WOMS
U code network High severity

U021E U021E: "BECM Communication Failure

The OBD2 code U021E indicates a communication failure between the vehicle's Body Control Module (BCM) and other control modules, suggesting a problem with data exchange or connectivity

Definition

The OBD2 code U021E indicates a communication failure between the vehicle's Body Control Module (BCM) and other control modules, suggesting a problem with data exchange or connectivity

Common causes

  • Faulty Body Control Module (BCM)
  • Damaged wiring or connectors
  • Poor ground connections
  • Corroded terminals
  • Software issues or bugs
  • Faulty communication network (CAN bus)
  • Intermittent electrical connections
  • Low battery voltage or power supply issues

Common misdiagnoses

  • Faulty Body Control Module (BCM)
  • Wiring issues or shorts in the communication lines
  • Defective or corroded connectors
  • Malfunctioning Engine Control Module (ECM)
  • Issues with the Powertrain Control Module (PCM)
  • Battery or charging system problems
  • Software or firmware issues in the modules
  • Faulty sensors related to the communication network

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues present

  2. 2. Inspect Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors associated with the BECM for any signs of damage, corrosion, or loose connections

  3. 3. Connector Pins

    Ensure that the pins in the connectors are not bent, corroded, or damaged

  4. 4. Check Power and Ground

    Verify that the BECM is receiving the proper power supply and ground. Use a multimeter to check voltage at the BECM connector

  5. 5. Ensure that the ground connections are clean and secure

  6. 6. Test the BECM

    If possible, perform a functional test of the BECM. This may require specialized diagnostic equipment or software

  7. 7. If the BECM is suspected to be faulty, consider replacing it or reprogramming it if necessary

  8. 8. Inspect Other Modules

    Since communication issues can be caused by other modules, check the functionality of other related control modules (e.g., PCM, BCM)

  9. 9. Look for any signs of failure or communication issues in these modules

  10. 10. Check for Short Circuits or Open Circuits

    Use a multimeter to check for short circuits or open circuits in the communication lines (CAN bus) between the BECM and other modules

  11. 11. Inspect the CAN Bus

    If your vehicle uses a CAN bus system, check for issues with the bus itself. Look for any damaged wiring or poor connections that could affect communication

  12. 12. Use a CAN bus diagnostic tool to monitor the communication and check for errors

  13. 13. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner

  14. 14. Take the vehicle for a test drive to see if the code reappears

  15. 15. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the BECM or communication issues for your specific vehicle make and model. Manufacturers may have specific fixes or updates

  16. 16. Seek Professional Help

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing and repairing communication issues. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U021E code