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Symptom:
FCM, HVAC COMMUNICATION FAULT
When Monitored and Set Condition:
FCM, HVAC COMMUNICATION FAULT
When Monitored: With the ignition in run, and the IOD fuse installed.
Set Condition: The FCM does not receive any messages from the Automatic Temperature
Control (ATC) module or the A/C Heater Control (MTC) for at least 20 seconds.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE HVAC
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the A/C Heater Control (MTC) or the
Automatic Temp Control (ATC).
Was the DRB able to I/D or communicate with the HVAC or the ATC?All
Ye s®Go To 2
No®Refer to the Communication category for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRB, erase DTC's.
Cycle the ignition switch from off to on and wait approximately 1 minute.
With the DRB, read DTC's.
Did this DTC reset?All
Ye s®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
345
COMMUNICATION
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Symptom:
FCM, PCI INTERNAL FAULT
When Monitored and Set Condition:
FCM, PCI INTERNAL FAULT
When Monitored: The FCM detects an internal fault.
Set Condition: The DTC will set if the FCM detects an internal fault.
POSSIBLE CAUSES
FCM, PCI INTERNAL FAULT
TEST ACTION APPLICABILITY
1 Connect the DRB to the Data Link Connector.
Turn the ignition on.
With the DRB, erase FCM DTC's.
Turn the ignition off then turn the ignition on.
With the DRB, read FCM DTC's.
Did this DTC reset?All
Ye s®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
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COMMUNICATION
Page 376 of 4284

Symptom:
FCM, PCM COMMUNICATION FAULT
When Monitored and Set Condition:
FCM, PCM COMMUNICATION FAULT
When Monitored: With the ignition in run, and the IOD fuse installed.
Set Condition: The FCM does not receive any messages from the PCM for at least 5
seconds.
POSSIBLE CAUSES
PCM COMMUNICATION FAULT
ATTEMPT TO COMMUNICATE WITH THE PCM
PCI BUS CIRCUIT OPEN
POWERTRAIN CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, enter Instrument Cluster, System Tests then PCM Monitor.
Does the DRB display: PCM is active on BUS?All
Ye s®Erase the DTC, if DTC resets, replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 2
2 Turn the ignition on.
With the DRB, attempt to communicate with the PCM.
Was the DRB able to communicate with the PCM?All
Ye s®Go To 3
No®Refer to the communication category and perform the appropriate
symptom.
Perform BODY VERIFICATION TEST - VER 1.
3 Turn the ignition off.
Disconnect the PCM C2 harness connector.
Connect the diagnostic junction port tester #8339 to the diagnostic junction port.
Note: Do not connect the tester to the DRB.
Measure the resistance of the PCI Bus circuit between the diagnostic junction port
tester and the PCM C2 connector.
Is the resistance below 5.0 ohms?All
Ye s®Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No®Repair the PCI Bus circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
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COMMUNICATION
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Symptom:
FCM, RADIO COMMUNICATION FAULT
When Monitored and Set Condition:
FCM, RADIO COMMUNICATION FAULT
When Monitored: With the ignition in run, and the IOD fuse installed.
Set Condition: The FCM does not receive any messages from the radio for at least 5
seconds.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE RADIO
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the Radio.
Was the DRB able to I/D or communicate with the Radio?All
Ye s®Go To 2
No®Refer to the Communication category for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRB, erase DTC's.
Cycle the ignition switch from off to on and wait approximately 1 minute.
With the DRB, read DTC's.
Did this DTC reset?All
Ye s®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
348
COMMUNICATION
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Symptom:
FCM, TCM COMMUNICATION FAULT
When Monitored and Set Condition:
FCM, TCM COMMUNICATION FAULT
When Monitored: With the ignition in run, and the IOD fuse installed.
Set Condition: The FCM does not receive any messages from the Transmission Control
Module (TCM) for at least 5 seconds.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE TCM
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the TCM.
Was the DRB able to I/D or communicate with the TCM?All
Ye s®Go To 2
No®Refer to the Communication category for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRB, erase DTC's.
Cycle the ignition switch from off to on and wait approximately 1 minute.
With the DRB, read DTC's.
Did this DTC reset?All
Ye s®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
349
COMMUNICATION
Page 386 of 4284
Symptom:
INTERNAL BCM FAILURE
When Monitored and Set Condition:
INTERNAL BCM FAILURE
When Monitored: The BCM detects an internal fault for 10 seconds.
Set Condition: The DTC will set if the BCM detects an internal fault.
POSSIBLE CAUSES
INTERNAL BCM FAILURE
TEST ACTION APPLICABILITY
1 Connect the DRB to the Data Link Connector.
Turn the ignition on.
With the DRB, erase BCM DTC's.
Turn the ignition off then turn the ignition on.
With the DRB, read BCM DTC's.
Did this DTC reset?All
Ye s®Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
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COMMUNICATION
Page 387 of 4284
Symptom:
LEFT PSD MESSAGES NOT RECEIVED
When Monitored and Set Condition:
LEFT PSD MESSAGES NOT RECEIVED
When Monitored: When the Body Control Module is awake.
Set Condition: The BCM does not sense a response from the Left Power Sliding Door
Module.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE LEFT SLIDING DOOR CONTROL MODULE
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the Left Sliding Door Control Module.
Was the DRB able to I/D or communicate with the Left Sliding Door Control Module?All
Ye s®Go To 2
No®Refer to the Communication category for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRB, erase DTC's.
Cycle the ignition switch from off to on and wait approximately 1 minute.
With the DRB, read DTC's.
Did this DTC reset?All
Ye s®Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
358
COMMUNICATION
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Symptom:
LIFTGATE MODULE MESSAGES NOT RECEIVED
When Monitored and Set Condition:
LIFTGATE MODULE MESSAGES NOT RECEIVED
When Monitored: When the Body Control Module is awake.
Set Condition: The BCM does not sense a response from the Power Liftgate Control
Module.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE POWER LIFTGATE MODULE
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the Power Liftgate Module.
Was the DRB able to I/D or communicate with the Power Liftgate Module?All
Ye s®Go To 2
No®Refer to the Communication category for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1.
2 With the DRB, erase DTC's.
Cycle the ignition switch from off to on and wait approximately 1 minute.
With the DRB, read DTC's.
Did this DTC reset?All
Ye s®Replace the Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
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COMMUNICATION