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U code network High severity

U0115 Lost Communication With ECM/PCM "B

The OBD2 code U0115 indicates a loss of communication with the Engine Control Module (ECM) or Powertrain Control Module (PCM) "B," which may affect vehicle performance and diagnostics

Definition

The OBD2 code U0115 indicates a loss of communication with the Engine Control Module (ECM) or Powertrain Control Module (PCM) "B," which may affect vehicle performance and diagnostics

Common causes

  • Faulty ECM/PCM
  • Wiring issues (damaged, corroded, or loose connections)
  • Faulty communication network (CAN bus issues)
  • Malfunctioning sensors or modules
  • Software or firmware issues
  • Power supply problems to the ECM/PCM
  • Grounding issues
  • Aftermarket modifications or installations affecting communication

Common misdiagnoses

  • Faulty wiring or connectors
  • Bad ECM/PCM
  • Faulty sensors
  • Corrupted software or firmware
  • Issues with the CAN bus
  • Power supply problems
  • Grounding issues
  • Faulty transmission control module (TCM)

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 ECM/PCM 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 pushed back

  4. 4. Check Power and Ground

    Power Supply: Verify that the ECM/PCM 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 ECM/PCM are secure and free of corrosion

  6. 6. Inspect the ECM/PCM

    Module Condition: Check for any physical damage to the ECM/PCM, such as cracks or water intrusion

  7. 7. Reprogramming

    If the module has been recently replaced or reprogrammed, ensure that it has been done correctly

  8. 8. Check for Communication Issues

    CAN Bus: If your vehicle uses a Controller Area Network (CAN) bus, check for communication issues on the bus. Use a scan tool to monitor the data from other modules

  9. 9. Other Modules

    Ensure that other modules in the vehicle are functioning correctly, as a failure in one module can affect communication

  10. 10. Test the OBD-II Port

    Connection: Ensure that the OBD-II port is functioning properly and that the scanner can communicate with other modules

  11. 11. Wiring

    Inspect the wiring from the OBD-II port to the ECM/PCM for any damage

  12. 12. Perform a Hard Reset

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

  13. 13. Check for Software Updates

    Verify if there are any software updates available for the ECM/PCM that may address communication issues

  14. 14. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to your vehicle make and model that may address known issues with the ECM/PCM communication

  15. 15. 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 specific vehicle make and model. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U0115 code