OBD-II code · Network
U0137 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.
Is it safe to drive with U0137?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyTrailer module unpowered or fuse blown
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
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
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Usually unaffected
- Parts involved
- Trailer Brake Module, Can Bus Wiring
Related codes
- U0134Lost Communication with Restraints System Sensor (Side Sensor)
- U0135Lost Communication with Parking Brake Control Module
- U0136Lost Communication with Park Brake Module B
- U0138Lost Communication with All Terrain Control Module
- U0139Lost Communication with Active Roll Control Module
- U013CLost Communication With Accelerator Pedal Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.