TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the DRBIIItfrom the DLC.
Disconnect the Shifter Assembly harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, probe the K-ABS, Shifter Assembly
circuit.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s!Go To 5
No!Go To 6
5 Turn the ignition off.
Disconnect the Controller Antilock Brake harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, probe the K-ABS, Shifter Assembly
circuit.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s!Repair the K-ABS, Shifter Assembly circuit for a short to voltage.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Replace the Controller Antilock Brake in accordance with the
service information.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
6 Turn the ignition off.
Disconnect the Shifter Assembly harness connector.
Disconnect the DRBIIItfrom the DLC.
Measure the resistance of the K-ABS, Shifter Assembly circuit between the Shifter
Assembly connector and the DLC.
Is the resistance below 5.0 ohms?All
Ye s!Replace the Shifter Assembly in accordance with the Service
Information.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Repair the K-ABS, Shifter Assembly circuit for an open.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
125
COMMUNICATION
*NO RESPONSE FROM SHIFTER ASSEMBLY ÐContinued
Symptom:
BLOWER STAGE 1 HIGH OR OPEN (ACTIVE)
POSSIBLE CAUSES
BLOWER MOTOR
BLOWER MOTOR DRIVER CIRCUIT(S) SHORTED TO VOLTAGE
BLOWER MOTOR DRIVER CIRCUIT(S) OPEN
BLOWER MOTOR RESISTOR BLOCK
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST ACTION APPLICABILITY
1 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Blower Motor harness connector.
Connect a fused jumper wire between Battery (+) and Blower Motor cavity 1.
Connect a jumper wire between ground and Blower Motor cavity 2.
Does the Blower Motor run at full speed?All
Ye s!Go To 2
No!Replace the Blower Motor in accordance with the Service Infor-
mation.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Blower Motor Resistor Block harness connector.
Disconnect the Blower Motor harness connector.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Turn the ignition on.
Measure the voltage of each of the Blower Motor Driver circuits (Low, M1, M2, High).
Is the voltage above 0.2 volts on any of the circuits?All
Ye s!Repair each circuit with voltage above 0.2 volts for a short to
voltage.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Disconnect the Blower Motor Resistor Block harness connector.
Disconnect the Blower Motor harness connector.
Measure the resistance of the Blower Motor Driver circuits (Low, M1, M2, High)
between the Automatic Temperature Control (ATC) C2 harness connector and the
Blower Motor Resistor Block harness connector.
Measure the resistance of the Blower Motor High Driver circuit between the
Automatic Temperature Control (ATC) C2 harness connector and the Blower Motor
harness connector.
Is the resistance below 5.0 ohms on each of the circuits?All
Ye s!Go To 4
No!Repair each circuit with a resistance above 5.0 ohms for an open.
Perform BODY VERIFICATION TEST - VER 1.
144
HEATING & A/C
TEST ACTION APPLICABILITY
4 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Blower Motor Resistor Block harness connector.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 1.
The approximate resistance should be 1.4 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 3.
The approximate resistance should be 0.8 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 4.
The approximate resistance should be 1.6 ohms.
Is the resistance as specified for each circuit?All
Ye s!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Blower Motor Resistor Block in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
145
HEATING & A/C
BLOWER STAGE 1 HIGH OR OPEN (ACTIVE) ÐContinued
Symptom:
BLOWER STAGE 1 SHORTED LOW (ACTIVE)
POSSIBLE CAUSES
BLOWER MOTOR FUSE
BLOWER MOTOR
BLOWER MOTOR DRIVER CIRCUIT(S) SHORTED TO GROUND
FUSED B+ CIRCUIT SHORTED TO GROUND
BLOWER MOTOR RESISTOR BLOCK
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Remove and inspect the Blower Motor Fuse, and replace it if necessary.
NOTE: All of the following criteria must be met in order to successfully run
the ATC Function Test.
Place the shift lever in Park.
Turn the ignition on.
With the DRBIIIt, record and erase ATC DTC's.
Start the engine. Allow the engine to reach normal operating temperature.
Set the blower to high speed.
Press the Air Conditioning switch On.
With the DRBIIIt, verify that the ambient temperature is above 59ÉF (15ÉC), the
refrigerant pressure is between 29 and 348 PSI (2 and 24 bar), the evaporator
temperature is above 36.5ÉF (2.5ÉC), and the coolant temperature is above 158ÉF
(70ÉC).
With the DRBIIItin Automatic Temperature Control (ATC), select System Tests and
select ATC Function Test. When the ATC Function Test is complete, proceed as
follows:
With the DRBIIIt, read the active ATC DTCs.
Does the DRBIIItdisplay: BLOWER STAGE ONE SHORTED LOW?All
Ye s!Go To 2
No!Refer to the wiring diagrams located in the service information to
help isolate a possible intermittent short to ground condition.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Disconnect the Blower Motor harness connector.
Connect a fused jumper wire between Battery (+) and Blower Motor cavity 1.
Connect a jumper wire between ground and Blower Motor cavity 2.
Does the Blower Motor run at full speed?All
Ye s!Go To 3
No!Replace the Blower Motor in accordance with the Service Infor-
mation. Remove and inspect the Blower Motor Fuse, and replace
it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
146
HEATING & A/C
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Blower Motor Resistor harness connector.
Disconnect the Blower Motor harness connector.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Measure the resistance between ground and each of the Blower Motor Driver circuits
(Low, M1, M2, High).
Is the resistance below 10k ohms on any of the circuits?All
Ye s!Repair each circuit with a resistance below 10k ohms for a short
to ground. Remove and inspect the Blower Motor Fuse, and
replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off.
Remove the Blower Motor Fuse.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Measure the resistance between ground and the Fused B+ circuit.
Is the resistance below 10k ohms?All
Ye s!Repair the Fused B+ circuit for a short to Ground. Remove and
inspect the Blower Motor Fuse, and replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 5
5 Turn the ignition off.
Disconnect the Blower Motor Resistor Block harness connector.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 1.
The approximate resistance should be 1.4 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 3.
The approximate resistance should be 0.8 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 4.
The approximate resistance should be 1.6 ohms.
Is the resistance as specified for each circuit?All
Ye s!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information. Remove and inspect the Blower
Motor Fuse, and replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Blower Motor Resistor Block in accordance with the
Service Information. Remove and inspect the Blower Motor Fuse,
and replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
147
HEATING & A/C
BLOWER STAGE 1 SHORTED LOW (ACTIVE) 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
TEST ACTION APPLICABILITY
5 Turn the ignition off to the lock position.
Disconnect the Instrument Cluster C1 harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Instrument Cluster harness connector.
Is the resistance 60 ohms, 3.0 ohms?All
Ye s!Replace the Instrument Cluster 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.
189
INSTRUMENT CLUSTER
NO CAN COMMUNICATION WITH ABS ÐContinued
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