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U1124 Lost Communication with Vehicle Dynamics Control Module

The OBD2 code U1124 indicates that there is a loss of communication between the vehicle's control module and the Vehicle Dynamics Control Module, which may affect systems related to stability and traction control

Definition

The OBD2 code U1124 indicates that there is a loss of communication between the vehicle's control module and the Vehicle Dynamics Control Module, which may affect systems related to stability and traction control

Common causes

  • Faulty Vehicle Dynamics Control Module (VDCM)
  • Damaged or corroded wiring or connectors
  • Poor ground connection
  • Faulty communication lines (CAN bus issues)
  • Software or firmware issues in the VDCM
  • Malfunctioning sensors related to vehicle dynamics
  • Issues with the power supply to the VDCM
  • Interference from aftermarket modifications or devices

Common misdiagnoses

  • Faulty ABS module
  • Wiring issues or shorts
  • Faulty wheel speed sensors
  • Malfunctioning engine control module (ECM)
  • Incorrectly calibrated or faulty steering angle sensor
  • Battery or charging system problems
  • Faulty or corroded connectors
  • Software issues or outdated firmware in the control modules

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 the Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors related to the Vehicle Dynamics Control Module (VDCM) 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 VDCM is receiving the correct voltage. Use a multimeter to check the power supply to the module

  5. 5. Ground Connection

    Ensure that the ground connection for the VDCM is secure and functioning properly

  6. 6. Inspect the Vehicle Dynamics Control Module

    Module Condition: If possible, check the condition of the VDCM itself. Look for any signs of physical damage or water intrusion

  7. 7. Reprogramming

    In some cases, the module may need to be reprogrammed or updated with the latest software

  8. 8. Check for Communication Issues

    CAN Bus Communication: The VDCM communicates over the CAN bus. Use a scan tool to check if other modules are communicating properly. If other modules are also showing communication issues, it may indicate a problem with the CAN bus

  9. 9. Termination Resistors

    Ensure that the CAN bus termination resistors are present and functioning correctly

  10. 10. Perform a Hard Reset

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

  11. 11. Test the VDCM

    If you have access to a compatible scan tool, perform a functional test of the VDCM to see if it responds to commands

  12. 12. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the U1124 code or the VDCM for your specific vehicle make and model. Manufacturers may have specific fixes or updates

  13. 13. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with your vehicle's specific systems

  14. 14. Document Findings

    Keep a record of any tests performed, codes retrieved, and repairs made. This documentation can be helpful for future reference or if you need to consult a professional. By following these steps, you should be able to narrow down the cause of the U1124 code and take appropriate action to resolve the issue