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U code network High severity

U2990 Lost Communication with Vehicle Control Module

The OBD2 code U2990 indicates a loss of communication with a specific vehicle control module, suggesting that the module is not responding or is unable to communicate with the vehicle's network

Definition

The OBD2 code U2990 indicates a loss of communication with a specific vehicle control module, suggesting that the module is not responding or is unable to communicate with the vehicle's network

Common causes

  • Faulty Vehicle Control Module (VCM)
  • Damaged wiring or connectors
  • Poor ground connections
  • Corrupted software or firmware
  • Faulty communication network (CAN bus issues)
  • Low battery voltage
  • Intermittent electrical connections
  • Malfunctioning sensors or actuators

Common misdiagnoses

  • Faulty wiring or connectors
  • Defective vehicle control module (VCM)
  • Issues with the powertrain control module (PCM)
  • Malfunctioning body control module (BCM)
  • Problems with the engine control module (ECM)
  • Faulty sensors or actuators
  • Battery or charging system issues
  • Software or firmware glitches
  • Grounding issues
  • Communication network failures (CAN bus issues)

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Sometimes, U2990 may be accompanied by other codes that 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 Control Module (VCM) 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

    Power Supply: Verify that the VCM is receiving the correct voltage. Use a multimeter to check the power supply to the module

  5. 5. Ground Connections

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

  6. 6. Inspect the Vehicle Control Module

    Module Condition: Check the VCM for any physical damage or signs of water intrusion

  7. 7. Reprogramming

    If the module is suspected to be faulty, consider reprogramming or updating the software if applicable

  8. 8. Check for Communication Issues

    CAN Bus Communication: Use a scan tool to check if other modules in the vehicle are communicating properly. If other modules are also not communicating, there may be a problem with the CAN bus

  9. 9. Network Integrity

    Inspect the CAN bus wiring for shorts, opens, or other issues

  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 VCM

    If possible, test the VCM in another vehicle of the same make and model to determine if the module itself is faulty

  12. 12. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to U2990

  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 and its systems.Conclusion Troubleshooting OBD-II code U2990 involves a systematic approach to check for communication issues, inspect wiring and connections, and verify the functionality of the Vehicle Control Module. Always ensure safety precautions are taken when working on vehicle electronics