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U2959Lost Communication with Vehicle Control Module

The OBD2 code U2959 indicates a loss of communication with the vehicle control module, suggesting that the module is not responding or is unable to communicate with other systems in the vehicle

Definition

The OBD2 code U2959 indicates a loss of communication with the vehicle control module, suggesting that the module is not responding or is unable to communicate with other systems in the vehicle

Common causes

  • Faulty wiring or connectors
  • Failed Vehicle Control Module (VCM)
  • Corroded or damaged connectors
  • Poor ground connections
  • Malfunctioning communication network (CAN bus)
  • Software issues or bugs in the VCM
  • Interference from aftermarket devices
  • Low battery voltage or power supply issues

Common misdiagnoses

  • Faulty Vehicle Control Module (VCM)
  • Wiring issues or shorts in the communication lines
  • Faulty connectors or terminals
  • Issues with other control modules (e.g., Engine Control Module, Transmission Control Module)
  • Battery or power supply problems
  • Corrupted software or firmware in the control modules
  • Faulty sensors that affect communication
  • Grounding issues in the electrical system

Troubleshooting steps

  1. 1.Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Other codes may provide more context or indicate related issues

  2. 2.Inspect Wiring and Connectors

  3. 3.Visually inspect the wiring and connectors associated with the affected control module. Look for signs of damage, corrosion, or loose connections

  4. 4.Pay special attention to the wiring harnesses that connect to the control modules

  5. 5.Check Power and Ground

  6. 6.Ensure that the control module has proper power and ground connections. Use a multimeter to check for voltage at the module's power supply pins and continuity at the ground pins

  7. 7.If there is no power or ground, trace the wiring back to the fuse box or battery to identify the issue

  8. 8.Test the Control Module

  9. 9.If possible, test the control module itself. This may involve using a scan tool to communicate with the module or swapping it with a known good module if available

  10. 10.Ensure that the module is functioning correctly and is not damaged

  11. 11.Check for Communication Issues

  12. 12.Use a scan tool to check if other modules in the vehicle can communicate. If other modules are also unresponsive, it may indicate a network issue

  13. 13.Inspect the CAN (Controller Area Network) bus wiring for shorts, opens, or interference

  14. 14.Inspect Fuses

  15. 15.Check the fuses related to the control modules and communication systems. Replace any blown fuses and retest

  16. 16.Look for Software Updates

  17. 17.Check if there are any software updates available for the vehicle's control modules. Sometimes, communication issues can be resolved with a software update

  18. 18.Perform a Hard Reset

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

  20. 20.Consult Technical Service Bulletins (TSBs)

  21. 21.Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on known communication issues

  22. 22.Seek Professional Help

  23. 23.If the issue persists after performing the above steps, consider seeking assistance from a qualified technician or automotive professional who has experience with the specific vehicle and its systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U2959 code