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U014B Lost Communication with Body Control Module (BCM) 'A'

The OBD2 code U014B indicates that there is a loss of communication with the Body Control Module (BCM) 'A', which may affect various electrical systems in the vehicle

Definition

The OBD2 code U014B indicates that there is a loss of communication with the Body Control Module (BCM) 'A', which may affect various electrical systems in the vehicle

Common causes

  • Faulty Body Control Module (BCM)
  • Damaged wiring or connectors
  • Corroded terminals
  • Poor ground connection
  • Faulty communication network (CAN bus)
  • Blown fuses
  • Software issues or programming errors
  • Intermittent electrical connections

Common misdiagnoses

  • Faulty Body Control Module (BCM)
  • Wiring issues or shorts in the communication lines
  • Faulty Engine Control Module (ECM)
  • Corrupted software or firmware in the BCM
  • Issues with other control modules (e.g., ABS, airbag)
  • Battery or power supply problems
  • Poor ground connections
  • Faulty connectors or terminals
  • Intermittent communication issues due to environmental factors
  • Incorrectly configured aftermarket accessories or modifications

Troubleshooting steps

  1. 1. Check for Additional Codes

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

  2. 2. Inspect Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors related to the BCM 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 pushed back

  4. 4. Check Power and Ground

    Power Supply: Verify that the BCM is receiving the correct voltage. Use a multimeter to check the power supply to the module

  5. 5. Ground Connections

    Ensure that the ground connections for the BCM are secure and free of corrosion

  6. 6. Test the Body Control Module

    If possible, test the BCM itself. This may involve using a scan tool to check for communication with the module

  7. 7. If you have access to a known good BCM, you can swap it out to see if the issue persists

  8. 8. Inspect Related Modules

    Check for communication issues with other modules in the vehicle. Sometimes, a fault in another module can cause communication problems with the BCM

  9. 9. Check for Short Circuits

    Inspect the wiring for any short circuits that may be affecting communication. This can include checking for shorts to ground or power

  10. 10. Look for Software Issues

    Ensure that the vehicle’s software is up to date. Sometimes, a software update can resolve communication issues

  11. 11. Perform a Network Test

    Use a scan tool to perform a network test to see if other modules are communicating properly. This can help identify if the issue is isolated to the BCM or if it’s a broader communication problem

  12. 12. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns

  13. 13. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with automotive electronics and can perform more advanced diagnostics. By following these steps, you should be able to identify the cause of the U014B code and take appropriate action to resolve the issue