display does not match the state of the pedal,
perform the proper test. For a problem with the
ªABSº warning indicator, refer to the proper test.
6. If no other problems are found, it will be neces-
sary to road test the vehicle.THE DRBIIIt
MUST NOT BE CONNECTED TO THE
DATA LINK CONNECTOR WHEN ROAD
TESTING FOR PROPER ANTILOCK OP-
ERATION. 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. 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 12 Km/h (8
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
oscilloscope
6.0 GLOSSARY OF TERMS
ABSantilock brake system
ACalternating current
BCMbody control module
BSbrake switch
BLSbrake lamp switch
CABcontroller antilock brakeDCdirect current
DLCdata link connector
DRBIIItdiagnostic read-out box
DTCdiagnostic test code
EBDelectronic brake distribution
ECMelectronic control module
HCUhydraulic control unit
HZHertz
ICinstrument cluster
LFleft front
LRleft rear
PMpump motor
RFright front
RRright rear
SOLsolenoid
TCStraction control system
TCSStraction control system switch
VSSvehicle speed signal
WSSwheel speed sensor
7
GENERAL INFORMATION
Symptom:
BRAKE PRESSURE SENSOR CIRCUIT
POSSIBLE CAUSES
BRAKE PRESSURE SENSOR CIRCUIT INTERMITTENT DTC
BRAKE PRESSURE SENSOR CIRCUIT SHORT TO VOLTAGE
BRAKE PRESSURE SENSOR CIRCUIT SHORT TO GROUND
BRAKE PRESSURE SENSOR CIRCUIT OPEN
BRAKE PRESSURE SENSOR
ANTI-LOCK BRAKE CONTROLLER
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Turn the ignition on.
With the DRBIIIt, read DTCs. Record DTC information.
NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
NOTE: Before continuing, make sure that the Brake Lamp switch is ad-
justed correctly and functioning properly. Adjust or replace the switch as
necessary in accordance with the Service Information.
With the DRBIIIt, erase DTCs.
Road test the vehicle and perform several braking maneuvers.
With the DRBIIIt, read DTCs.
Does this DTC reset?All
Ye s!Go To 2
No!Go To 6
2 Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Disconnect the CAB harness connector.
Turn the ignition on.
Measure the voltage of the Brake Pressure Sensor signal circuit.
Measure the voltage of the Brake Pressure Sensor ground circuit.
Measure the voltage of the Brake Pressure Sensor 5 volt supply circuit.
Is there voltage present on any of the circuits?All
Ye s!Repair the Brake Pressure Sensor circuit(s) for a short to voltage.
No!Go To 3
3 Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Disconnect the CAB harness connector.
Measure the resistance between ground and the Brake Pressure Sensor signal
circuit.
Measure the resistance between ground and the Brake Pressure Sensor 5 volt supply
circuit.
Is the resistance below 5.0 ohms for either circuit?All
Ye s!Repair the Brake Pressure Sensor circuit(s) for a short to ground.
No!Go To 4
15
BRAKES (CAB)
TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Disconnect the CAB harness connector.
Measure the resistance of the Brake Pressure Sensor signal circuit.
Measure the resistance of the Brake Pressure Sensor ground circuit.
Measure the resistance of the Brake Pressure Sensor 5 volt supply circuit.
Is the resistance above 5.0 ohms for any of the circuits?All
Ye s!Repair the Brake Pressure Sensor circuit(s) for an open
No!Go To 5
5 Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Inspect the harness and connectors related to this circuit. If any problems are found,
repair as necessary.
If no problems are found, replace the Brake Pressure Sensor in accordance with the
Service Information.
With the DRBIIIt, clear DTCs.
Road test the vehicle and perform several braking maneuvers.
With the DRBIIIt, read DTCs.
Does this DTC reset?All
Ye s!Replace the CAB in accordance with the Service Information.
No!Test Complete.
6 The condition that set this DTC is not present at this time.
Monitor the DRBIIItwhile wiggle testing the related harness and connectors. Look
for any related parameters to change or for the DTC to reset.
Inspect the related harness and connectors.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out, or corroded terminals.
Were any problems found?All
Ye s!Repair as necessary.
No!Test Complete.
