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P231C Ignition Coil 'D' Secondary Circuit High

The OBD2 code P231C indicates that there is a high voltage detected in the secondary circuit of ignition coil 'D', which may suggest a malfunction in the ignition coil, wiring, or related components

Definition

The OBD2 code P231C indicates that there is a high voltage detected in the secondary circuit of ignition coil 'D', which may suggest a malfunction in the ignition coil, wiring, or related components

Common causes

  • Faulty ignition coil 'D'
  • Open or shorted wiring in the ignition coil circuit
  • Poor electrical connections or corroded terminals
  • Faulty engine control module (ECM)
  • High resistance in the ignition coil circuit
  • Faulty spark plug or spark plug gap issues
  • Issues with the ignition coil driver circuit in the ECM

Common misdiagnoses

  • Faulty ignition coil
  • Bad spark plugs
  • Wiring issues or shorts
  • Faulty engine control module (ECM)
  • Fuel delivery problems
  • Vacuum leaks
  • Incorrectly installed ignition components
  • Faulty crankshaft or camshaft position sensors

Troubleshooting steps

  1. 1. Check for Additional Codes

    Before proceeding, check for any other related trouble codes that may provide more context to the issue

  2. 2. Visual Inspection

  3. 3. Inspect the ignition coil 'D' and its wiring for any visible damage, such as frayed wires, corrosion, or loose connections

  4. 4. Check the connectors for signs of wear, dirt, or moisture

  5. 5. Test the Ignition Coil

  6. 6. Use a multimeter to measure the resistance of the ignition coil. Compare the readings to the specifications provided in the vehicle's service manual

  7. 7. If the resistance is outside the specified range, the ignition coil may be faulty and should be replaced

  8. 8. Check the Power and Ground

  9. 9. Verify that the ignition coil is receiving the correct voltage. Use a multimeter to check for power at the ignition coil connector while the engine is running

  10. 10. Ensure that the ground connection for the ignition coil is solid and free of corrosion

  11. 11. Inspect the Spark Plug

  12. 12. Remove the spark plug associated with ignition coil 'D' and inspect it for wear or damage. A fouled or damaged spark plug can cause ignition issues

  13. 13. Replace the spark plug if necessary

  14. 14. Check for Short Circuits

  15. 15. Inspect the wiring harness for any signs of short circuits or grounding issues that could cause high voltage readings in the secondary circuit

  16. 16. Test the Engine Control Module (ECM)

  17. 17. If all other components check out, the issue may lie with the ECM. Use a scan tool to check for any software updates or faults in the ECM

  18. 18. In some cases, reprogramming or replacing the ECM may be necessary

  19. 19. Clear the Codes and Test Drive

  20. 20. After performing repairs or replacements, clear the trouble codes using an OBD-II scanner

  21. 21. Take the vehicle for a test drive to see if the code returns

  22. 22. Consult a Professional

    If the issue persists after following these steps, it may be best to consult a professional mechanic for further diagnosis. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P231C code