WOMS
U code network High severity

U1055 Lost Communication with Vehicle Control Module

The OBD2 code U1055 indicates that there is a loss of communication with the vehicle control module, meaning the module is not responding or cannot be reached by the diagnostic tool

Definition

The OBD2 code U1055 indicates that there is a loss of communication with the vehicle control module, meaning the module is not responding or cannot be reached by the diagnostic tool

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 modules
  • Software or firmware issues
  • Battery or power supply problems

Common misdiagnoses

  • Faulty Vehicle Control Module (VCM)
  • Wiring issues or damaged connectors
  • Faulty or corroded ground connections
  • Malfunctioning power supply to the VCM
  • Issues with other control modules
  • Software or firmware issues
  • Faulty diagnostic tools or procedures
  • Battery or charging system problems

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 the Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors associated with the affected control module 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 damaged

  4. 4. Check Power and Ground

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

  5. 5. Test the Control Module

    If possible, test the control module itself. This may involve using a known good module or performing a bench test if applicable

  6. 6. Inspect for Communication Issues

    CAN Bus: If the vehicle uses a Controller Area Network (CAN) bus, check for issues with the bus itself. Look for short circuits, open circuits, or other faults in the wiring

  7. 7. Termination Resistors

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

  8. 8. Check for Software Updates

    Sometimes, a software update for the control module can resolve communication issues. Check with the manufacturer for any available updates

  9. 9. Perform a Hard Reset

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

  10. 10. Scan Tool Compatibility

    Ensure that the OBD-II scanner being used is compatible with the vehicle. Some vehicles may require specific tools for proper communication

  11. 11. Look for Environmental Factors

    Check for any environmental factors that may affect communication, such as moisture or extreme temperatures

  12. 12. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to U1055.1

  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 the specific vehicle make and model. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1055 code