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P code powertrain High severity

P0655 Malfunction Indicator Lamp (MIL) Control Circuit Short to Ground

The OBD2 code P0655 indicates a malfunction in the Malfunction Indicator Lamp (MIL) control circuit, specifically a short to ground, which means there is an electrical issue causing the MIL to not function properly

Definition

The OBD2 code P0655 indicates a malfunction in the Malfunction Indicator Lamp (MIL) control circuit, specifically a short to ground, which means there is an electrical issue causing the MIL to not function properly

Common causes

  • Shorted wiring or connectors in the MIL circuit
  • Faulty Engine Control Module (ECM)
  • Damaged or corroded ground connections
  • Failed MIL bulb or LED
  • Faulty relay or control circuit components
  • Poor connections or loose wiring in the circuit
  • Aftermarket modifications or installations affecting the circuit

Common misdiagnoses

  • Faulty Engine Control Module (ECM)
  • Wiring issues or shorts in the harness
  • Faulty Malfunction Indicator Lamp (MIL)
  • Issues with other related sensors
  • Faulty ignition switch
  • Problems with the vehicle's body control module (BCM)
  • Incorrectly installed aftermarket accessories or modifications

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues

  2. 2. Inspect the MIL Bulb

    Ensure that the MIL bulb is functioning properly. If the bulb is burned out or missing, it can cause the circuit to behave unexpectedly

  3. 3. Visual Inspection of Wiring and Connectors

  4. 4. Inspect the wiring and connectors associated with the MIL control circuit for any signs of damage, corrosion, or loose connections

  5. 5. Look for frayed wires, broken connectors, or any signs of wear that could lead to a short to ground

  6. 6. Check for Shorts to Ground

  7. 7. Use a multimeter to check for continuity between the MIL control circuit and ground. If there is continuity, it indicates a short to ground

  8. 8. Trace the wiring back to the ECM and check for any points where the wire may be pinched or damaged

  9. 9. Test the MIL Control Circuit

  10. 10. With the ignition on (engine off), use a multimeter to measure the voltage at the MIL control circuit. It should typically show battery voltage

  11. 11. If there is no voltage or it is significantly lower than expected, further investigation into the circuit is needed

  12. 12. Inspect the ECM

  13. 13. If the wiring and connectors are in good condition, the issue may lie within the ECM itself. Check for any signs of damage or water intrusion

  14. 14. If necessary, consult the vehicle's service manual for specific testing procedures for the ECM

  15. 15. Repair or Replace Faulty Components

  16. 16. Based on the findings from the above steps, repair any damaged wiring or connectors

  17. 17. If the MIL bulb is faulty, replace it

  18. 18. If the ECM is determined to be faulty, it may need to be reprogrammed or replaced

  19. 19. Clear the Codes and Test Drive

    After making repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  20. 20. Monitor for Recurrence

    After the test drive, monitor the vehicle for any signs of the MIL illuminating again or any other related issues. If the problem persists after following these steps, it may be advisable to consult a professional mechanic or technician for further diagnosis and repair