WOMS
U code network High severity

U1660 Lost Communication with Body Control Module (BCM)

The OBD2 code U1660 indicates a loss of communication between the vehicle's control module and the Body Control Module (BCM), which can affect various electrical systems and functions

Definition

The OBD2 code U1660 indicates a loss of communication between the vehicle's control module and the Body Control Module (BCM), which can affect various electrical systems and functions

Common causes

  • Faulty Body Control Module (BCM)
  • Damaged wiring or connectors
  • Corroded terminals
  • Poor ground connection
  • 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 shorts in the communication lines
  • Faulty or corroded connectors
  • Issues with the Powertrain Control Module (PCM)
  • Malfunctioning Instrument Cluster
  • Battery or charging system problems
  • Faulty sensors or actuators related to the BCM
  • Software or firmware issues in the BCM or other modules

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 BCM

  5. 5. Ground Connections

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

  6. 6. Inspect the BCM

    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 to 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 Short Circuits

    Inspect the wiring for any short circuits to ground or power that could affect communication with the BCM

  11. 11. Look for Environmental Factors

    Check for any environmental factors that could affect the BCM, such as moisture or extreme temperatures

  12. 12. Perform a Hard Reset

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

  13. 13. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the U1660 code for your specific vehicle make and model. Manufacturers may have known fixes or updates

  14. 14. Replace the BCM (if necessary)

    If all other steps fail and the BCM is determined to be faulty, consider replacing it. Ensure proper programming and configuration after replacement.1

  15. 15. Seek Professional Help

    If you are unable to resolve the issue, it may be best to consult a professional mechanic or automotive technician who has experience with your vehicle's make and model. By following these steps, you should be able to identify the cause of the U1660 code and take appropriate action to resolve the communication issue with the Body Control Module