16
BRAKES (CAB)
BRAKE PRESSURE SENSOR CIRCUIT ÐContinued
Symptom:
CAN COMMUNICATION ERROR
POSSIBLE CAUSES
CAN DTCS PRESENT IN OTHER MODULES
INTERMITTENT CAN COMMUNICATION ERROR DTC
DAMAGED CAB/CAB HARNESS CONNECTOR
CAN CIRCUIT(S) SHORT TO VOLTAGE
CAN CIRCUIT(S) SHORTED TOGETHER
CAN CIRCUIT(S) SHORT TO GROUND
CAN CIRCUIT(S) OPEN
FUSED OPTIONAL EQUIPMENT RELAY OUTPUT CIRCUIT OPEN
FUSED B(+) CIRCUIT OPEN
GROUND CIRCUIT OPEN
ANTI-LOCK BRAKE CONTROLLER
TEST ACTION APPLICABILITY
1 Turn the ignition on.
NOTE: Diagnose any Steering Angle Sensor DTCs that are present in this
module before continuing.
With the DRBIIIt, read DTCs in the Engine Control Module, Transmission Control
Module, and Instrument Cluster.
Are there any CAN communication DTCs present in any of these modules?All
Ye s!Refer to the diagnostic procedures for any CAN DTCs in ECM,
TCM and Cluster before proceeding with this test.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 2
2NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
Turn the ignition on.
With the DRBIIIt, erase DTCs.
Turn the ignition off.
Start the engine.
With the DRBIIIt, read DTCs.
Does this DTC reset?All
Ye s!Go To 3
No!Go To 11
3 Turn the ignition off.
Disconnect the CAB harness connector.
Inspect the CAB/CAB harness connector for damage.
Is there any broken, bent, pushed out, corroded or spread terminals?All
Ye s!Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 4
25
BRAKES (CAB)
Symptom:
DRIVE TEST ERROR
POSSIBLE CAUSES
INTERMITTENT DRIVE TEST ERROR DTC
STEERING COMPONENT INSPECTION
LATERAL ACCELERATION SENSOR CIRCUIT SHORT TO VOLTAGE
LATERAL ACCELERATION SENSOR CIRCUIT SHORT TO GROUND
LATERAL ACCELERATION SENSOR CIRCUIT OPEN
LATERAL ACCELERATION SENSOR
ANTI-LOCK BRAKE CONTROLLER
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Turn the ignition on.
With the DRBIIIt, read DTCs. Record DTC information.
NOTE: If any other DTC is set along with this DTC, diagnose the other
DTC(s) first.
NOTE: Electromagnetic (radio) interference can cause an intermittent
system malfunction by interrupting communication between the sensor
and the CAB.
With the DRBIIIt, erase DTCs.
With the DRBIIIt, perform the road test procedure in accordance with the Service
Information.
With the DRBIIIt, read DTCs.
NOTE: Failure to perform the road test procedure properly can cause this
DTC to set.
NOTE: This DTC can only be cleared by a fault free road test.
Does this DTC reset?All
Ye s!Go To 2
No!Go To 7
2NOTE: When the vehicle is in a turn, the ESP compares the Steering Angle
Sensor value and the speed of the inner and outer wheels to determine if the
values are plausible.
Inspect the front end and steering components for damage or misalignment.
Inspect the Lateral Acceleration Sensor for correct mounting and installation.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Were any problems found?All
Ye s!Repair or replace components as necessary in accordance with the
Service Information.
No!Go To 3
29
BRAKES (CAB)
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Lateral Acceleration Sensor harness connector.
Disconnect the CAB harness connector.
Turn the ignition on.
Measure the voltage on all 4 of the Lateral Acceleration Sensor signal circuits.
Measure the voltage of the Lateral Acceleration Sensor ground circuit.
There should be no voltage present on any of the circuits.
Measure the resistance between the Lateral Acceleration supply circuit and all 4 of
the Lateral Acceleration Sensor signal circuits.
The resistance between the circuits should be above 5.0 ohms.
Were there any problems found?All
Ye s!Repair the shorted Lateral Acceleration Sensor circuit(s).
No!Go To 4
4 Turn the ignition off.
Disconnect the Lateral Acceleration Sensor harness connector.
Disconnect the CAB harness connector.
Measure the resistance between the Lateral Acceleration Sensor ground and the 4
Lateral Acceleration Sensor signal circuits.
Measure the resistance between ground and the 4 Lateral Acceleration Sensor signal
circuits.
Measure the resistance between ground and the Lateral Acceleration Sensor supply
circuit.
Is the resistance below 5.0 ohms for any of the circuits?All
Ye s!Repair the Lateral Acceleration Sensor circuit(s) for a short to
ground.
