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U code network Medium severity

U2873 U2873: Control Module Communication Bus Fault

The OBD2 code U2873: Control Module Communication Bus Fault indicates a communication issue between control modules in a vehicle, suggesting that one or more modules are not properly communicating over the vehicle's...

Definition

The OBD2 code U2873: Control Module Communication Bus Fault indicates a communication issue between control modules in a vehicle, suggesting that one or more modules are not properly communicating over the vehicle's data bus

Common causes

  • Faulty control module
  • Damaged wiring or connectors
  • Poor ground connections
  • Corroded terminals
  • Short circuits in the communication bus
  • Interference from aftermarket devices
  • Software issues or bugs in the control module
  • Low battery voltage or power supply issues

Common misdiagnoses

  • Faulty control module
  • Wiring issues
  • Poor ground connections
  • Corrupted software/firmware
  • Faulty sensors
  • Battery or power supply problems
  • Intermittent connection issues
  • Other communication bus faults (e.g., CAN bus issues)

Troubleshooting steps

  1. 1. Check for Additional Codes

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

  2. 2. Inspect Wiring and Connectors

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

  3. 3. Pay special attention to the communication bus wires (CAN bus) for any signs of wear or damage

  4. 4. Check for Short Circuits or Open Circuits

    Use a multimeter to check for continuity in the communication lines. Look for any short circuits or open circuits that could disrupt communication

  5. 5. Test Control Modules

    If possible, test the control modules involved in the communication bus. This may involve checking for proper operation or replacing modules if they are found to be faulty

  6. 6. Inspect Ground Connections

    Ensure that all ground connections for the control modules are secure and free of corrosion. Poor grounding can lead to communication issues

  7. 7. Check for Interference

    Look for any aftermarket devices or modifications that may interfere with the communication bus. This includes alarms, stereo systems, or other electronic devices

  8. 8. Perform a Network Test

    Some advanced scan tools can perform a network test to check the communication between modules. This can help identify which module is not communicating properly

  9. 9. Clear Codes and Test Drive

    After performing inspections and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  10. 10. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle make and model. By following these steps, you should be able to identify and resolve the underlying issue causing the U2873 code