to ground and
to each other.
Is there any circuit short?
All
Yes →Repair the circuit short.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Replace and program theAdjustable Pedals Module in accordance
with the Service Information.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
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ADJUSTABLE PEDALS
ProCarManuals.com

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Refer to any Hotline letters or Technical Service Bulletins that may apply.
Were any problems found?
All
Yes →Repair as necessary.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Test Complete.
14
ADJUSTABLE PEDALS
PEDAL SW STUCK FORWARD — Continued
ProCarManuals.com

Symptom:
PEDAL SW STUCK REARWARD
When Monitored and Set Condition:
PEDAL SW STUCK REARWARD
When Monitored: Constantly
Set Condition: When the Adjustable Pedals module detects battery voltage on the
Adjustable Pedals Switch AFT circuit for more than 20 seconds.
POSSIBLE CAUSES
ADJUSTABLE PEDALS MODULE INTERNAL FAULT
SWITCH FAILURE
INTERMITTENT DTC
AFT CIRCUIT SHORTED TO BATTERY OR TO BATTERY FEED CIRCUIT
TEST ACTION APPLICABILITY
1 With the DRBIIIt, erase DTC’s.
Turn the ignition on.
With the DRBIIIt, read DTC’s.
Does the DRBIIItdisplay PEDAL SW STUCK REARWARD DTC active?
All
Yes →Go To 2
No →Go To 4
2 Disconnect the Adjustable Pedals switch connector.
Turn the ignition on.
With the DRBIIIt, read DTC’s.
Does the DRBIIItdisplay PEDAL SW STUCK REARWARD DTC active?
All
Yes →Go To 3
No →Replace the Adjustable Pedals Switch.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
3 Turn the ignition off.
Disconnect the Adjustable Pedals Module harness connector.
Disconnect the Adjustable Pedals switch connector.
Turn the ignition ON.
Check the AFT and BATTERY FEED circuits for a short to battery, to ground and to
each other.
Is there any circuit short?
All
Yes →Repair the circuit short.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Replace and program theAdjustable Pedals Module in accordance
with the Service Information.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
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ADJUSTABLE PEDALS
ProCarManuals.com

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wire harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Refer to any Hotline letters or Technical Service Bulletins that may apply.
Were any problems found?
All
Yes →Repair as necessary.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Test Complete.
16
ADJUSTABLE PEDALS
PEDAL SW STUCK REARWARD — Continued
ProCarManuals.com

Symptom:
SYSTEM OVER VOLTAGE
When Monitored and Set Condition:
SYSTEM OVER VOLTAGE
When Monitored: Whenever the module is awake
Set Condition: When the APM detects 3 consecutive J1850 Bus messages indicating
vehicle voltage over 15.94 VDC.
POSSIBLE CAUSES
VEHICLE VOLTAGE HIGH
APM -- INTERNAL FAILURE
TEST ACTION APPLICABILITY
1 With the DRBIIIt, read the vehicle voltage status.
Does the DRBIIItdisplay a high voltage concern? All
Yes →Refer to Charging information for the related symptom(s).
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Replace and program theAdjustable Pedals Module in accordance
with the Service Information.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
17
ADJUSTABLE PEDALS
ProCarManuals.com

Symptom:
SYSTEM UNDER VOLTAGE
When Monitored and Set Condition:
SYSTEM UNDER VOLTAGE
When Monitored: Any time that the module is awake.
Set Condition: When the APM detects 3 consecutive J1850 Vehicle Battery Voltage
messages indicating a battery voltage less than 9 VDC.
POSSIBLE CAUSES
VEHICLE VOLTAGE LOW
APM -- INTERNAL FAILURE
TEST ACTION APPLICABILITY
1 With the DRBIIIt, read the vehicle voltage status.
Does the DRBIIItdisplay a low voltage concern? All
Yes →Refer to Charging information for the related symptom(s).
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
No →Replace and program theAdjustable Pedals Module in accordance
with the Service Information.
Perform ADJUSTABLE PEDALS VERIFICATION TEST - VER
1.
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ADJUSTABLE PEDALS
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