WOMS
U code network High severity

U0137 Lost Communication With Trailer Brake Control Module

The OBD2 code U0137 indicates that there is a loss of communication between the vehicle's control module and the trailer brake control module, which may affect the operation of the trailer's braking system

Definition

The OBD2 code U0137 indicates that there is a loss of communication between the vehicle's control module and the trailer brake control module, which may affect the operation of the trailer's braking system

Common causes

  • Faulty trailer brake control module
  • Damaged wiring or connectors
  • Poor ground connection
  • Corroded terminals
  • Faulty vehicle communication network (CAN bus)
  • Malfunctioning vehicle ECU
  • Disconnected or loose trailer connector
  • Software issues or updates needed

Common misdiagnoses

  • Faulty Trailer Brake Control Module
  • Wiring issues or shorts in the trailer brake circuit
  • Faulty ABS module
  • Faulty vehicle speed sensor
  • Issues with the vehicle's main computer (ECM/PCM)
  • Faulty trailer connector or wiring
  • Problems with the brake system or components
  • Faulty fuses or relays related to the brake system

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Sometimes, related codes can provide more context for the issue

  2. 2. Inspect the Trailer Brake Control Module (TBCM)

    Visual Inspection: Check the TBCM for any visible damage, corrosion, or loose connections

  3. 3. Connector Check

    Ensure that the wiring harness and connectors to the TBCM are secure and free from corrosion or damage

  4. 4. Examine Wiring and Connections

    Inspect the wiring between the TBCM and the vehicle’s main computer (ECM). Look for frayed wires, broken connections, or signs of wear

  5. 5. Check for any signs of short circuits or open circuits in the wiring

  6. 6. Test the Trailer Brake Control Module

    If possible, test the TBCM with a multimeter to ensure it is receiving power and ground

  7. 7. If you have access to a known good TBCM, consider swapping it out to see if the issue persists

  8. 8. Check for Ground Issues

    Ensure that the TBCM has a good ground connection. A poor ground can lead to communication issues

  9. 9. Inspect the Vehicle’s CAN Bus

    The TBCM communicates over the Controller Area Network (CAN) bus. Check for any issues with the CAN bus wiring or other modules that may be affecting communication

  10. 10. Look for any signs of damage or disconnection in the CAN bus wiring

  11. 11. Check for Software Updates

    Sometimes, communication issues can be resolved with a software update. Check with the manufacturer for any available updates for the TBCM or the vehicle’s ECM

  12. 12. Perform a System Reset

    Disconnect the vehicle’s battery for a few minutes to reset the system. Reconnect and see if the code reappears

  13. 13. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the TBCM or communication issues for your specific vehicle make and model. Manufacturers may have issued guidance on known issues

  14. 14. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized diagnostic tools and experience with your vehicle.Conclusion By following these troubleshooting steps, you can systematically identify and address the cause of the U0137 code. Always ensure safety when working on vehicle electrical systems, and consult a professional if you are unsure about any step in the process