WOMS
P code powertrain Medium severity

P068E Cylinder 8 Glow Plug Control Circuit Low

The OBD2 code P068E indicates a low voltage or malfunction in the glow plug control circuit for cylinder 8, which can affect the glow plug's ability to heat properly for cold starting in diesel engines

Definition

The OBD2 code P068E indicates a low voltage or malfunction in the glow plug control circuit for cylinder 8, which can affect the glow plug's ability to heat properly for cold starting in diesel engines

Common causes

  • Faulty glow plug
  • Open or shorted wiring in the glow plug circuit
  • Bad glow plug control module
  • Poor electrical connections
  • Blown fuse
  • 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 installed or damaged glow plug harness
  • Fuel system issues
  • Injector problems
  • Compression issues in the cylinder

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 glow plug should have a resistance value within the manufacturer's specifications. If it reads open or significantly out of range, replace the glow plug

  4. 4. Check the Glow Plug Control Module

    Inspect the glow plug control module for any signs of damage or corrosion. Ensure that all connections are secure and free of dirt or moisture

  5. 5. Test the control module according to the manufacturer's specifications. If it is malfunctioning, it may need to be replaced

  6. 6. Inspect Wiring and Connectors

    Check the wiring and connectors leading to the glow plug and the control module. Look for frayed wires, loose connections, or any signs of short circuits

  7. 7. Repair or replace any damaged wiring or connectors

  8. 8. Test the Power Supply

    Verify that the glow plug is receiving the correct voltage. Use a multimeter to check the voltage at the glow plug connector while the ignition is in the "on" position (but the engine is not running). It should typically read around 12 volts

  9. 9. If the voltage is low, trace the circuit back to the power source and check for any issues

  10. 10. Check 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

  11. 11. Reprogram or replace the ECM if necessary, but this should be a last resort after all other components have been ruled out

  12. 12. Clear Codes and Test Drive

    After performing repairs, 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 a Professional

    If you are unable to diagnose or fix the issue, it may be best to consult a professional mechanic or technician who has experience with diesel engines and glow plug systems.Conclusion By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P068E code. Always refer to the vehicle's service manual for specific procedures and specifications related to your particular make and model