No!Go To 5
5 Turn the ignition off.
Disconnect the Lateral Acceleration Sensor harness connector.
Disconnect the CAB harness connector.
Measure the resistance of the Lateral Acceleration Sensor supply circuit.
Measure the resistance of the Lateral Acceleration Sensor ground circuit.
Measure the resistance of the 4 Lateral Acceleration Sensor signal circuits.
Is the resistance above 5.0 ohms for any of the circuits?All
Ye s!Repair the Lateral Acceleration Sensor circuit(s) for an open
No!Go To 6
6 Turn the ignition off.
Disconnect the Lateral Acceleration Sensor harness connector.
Inspect the harness and connectors related to this circuit. If any problems are found,
repair as necessary.
If no problems are found, replace the Lateral Acceleration Sensor in accordance with
the Service Information.
With the DRBIIIt, clear DTCs.
With the DRBIIIt, perform the road test procedure.
With the DRBIIIt, read DTCs.
Does this DTC reset?All
Ye s!Replace the CAB in accordance with the Service Information.
No!Test Complete.
30
BRAKES (CAB)
DRIVE TEST ERROR ÐContinued
Symptom:
INCORRECT TONE WHEEL
When Monitored and Set Condition:
INCORRECT TONE WHEEL
When Monitored: Ignition On - Continuously
Set Condition: When continuous ABS control is active for one minute on one or more
wheels OR interference on one or more wheels OR deviation of two wheel speeds at either
side of vehicle by 6 km/h (4 mph) or at the front axle by 10 km/h (7 mph). If at least one
wheel is 5 km/h (3 mph) or less, a wheel speed deviation of adjoining wheels of 12 km/h (8
mph) is allowed.
POSSIBLE CAUSES
INTERMITTENT INCORRECT TONE WHEEL DTC
INCORRECT TIRES ON VEHICLE
TIRE CIRCUMFERENCES NOT MATCHING
WHEEL SPEED SENSOR CIRCUIT SHORT TO VOLTAGE
INCORRECT TONE WHEEL
WHEEL SPEED SENSOR CIRCUIT SHORT TO GROUND
DAMAGED WHEEL BEARING
WHEEL SPEED SENSOR CIRCUIT OPEN
DAMAGED BRAKE LININGS/COMPONENTS
WHEEL SPEED SENSOR CIRCUITS SHORTED TOGETHER
WHEEL SPEED SENSOR
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTCs.
With the DRBIIIt, erase DTCs.
Turn the ignition off.
Turn the ignition on.
Road test the vehicle.
During the road test, drive the vehicle above 100 km/h (62 mph) for at least 3 minutes
and perform several stops and Antilock stops.
Stop the vehicle.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay INCORRECT TONE WHEEL?All
Ye s!Go To 2
No!Go To 13
32
BRAKES (CAB)
TEST ACTION APPLICABILITY
2 Turn the ignition off.
Inspect the tire sizes on the vehicle.
Is a smaller than production tire or spare tire being used?All
Ye s!Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition off.
Measure all the tire circumferences.
Do all the tire circumferences match?All
Ye s!Go To 4
No!Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
4 Turn the ignition off.
Inspect the tone wheel(s) for damage, missing teeth, cracks, or looseness.
NOTE: Refer to the service manual information, if necessary, for procedures
or specifications.
Are one or more tone wheel(s) loose or damaged?All
Ye s!Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 5
5 Turn the ignition off.
Inspect the wheel bearings for excessive runout or clearance.
NOTE: Refer to the service information, if necessary, for procedures or
specifications.
Is the wheel bearing clearance within specifications?All
Ye s!Go To 6
No!Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
6 Turn the ignition off.
Visually inspect the brakes for locking up due to lining contamination or overheating.
Inspect all brake components for any condition that would cause a variation in wheel
speed.
Is any component damaged?All
Ye s!Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 7
7 Turn the ignition on.
With the DRBIIItin Sensors, monitor ALL the Wheel Speed Sensor signals while an
assistant drives the vehicle.
Slowly accelerate from a stop to 65 km/h (40 mph).
NOTE: Wheel Speed should not vary by more than 10% from wheel to wheel
when driving in a straight line.
Do any of the Wheel Speed Sensor signals vary by greater than 10% while driving in
a straight line?All
Ye s!Go To 8
No!Go To 13
33
BRAKES (CAB)
INCORRECT TONE WHEEL ÐContinued