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P0672 Glow Plug Control Module Circuit Low

The OBD2 code P0672 indicates a low voltage or malfunction in the glow plug control module circuit for cylinder 2, which can affect the operation of the glow plug system in diesel engines

Definition

The OBD2 code P0672 indicates a low voltage or malfunction in the glow plug control module circuit for cylinder 2, which can affect the operation of the glow plug system in diesel engines

Common causes

  • Faulty glow plug
  • Bad glow plug control module
  • Open or shorted wiring in the glow plug circuit
  • Poor electrical connections
  • Blown fuse
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Faulty glow plugs
  • Bad glow plug relay
  • Wiring issues or shorts
  • Faulty engine control module (ECM)
  • Battery or charging system problems
  • Fuel system issues
  • Injector problems
  • Compression issues
  • Incorrectly diagnosed as a fuel injection timing problem
  • Misinterpretation of other related codes

Troubleshooting steps

  1. 1. Check the Code and Freeze Frame Data

    Use an OBD-II scanner to confirm the P0672 code and check for any additional codes that may provide more context

  2. 2. Review freeze frame data to understand the conditions under which the code was set

  3. 3. Inspect the Glow Plug Control Module

    Locate the glow plug control module and visually inspect it for any signs of damage, corrosion, or loose connections

  4. 4. Ensure that the module is securely mounted and that all connectors are clean and free of debris

  5. 5. Test the Glow Plugs

    Check the resistance of the glow plugs using a multimeter. A typical reading should be between 0.5 to 5 ohms, depending on the specific glow plug type

  6. 6. If any glow plug shows an open circuit (infinite resistance), it may need to be replaced

  7. 7. Check Wiring and Connectors

    Inspect the wiring harness and connectors leading to the glow plug control module and glow plugs for any signs of wear, fraying, or damage

  8. 8. Look for any loose or corroded connections that could cause a poor electrical signal

  9. 9. Test the Power Supply

    Use a multimeter to check for proper voltage at the glow plug control module. Ensure that the module is receiving the correct voltage as specified by the manufacturer

  10. 10. If the voltage is low or absent, trace the wiring back to the power source to identify any breaks or shorts

  11. 11. Check Ground Connections

    Ensure that the ground connections for the glow plug control module and glow plugs are secure and free of corrosion

  12. 12. A poor ground can lead to low voltage readings and trigger the P0672 code

  13. 13. Inspect the Engine Control Module (ECM)

    If all other components check out, the issue may lie with the ECM. Ensure that the ECM is functioning properly and that it is sending the correct signals to the glow plug control module

  14. 14. Check for any software updates or recalls related to the ECM

  15. 15. Clear the Code and Test Drive

    After performing repairs or replacements, clear the code using the OBD-II scanner

  16. 16. Take the vehicle for a test drive to see if the code reappears. Monitor the engine performance, especially during cold starts

  17. 17. Consult a Professional

    If the issue persists after following these steps, it may be necessary to consult a professional mechanic or technician who has experience with diesel engines and glow plug systems. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P0672 code. Always refer to the vehicle's service manual for specific procedures and specifications