Inspection and Verification

Inspection and Verification
1. Verify the TBC is factory installed by checking that the vehicle is equipped with a brake pressure transducer on the master cylinder.
2. Verify the customer concern.

3. NOTE: The TBC does not function with electric-over-hydraulic or surge trailer brake types.

Verify that the trailer brakes are electric-actuated drum type brakes.
4. Verify the stoplamps operate correctly by applying and releasing the brake pedal with the ignition switch in the OFF position and the trailer disconnected.
If the stoplamps operate correctly, proceed to the next step.
5. Visually inspect for obvious signs of mechanical or electrical damage.




Visual Inspection Chart

6. If the cause is not visually evident, connect the diagnostic tool to the data link connector (DLC) and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
^ check that the program card is correctly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.
7. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating information.
8. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
^ CAN, ISO, or UBP circuit fault; all electronic control units no response/not equipped, refer to Information Bus (Module Communications Network).
^ No response/not equipped for the TBC, GO to Pinpoint Test A. Test A: No Communication With the Trailer Brake Controller (TBC)
^ System passed, retrieve and record the continuous diagnostic trouble codes (DTC's), erase the continuous DTC's, and carry out self-test diagnostics for the TBC and the anti-lock brake system (ABS) module.
9. If the DTC's retrieved are related to the concern, go to the Trailer Brake Controller (TBC) Diagnostic Trouble Code (DTC) Index or Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index to continue diagnosis. Trailer Brake Controller (TBC) Diagnostic Trouble Code (DTC) Index Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index
10. If no DTC's related to the concern are retrieved, GO to Symptom Chart to continue diagnosis. Diagnosis By Symptom - Auxiliary Brake System