U0137: Lost Communication with Trailer Brake Control Module

Introduction

The DTC U0137 error code indicates a communication problem between the vehicle's electronic control unit (ECU) and the trailer brake control module. This type of error can significantly affect the safety of the vehicle, especially when driving with a trailer. Understanding the symptoms, causes, and possible solutions to this error is essential for every auto mechanic. In this article, we will analyze the DTC U0137 code in detail and provide practical guidance for diagnosis and repair.

Symptoms

Symptoms associated with the U0137 error code can vary, but some of the most common include:

  • Illumination of the warning light in the dashboard, often identified as the brake light or general warning light.

  • Malfunctions of the trailer braking system, such as failure to apply the brakes or slow response.

  • Error messages displayed in the vehicle diagnostic system.

  • Loss of functionality of trailer assist features, such as stability control or brake assist.

Cause

The causes of the DTC code U0137 can be variable and may include:

  • Wiring problems :
    Cracks, short circuits or breaks in the wires connecting the ECU to the trailer brake control module can interrupt communication.

  • ECU malfunction :
    An internal fault in the ECU may prevent signals from being sent or received correctly.

  • Faulty trailer brake control module :
    If the module itself is faulty or damaged, it will not be able to communicate properly.

  • Power problems :
    Inadequate power supply to the brake control module may cause loss of communication.

Diagnosis

Diagnosing a U0137 error code requires a systematic approach. Here are the steps to follow:

  1. Vehicle Scan :
    Use an OBD-II scanner to confirm the presence of DTC U0137 and to look for any related codes, such as U0140 (Lost Communication with ABS Control Module) or U0141 (Lost Communication with Traction Control Module).

  2. Visual inspection :
    Inspect the wires and connections between the ECU and the trailer brake control module for visible damage, corrosion, or loose connections.

  3. Continuity test :
    Use a multimeter to test the continuity of the wires and to make sure there are no breaks in the circuit.

  4. Power Check :
    Check that the brake control module receives the correct supply voltage.

  5. Module Test :
    If all of the above steps reveal no problems, use a diagnostic test to verify the operation of the brake control module.

Resolution and repair

Once the cause of the U0137 error code has been identified, the following procedures can be adopted:

  • Cable Repair :
    If any damaged cables are found, they should be repaired or replaced.

  • Replacing the ECU :
    If the ECU is found to be faulty, it will need to be replaced with a new unit, making sure to program the new ECU for the specific vehicle.

  • Replacing the brake control module :
    If the control module malfunctions, it will need to be replaced.

  • Power Check :
    If you experience power problems, correct the problem so that the control module receives the correct voltage.

Once the repair is complete, it is important to clear the DTC codes from the ECU memory and retest the system to ensure the fault has been resolved.

Insight into the components involved

Mechanical and Electrical Components Related to DTC Code U0137

The DTC code U0137 involves several critical components of the braking system:

  • ECU (Electric Control Unit) :
    Handles communications and commands to various modules, including the trailer brake control module.

  • Trailer Brake Control Module :
    Regulates the operation of the trailer brakes based on the signals received from the ECU.

  • Wiring :
    Includes the cables and electrical connectivity between the ECU and the control module, which are essential for proper communication.

  • Brake sensors :
    They monitor braking conditions and send information to the ECU, influencing the system.

Conclusions

The DTC U0137 error code represents a serious communication problem that can compromise the safety of your vehicle and trailer. Accurate diagnosis and timely repair are essential to ensure the proper functioning of your braking system. Auto mechanics must stay up to date with modern vehicle communication technologies and schemes to effectively address these issues. With proper diagnosis and repair, your vehicle can be restored to safety and reliability.

Important
Not all OBD2 codes used by one manufacturer are used by other brands, and may not have the same meaning.
The information presented here is for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any concerns about repairing your vehicle, please contact your repair shop.