WOMS
U code network Medium severity

U2914 U2914: Vehicle Communication Bus Malfunction

The OBD2 code U2914: Vehicle Communication Bus Malfunction indicates a problem with the communication between various control modules in the vehicle, which may affect their ability to exchange data properly

Definition

The OBD2 code U2914: Vehicle Communication Bus Malfunction indicates a problem with the communication between various control modules in the vehicle, which may affect their ability to exchange data properly

Common causes

  • Faulty wiring or connectors in the communication bus
  • Malfunctioning control modules
  • Corroded or damaged terminals
  • Poor ground connections
  • Interference from aftermarket devices
  • Software issues or bugs in the control modules
  • Low battery voltage or power supply issues

Common misdiagnoses

  • Faulty ECM (Engine Control Module)
  • Defective BCM (Body Control Module)
  • Bad wiring or connectors
  • Malfunctioning sensors
  • Issues with the CAN bus system
  • Power supply problems
  • Software glitches or updates needed
  • Faulty diagnostic tools or equipment

Troubleshooting steps

  1. 1. Check for Additional Codes

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

  2. 2. Inspect the Wiring and Connectors

    Visually inspect the wiring harnesses and connectors associated with the communication bus. Look for signs of damage, corrosion, or loose connections

  3. 3. Pay special attention to the connectors for the modules that are part of the communication network

  4. 4. Check the Communication Bus

    Use a multimeter or an oscilloscope to check the voltage levels and signal integrity on the communication bus (CAN bus, LIN bus, etc.)

  5. 5. Ensure that the bus is receiving the correct voltage and that the signals are within the expected range

  6. 6. Test the Modules

    Identify the modules that are part of the communication network and test them individually. This may involve checking for proper operation or communication with a scan tool

  7. 7. If a specific module is not responding, it may need to be replaced or reprogrammed

  8. 8. Inspect for Short Circuits or Open Circuits

    Check for any short circuits or open circuits in the wiring that could disrupt communication. This may involve tracing the wiring and using a multimeter to test continuity

  9. 9. Check for Ground Issues

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

  10. 10. Look for Interference

    Investigate if there are any aftermarket devices or modifications that could be interfering with the communication bus. This includes alarms, stereo systems, or other electronic devices

  11. 11. Perform a Hard Reset

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

  12. 12. Update or Reprogram Modules

    If the vehicle has had recent software updates or module replacements, ensure that all modules are properly updated and programmed to communicate with each other

  13. 13. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on known issues related to communication bus malfunctions.1

  14. 14. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or dealership with specialized diagnostic equipment. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U2914 code