WOMS
U code network High severity

U0143 Lost Communication With Body Control Module "C

The OBD2 code U0143 indicates a loss of communication with the Body Control Module "C," which may affect various electrical systems in the vehicle

Definition

The OBD2 code U0143 indicates a loss of communication with the Body Control Module "C," which may affect various electrical systems in the vehicle

Common causes

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

Common misdiagnoses

  • Faulty Body Control Module (BCM)
  • Wiring issues or damaged connectors
  • Faulty Instrument Cluster
  • Faulty Engine Control Module (ECM)
  • Battery or charging system problems
  • Faulty CAN bus communication
  • Corroded or loose ground connections
  • Faulty or incompatible aftermarket accessories

Troubleshooting steps

  1. 1. Check for Other Codes

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

  2. 2. Inspect Wiring and Connectors

    Visual Inspection: Check the wiring and connectors related to the Body Control Module (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. Inspect the Body Control Module

    Physical Condition: Check the BCM for any signs of physical damage or water intrusion

  7. 7. Reprogramming

    If the BCM has been replaced, ensure that it has been properly programmed and configured for the vehicle

  8. 8. Test Communication Lines

    CAN Bus: Use a scan tool to check the communication on the CAN bus. If other modules are not communicating, there may be a fault in the bus itself

  9. 9. Scope Testing

    If available, use an oscilloscope to check for proper signal patterns on the communication lines

  10. 10. Check for Intermittent Issues

    Temperature Sensitivity: Sometimes, issues can be temperature-related. Check if the problem occurs only under certain conditions (e.g., after the vehicle has been running for a while)

  11. 11. Wiggle Test

    While monitoring the communication, gently wiggle the wiring harnesses to see if the communication is restored

  12. 12. Inspect Related Modules

    Other Modules: Check if other modules that communicate with the BCM are functioning properly. A fault in another module can sometimes cause communication issues

  13. 13. Clear Codes and Test Drive

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

  14. 14. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have known issues and recommended fixes

  15. 15. Professional Diagnosis

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis. They may have specialized tools and knowledge to address complex issues. By following these steps, you should be able to identify the root cause of the U0143 code and take appropriate action to resolve it