WOMS
U code network Medium severity

U1899 U1899: "Module Communication Failure

The OBD2 code U1899 indicates a "Module Communication Failure," meaning there is a problem with communication between the vehicle's control modules, which may affect their ability to share data or function properly

Definition

The OBD2 code U1899 indicates a "Module Communication Failure," meaning there is a problem with communication between the vehicle's control modules, which may affect their ability to share data or function properly

Common causes

  • Faulty wiring or connectors
  • Failed control module
  • Poor ground connections
  • Communication network issues (CAN bus problems)
  • Corroded or damaged pins
  • 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
  • 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 other trouble codes that may be present. Sometimes, U-codes can be related to other issues that may provide more context

  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 a scope, you can check the signal quality on the communication lines

  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 consider swapping it with a known good module to see if the problem persists

  12. 12. Reset the Modules

    Sometimes, simply resetting the modules can resolve communication issues. This can be done by disconnecting the battery for a few minutes or using a scan tool to clear the codes

  13. 13. Check for Software Updates

    Verify if there are any software updates available for the vehicle's modules. Sometimes, manufacturers release updates to fix communication issues

  14. 14. Look for Intermittent Issues

    If the code 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 and communication protocols to better understand how the modules are supposed to communicate

  16. 16. Professional Diagnosis

    If the issue persists after performing these steps, it may be necessary to consult a professional technician or dealership for further diagnosis. They may have specialized tools and knowledge to pinpoint the issue. By following these steps, you should be able to identify and potentially resolve the U1899 code