WOMS
P code powertrain Medium severity

P067A Cylinder 4 Glow Plug Control Circuit Low

The OBD2 code P067A indicates a low voltage or malfunction in the glow plug control circuit for cylinder 4, which can affect the engine's ability to start and run efficiently in cold conditions

Definition

The OBD2 code P067A indicates a low voltage or malfunction in the glow plug control circuit for cylinder 4, which can affect the engine's ability to start and run efficiently in cold conditions

Common causes

  • Faulty glow plug
  • Damaged wiring or connectors
  • Failed glow plug control module
  • Poor ground connection
  • Short circuit in the glow plug circuit
  • Open circuit in the glow plug circuit
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Faulty glow plug
  • Bad glow plug relay
  • Wiring issues or shorts in the circuit
  • Faulty engine control module (ECM)
  • Incorrectly diagnosed fuel system issues
  • Injector problems
  • Low battery voltage or charging system issues
  • Faulty temperature sensor
  • Misdiagnosed as a compression issue
  • Ignition system problems

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues

  2. 2. Inspect the Glow Plug

    Visual Inspection: Check the glow plug for any signs of damage, corrosion, or wear. If the glow plug is faulty, it may need to be replaced

  3. 3. Resistance Test

    Use a multimeter to measure the resistance of the glow plug. A typical reading should be within the manufacturer's specifications. If it shows infinite resistance, the glow plug is likely faulty

  4. 4. Check the Glow Plug Control Module

    Inspect the glow plug control module (if equipped) for any signs of damage or corrosion. Ensure that all connections are secure

  5. 5. Test the module according to the manufacturer's specifications to ensure it is functioning correctly

  6. 6. Inspect Wiring and Connectors

    Check the wiring and connectors leading to the glow plug and the control module for any signs of damage, fraying, or corrosion

  7. 7. Look for loose connections or broken wires that could cause a low voltage reading

  8. 8. Test the Power Supply

    Use a multimeter to check for proper voltage at the glow plug connector when the ignition is turned on. You should see battery voltage (typically around 12V) when the glow plugs are activated

  9. 9. If there is no voltage, trace back to the control module or fuse to identify where the power loss is occurring

  10. 10. Check the Fuses

    Inspect the fuses related to the glow plug system. A blown fuse can interrupt the circuit and cause the P067A code

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

    If all other components check out, the issue may lie with the ECM. Ensure that the ECM is functioning correctly and is sending the proper signals to the glow plug control circuit

  12. 12. Clear Codes and Test Drive

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

  13. 13. Consult Repair Manual

    If the issue persists, consult the vehicle's repair manual for specific diagnostic procedures and specifications related to the glow plug system

  14. 14. Seek Professional Help

    If you are unable to diagnose or fix the issue, consider seeking help from a qualified mechanic or technician who has experience with diesel engines and glow plug systems. By following these steps, you should be able to identify and resolve the issue related to the P067A code