WOMS
U code network Medium severity

U1550 U1550: "BCM Communication Failure

The OBD2 code U1550 indicates a "BCM Communication Failure," meaning there is a problem with the communication between the Body Control Module (BCM) and other modules in the vehicle's network

Definition

The OBD2 code U1550 indicates a "BCM Communication Failure," meaning there is a problem with the communication between the Body Control Module (BCM) and other modules in the vehicle's network

Common causes

  • Faulty Body Control Module (BCM)
  • Poor or damaged wiring/connectors
  • Corroded terminals
  • Failed or malfunctioning sensors
  • Software issues or programming errors
  • Low battery voltage
  • Intermittent electrical connections
  • Faulty communication network (CAN bus issues)

Common misdiagnoses

  • Faulty Body Control Module (BCM)
  • Wiring issues or shorts in the communication lines
  • Defective or corroded connectors
  • Malfunctioning other control modules (e.g., PCM, ECM)
  • Battery or power supply issues
  • Software or firmware glitches
  • Grounding problems
  • Faulty sensors or actuators related to the BCM

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Other codes can provide additional context for the issue

  2. 2. Inspect Wiring and Connectors

    Visual Inspection: Check the wiring harnesses 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 or corroded

  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 BCM

  5. 5. Ground Connections

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

  6. 6. Test the BCM

    If possible, test the BCM using a scan tool that can communicate with it. Check for any response or data from the BCM

  7. 7. If the BCM is not responding, it may be faulty and require replacement

  8. 8. Inspect Other Modules

    Since the BCM communicates with other modules, check for communication issues with those modules as well. This includes modules like the Engine Control Module (ECM), Transmission Control Module (TCM), and others

  9. 9. Use a scan tool to see if other modules are reporting communication issues

  10. 10. Check for Short Circuits

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

  11. 11. Look for Software Issues

    Sometimes, a software update may be required for the BCM or other modules. Check with the manufacturer for any available updates

  12. 12. Perform a Hard Reset

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

  13. 13. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the U1550 code for your specific vehicle make and model. Manufacturers may have specific fixes or recommendations

  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 for further diagnosis and repair.Conclusion Troubleshooting a U1550 code can involve a combination of electrical diagnostics, module testing, and sometimes software updates. Always refer to the vehicle's service manual for specific procedures and specifications related to your vehicle