
TEST ACTION APPLICABILITY
4WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
Refill the cooling system in accordance with the Service Information.
Start the engine.
Allow the engine to reach normal operating temperature.
Turn the engine off.
Allow the engine coolant to cool down to a temperature of 50ÉC (122ÉF).
Start the engine.
Allow the engine to reach normal operating temperature.
Turn the engine off.
View repairAll
Repair
Go To 5
5WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
NOTE: The heater's control unit will store up to five DTCs in its memory.
NOTE: If the heater's control unit detects a new fault in the system, one that
is not already stored in its memory, it will clear the oldest of the five stored
DTCs, and it will store the new fault's DTC.
NOTE: If the heater's control unit detects a reoccurrence of a stored fault,
it will overwrite that fault's DTC with the most recent occurrence.
Turn the ignition on.
Verify that the Cabin Heater or Heater Booster is switched off.
Set the blend control to the max heat position and the mode control to the floor
position.
Start the engine. Allow the engine to idle.
With the DRBIII, monitor for Cabin Heater or Heater Booster Module DTCs while
performing the following step.
NOTE: Do not disconnect the vehicle's battery or the heater's main power
supply while the heater is in operation or in run-down mode. Failure to
follow these instructions can result in excess emissions from the heater
during heater operation.
Switch the Cabin Heater or Heater Booster on. If necessary, allow the heater to run
through at least one cycle of operation (approximately 10 minutes), and then turn the
heater off.
Turn the engine off.
Does the DRBIIItdisplay any DTCs?All
Overheating Related DTC(s) Reset
Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
Ovrheatng DTC(s) clear, Other DTC(s) Set
Return to the symptom list and choose the symptom(s).
Perform HEATER VERIFICATION TEST - VER 1.
No DTCs Present
Test Complete.
95
CABIN HEATER
HEATER IN LOCKOUT MODE ÐContinued

Symptom:
NO CAN COMMUNICATION WITH ABS
POSSIBLE CAUSES
DTC PRESENT
OPEN CAN CIRCUITS AT INSTRUMENT CLUSTER
INSTRUMENT CLUSTER
CHECK POWERS AND GROUNDS TO THE AFFECTED MODULE
OPEN CAN CIRCUITS AT CAB
CONTROLLER ANTILOCK BRAKE
TEST ACTION APPLICABILITY
1 With the DRBIIIt, record and erase DTC's.
Cycle the ignition switch from ON to OFF to ON.
With the DRBIIIt, read DTC's.
Did this DTC reset?All
Ye s!Go To 2
No!The conditions that caused this code to set are not present at this
time. Using the wiring diagram/schematic as a guide, inspect the
wiring and connectors for an intermittent condition.
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRBIIIt, check the TCM, ECM, and the Shifter Assembly for this same or
similar ABS message error DTC.
Is the same or similar DTC set in the other modules?All
Ye s!Go To 3
No!Go To 5
3 Turn the ignition off.
Disconnect the Controller Antilock Brake harness connector.
Check each power and ground circuit to the module.
Were any problems found?All
Ye s!Refer to the wiring diagrams located in the service information to
help isolate an open or shorted condition. Repair as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off to the lock position.
Disconnect the Controller Antilock Brake harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the CAB harness connector.
Is the resistance 60 ohms, 3.0 ohms?All
Ye s!Replace the Controller Antilock Brake in accordance with the
service information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+) or the CAN C Bus (-) circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
188
INSTRUMENT CLUSTER

Symptom:
NO CAN COMMUNICATION WITH ECM
POSSIBLE CAUSES
DTC PRESENT
OPEN CAN CIRCUITS AT INSTRUMENT CLUSTER
INSTRUMENT CLUSTER
CHECK POWERS AND GROUNDS TO THE AFFECTED MODULE
OPEN CAN CIRCUITS AT ECM
ECM
TEST ACTION APPLICABILITY
1 With the DRBIIIt, record and erase DTC's.
Cycle the ignition switch from ON to OFF to ON.
With the DRBIIIt, read DTC's.
Did this DTC reset?All
Ye s!Go To 2
No!The conditions that caused this code to set are not present at this
time. Using the wiring diagram/schematic as a guide, inspect the
wiring and connectors for an intermittent condition.
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRBIIIt, check the TCM, ABS, and the ATC Module for this same or similar
ECM message error DTC.
Is the same or similar DTC set in the other modules?All
Ye s!Go To 3
No!Go To 5
3 Turn the ignition off.
Disconnect the ECM harness connector.
Check each power and ground circuit to the module.
Were any problems found?All
Ye s!Refer to the wiring diagrams located in the service information to
help isolate an open or shorted condition. Repair as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off to the lock position.
Disconnect the ECM harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the ECM harness connector.
Is the resistance 120 ohms, 3.0 ohms?All
Ye s!Replace the ECM in accordance with the service information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+) or the CAN C Bus (-) circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
190
INSTRUMENT CLUSTER

Symptom:
NO CAN COMMUNICATION WITH TCM
POSSIBLE CAUSES
DTC PRESENT
OPEN CAN CIRCUITS AT INSTRUMENT CLUSTER
INSTRUMENT CLUSTER
CHECK POWERS AND GROUNDS TO THE AFFECTED MODULE
OPEN CAN CIRCUITS AT TCM
TCM
TEST ACTION APPLICABILITY
1 With the DRBIIIt, record and erase DTC's.
Cycle the ignition switch from ON to OFF to ON.
With the DRBIIIt, read DTC's.
Did this DTC reset?All
Ye s!Go To 2
No!The conditions that caused this code to set are not present at this
time. Using the wiring diagram/schematic as a guide, inspect the
wiring and connectors for an intermittent condition.
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRBIIIt, check the ABS, ECM for this same or similar TCM message error
DTC.
Is the same or similar DTC set in the ECM?All
Ye s!Go To 3
No!Go To 5
3 Turn the ignition off.
Disconnect the TCM harness connector.
Check each power and ground circuit to the module.
Were any problems found?All
Ye s!Refer to the wiring diagrams located in the service information to
help isolate an open or shorted condition. Repair as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off to the lock position.
Disconnect the TCM harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the TCM harness connector.
Is the resistance 60 ohms, 3.0 ohms?All
Ye s!Replace the TCM in accordance with the service information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+) or the CAN C Bus (-) circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
192
INSTRUMENT CLUSTER

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:
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