Diagnostic Test
- VERIFY DTC IS ACTIVE NOTE:
Make sure the battery voltage is between 10 and 16 volts before proceeding.
- With the scan tool, read active DTCs.
Is this DTC active?
Yes
- Go To 2
No
- Refer to DIAGNOSIS AND TESTING and perform the STORED LOST COMMUNICATION DTCs diagnostic procedure.
- With the scan tool, read active DTCs.
- CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCS
- With the scan tool, read all active DTCs from all modules.NOTE:
Check for BCM configuration, CAN C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.
Does the scan tool display any active DTCs to the conditions listed above?
Yes
- Go to and perform the appropriate diagnostic procedure.
No
- Go To 3
- With the scan tool, read all active DTCs from all modules.
- VERIFY THE BCM IS ACTIVE ON THE BUS
- Turn the ignition on.
- With the scan tool, verify the BCM is active on the bus.
Is the BCM active on the bus?
Yes
- Go To 4
No
- Refer to DIAGNOSIS AND TESTING and perform the NO RESPONSE FROM BCM (BODY CONTROL MODULE) diagnostic procedure.
- CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCS
- With the scan tool, read all the DTCs.
Is there more than one module with active DTCs "Logged Against" the BCM?
Yes
- Replace/update the BCM in accordance with the Service Information.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 5
- With the scan tool, read all the DTCs.
- CLEAR DTC IN MODULE SETTING FAULT
- With the scan tool, select the module setting the DTC against the BCM.
- Clear active DTCs.
Is this DTC still active?
Yes
- Replace/update the module that set this DTC in accordance with the Service Information.
- Perform the appropriate VERIFICATION TEST for the module being replaced. If there is no verification test for the associated module, perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 6
- CYCLE IGNITION
- Cycle the ignition from RUN to OFF three times ending with the key in the RUN position.
Does this DTC become active?
Yes
- Go To 7
No
- The condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched and partially broken wires and the wiring harness connectors for broken, bent, pushed out and corroded terminals.
- Perform the appropriate VERIFICATION TEST for the module. If there is no verification test for the associated module, perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- Cycle the ignition from RUN to OFF three times ending with the key in the RUN position.
- CHECK FOR ADDITIONAL LOST COMMUNICATION FAULTS
- With the scan tool, view the modules.
Does the BCM and other CAN C BUS modules show Lost Communication with the remaining CAN C BUS modules?
Yes
- Go To 8
No
- Replace/update the module that set this DTC in accordance with the Service Information.
- Perform the appropriate VERIFICATION TEST for the module being replaced. If there is no verification test for the associated module, perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
- With the scan tool, view the modules.
- CHECK THE CAN C BUS (+) CIRCUIT FOR A SHORT TO VOLTAGE
- Measure the voltage between the (D65) CAN C Bus (+) circuit and ground.
Is the voltage above 5.0 volts?
Yes
- Repair the short to voltage in the CAN C Bus (+) circuit. The short to voltage is present in one of the CAN C Bus circuits. Use the Star Connectors to isolate portions of the CAN C Bus in order to locate the concern.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 9
- Measure the voltage between the (D65) CAN C Bus (+) circuit and ground.
- CHECK THE CAN C BUS (-) CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off.
- Measure the resistance between ground and the (D64) CAN C Bus (-) circuit.
Is the resistance below 10k Ohms?
Yes
- Repair the short to ground in the CAN C Bus (-) circuit. The short to ground is present in one of the CAN C Bus circuits. Use the Star Connectors to isolate portions of the CAN C Bus in order to locate the concern.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Replace/update the module that set this DTC in accordance with the Service Information.
- Perform the appropriate VERIFICATION TEST for the module being replaced. If there is no verification test for the associated module, perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .