Inspection and Verification
Auxiliary Brake System - Trailer Brake Control (TBC) Module
Inspection and Verification
NOTE: Carry out all pinpoint tests without a trailer connected to the vehicle.
1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage.
Visual Inspection Chart
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
5. NOTE: The Vehicle Communication Module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM.
If the scan tool does not communicate with the VCM:
- check the VCM connection to the vehicle.
- check the scan tool connection to the VCM.
- refer to Module Communications Network Testing and Inspection, No Power To The Scan Tool, to diagnose no power to the scan tool.
6. If the scan tool does not communicate with the vehicle:
- verify the ignition is ON.
- verify the scan tool operation with a known good vehicle.
- refer to Module Communications Network Testing and Inspection, The PCM Does Not Respond To The Scan Tool, to diagnose no response from the PCM.
7. Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to Module Communications Network Testing and Inspection.
- If the network test passes, retrieve and record Continuous Memory Diagnostic Trouble Codes (CMDTCs).
8. Clear the CMDTCs and carry out the self-test diagnostics for the TBC module.
9. If the DTCs retrieved are related to the concern, go to the Trailer Brake Control (TBC) Module DTC Chart Diagnostic Trouble Code Tests and Associated Procedures. For all other DTCs, refer to Multifunction Electronic Modules Multifunction Electronic Modules.
10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures