Page 367 of 4284
Symptom:
ATC MESSAGES NOT RECEIVED
When Monitored and Set Condition:
ATC MESSAGES NOT RECEIVED
When Monitored: With the ignition in run, and the IOD fuse installed.
Set Condition: The BCM does not receive any messages from the Automatic Temperature
Control (ATC) module for at least 0.125 seconds.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE AUTOMATIC TEMPERATURE CONTROL MODULE
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, enter Body then Automatic Temp Control.
Was the DRB able to I/D or communicate with 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 Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
338
COMMUNICATION
Page 368 of 4284
Symptom:
AUDIO MESSAGES NOT RECEIVED
When Monitored and Set Condition:
AUDIO MESSAGES NOT RECEIVED
When Monitored: With the ignition in run, and the IOD fuse installed.
Set Condition: The BCM does not receive any messages from the radio for at least 5
seconds.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE RADIO
BODY 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 Body Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
339
COMMUNICATION
Page 372 of 4284
Symptom:
FCM MESSAGES NOT RECEIVED
When Monitored and Set Condition:
FCM MESSAGES NOT RECEIVED
When Monitored: With the ignition in run, and the IOD fuse installed.
Set Condition: The BCM does not receive any messages from the Front Control Module
(FCM) for at least 5 seconds.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE FRONT CONTROL MODULE
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the FCM.
Was the DRB able to I/D or communicate with the FCM?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.
343
COMMUNICATION
Page 373 of 4284
Symptom:
FCM, BCM COMMUNICATION FAULT
When Monitored and Set Condition:
FCM, BCM 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 Body Control Module
(BCM) for at least 5 seconds.
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH THE BCM
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the BCM.
Was the DRB able to I/D or communicate with the BCM?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.
344
COMMUNICATION
Page 374 of 4284

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
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.
347
COMMUNICATION
Page 377 of 4284
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
Page 378 of 4284
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