U0137: Lost Communication With Trailer Brake Control Module
What does U0137 mean?
U0137 is a diagnostic trouble code indicating "Lost Communication With Trailer Brake Control Module". The vehicle's main computer has lost its ability to communicate with a specific module over the data bus. This could be caused by a wiring fault, a blown fuse, or a failed control module.
Symptoms you may notice
- Check engine light (MIL) illuminated on dashboard
- ABS warning light on
- Brake pedal feels different
- Unusual braking behaviour
Estimated repair cost
Typical range in Australia (parts + labour)
Common causes
- Failed control module
- CAN bus wiring fault or short
- Blown fuse to the affected module
- Water intrusion in a connector or module
- Battery voltage too low
What should you do?
This code sits in the braking system. Your normal hydraulic brakes generally still work, but the electronics layered on top of them, ABS, EBD and emergency brake assist, can drop out. You will not notice until you brake hard or brake on a wet or loose surface, and that is the moment they would have helped. Treat the car as needing a workshop rather than as safe to drive, and get it looked at before your next real trip.
Get a diagnosis for YOUR car
Code U0137 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.