Lost Communication with Trailer Brake Control Module
The vehicle network has lost the integrated trailer brake controller. Trailer braking falls back to passive operation; trailer-related warnings appear in the cluster.
Affected components
- Trailer brake module
- Can bus wiring
Common causes
- High likelihood: Trailer module unpowered or fuse blown
- Low likelihood: Gateway module routing CAN messages incorrectly
- Low likelihood: CAN terminating resistor (120 Ω) drifted out of spec
Possible symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Diagnostic notes
- The malfunction indicator lamp may illuminate
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.