WOMS
U code network High severity

U1028 Lost Communication with Vehicle Control Module

The OBD2 code U1028 indicates a loss of communication with the vehicle control module, suggesting that the module is not responding or is unable to communicate with other modules in the vehicle's network

Definition

The OBD2 code U1028 indicates a loss of communication with the vehicle control module, suggesting that the module is not responding or is unable to communicate with other modules in the vehicle's network

Common causes

  • Faulty Vehicle Control Module (VCM)
  • Damaged wiring or connectors
  • Poor ground connections
  • Corroded terminals
  • Faulty communication network (CAN bus issues)
  • Malfunctioning sensors or actuators
  • Software or firmware issues
  • Battery or power supply problems

Common misdiagnoses

  • Faulty wiring or connectors
  • Defective vehicle control module (VCM)
  • Malfunctioning engine control module (ECM)
  • Issues with the body control module (BCM)
  • Problems with the transmission control module (TCM)
  • Faulty sensors or actuators
  • Battery or charging system issues
  • Corrupted software or firmware in modules
  • Grounding issues
  • Intermittent communication faults

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 vehicle control module (VCM) and any other related modules

  4. 4. Look for signs of damage, corrosion, loose connections, or frayed wires

  5. 5. Ensure that all connectors are securely plugged in

  6. 6. Check Power and Ground

  7. 7. Verify that the control module is receiving the proper power supply. Use a multimeter to check voltage at the module's power and ground pins

  8. 8. Ensure that the ground connections are clean and secure

  9. 9. Test the Control Module

  10. 10. If possible, test the control module for functionality. This may involve using specialized diagnostic equipment or swapping the module with a known good one

  11. 11. Some vehicles may require reprogramming or calibration after replacing a control module

  12. 12. Inspect the CAN Bus

  13. 13. The communication between modules often occurs over a Controller Area Network (CAN) bus. Check for issues with the CAN bus wiring, such as shorts or opens

  14. 14. Use a scan tool that can monitor CAN bus communication to see if other modules are communicating properly

  15. 15. Check for Interference

  16. 16. Look for any aftermarket devices or modifications that may interfere with the vehicle's communication systems, such as alarms, remote starters, or audio systems

  17. 17. Battery and Charging System

  18. 18. Ensure that the vehicle's battery is in good condition and fully charged. A weak battery can cause communication issues

  19. 19. Check the charging system to ensure it is functioning properly

  20. 20. Clear Codes and Test Drive

  21. 21. After performing any repairs or adjustments, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  22. 22. Consult Technical Service Bulletins (TSBs)

  23. 23. Check for any manufacturer-specific TSBs related to the U1028 code or communication issues. There may be known fixes or updates available

  24. 24. Seek Professional Help

  25. 25. If the issue persists after performing these steps, consider seeking assistance from a qualified mechanic or dealership with experience in diagnosing and repairing communication issues in your specific vehicle make and model. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1028 code