WOMS
U code network Medium severity

U1737 U1737: "Module Communication Failure

The OBD2 code U1737 indicates a "Module Communication Failure," meaning there is a problem with communication between the vehicle's control modules, often due to a wiring issue, a faulty module, or a network problem

Definition

The OBD2 code U1737 indicates a "Module Communication Failure," meaning there is a problem with communication between the vehicle's control modules, often due to a wiring issue, a faulty module, or a network problem

Common causes

  • Faulty wiring or connectors
  • Failed control module
  • Poor ground connections
  • Corroded terminals
  • Communication network issues (e.g., CAN bus problems)
  • Software or firmware issues
  • Intermittent electrical connections
  • Low battery voltage or power supply issues

Common misdiagnoses

  • Faulty wiring or connectors
  • Defective control module
  • Software issues or updates needed
  • Battery or power supply problems
  • Grounding issues
  • Intermittent communication issues
  • Other communication protocol failures

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Sometimes, other codes can provide context or lead to the root cause of the communication failure

  2. 2. Inspect Wiring and Connectors

  3. 3. Visually inspect the wiring and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections

  4. 4. Pay special attention to the ground connections, as poor grounding can lead to communication issues

  5. 5. Check Power Supply

    Ensure that the affected modules are receiving the proper voltage. Use a multimeter to check the power supply to the modules

  6. 6. Test Communication Lines

  7. 7. Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper voltage levels

  8. 8. If you have access to an oscilloscope, you can check the signal waveforms on the communication lines to ensure they are functioning correctly

  9. 9. Inspect Modules

  10. 10. If possible, check the affected module for any signs of physical damage or water intrusion

  11. 11. If you suspect a specific module is faulty, you may need to replace it or test it in another vehicle to confirm its functionality

  12. 12. Reset the Modules

    Sometimes, resetting the modules can clear temporary communication issues. Disconnect the battery for a few minutes, then reconnect it and see if the code returns

  13. 13. Check for Software Updates

    Ensure that the vehicle's software is up to date. Sometimes, manufacturers release updates that can resolve communication issues

  14. 14. Look for Intermittent Issues

    If the problem is intermittent, try to replicate the conditions under which the code appears. This can help identify specific triggers for the communication failure

  15. 15. Consult Wiring Diagrams

    Refer to the vehicle's service manual for wiring diagrams to understand the communication network and identify any potential issues

  16. 16. Professional Diagnosis

    If the issue persists after performing these steps, it may be necessary to consult a professional technician who has experience with the specific vehicle make and model. They may have access to specialized diagnostic tools and knowledge of common issues. By following these steps, you should be able to identify and resolve the underlying cause of the U1737 code