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P0373 Timing Over-Retarded or System Performance Problem

The OBD2 code P0373 indicates that the engine's timing is over-retarded, which means the ignition timing is delayed beyond the acceptable range, potentially leading to performance issues or engine misfires

Definition

The OBD2 code P0373 indicates that the engine's timing is over-retarded, which means the ignition timing is delayed beyond the acceptable range, potentially leading to performance issues or engine misfires

Common causes

  • Faulty crankshaft position sensor
  • Faulty camshaft position sensor
  • Timing chain or belt issues
  • Incorrect ignition timing
  • Faulty engine control module (ECM)
  • Oil flow issues to the timing components
  • Worn timing chain or belt
  • Faulty variable valve timing (VVT) system
  • Vacuum leaks
  • Fuel delivery problems

Common misdiagnoses

  • Faulty crankshaft position sensor
  • Faulty camshaft position sensor
  • Timing chain/belt issues
  • Ignition system problems
  • Fuel delivery issues
  • Vacuum leaks
  • Engine control module (ECM) malfunctions
  • Incorrectly set ignition timing
  • Faulty spark plugs or wires
  • Exhaust system restrictions

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 Timing Components

    Timing Belt/Chain: Check for wear, damage, or misalignment. If the timing belt or chain is stretched or has skipped a tooth, it can cause timing issues

  3. 3. Timing Marks

    Ensure that the timing marks on the crankshaft and camshaft align correctly according to the manufacturer’s specifications

  4. 4. Examine the Crankshaft and Camshaft Position Sensors

    Sensor Condition: Inspect the CKP and CMP sensors for damage, corrosion, or loose connections

  5. 5. Sensor Operation

    Test the sensors with a multimeter to ensure they are functioning correctly. Check the resistance and voltage output as per the manufacturer’s specifications

  6. 6. Check Wiring and Connectors

    Inspect the wiring and connectors related to the CKP and CMP sensors for any signs of damage, fraying, or corrosion. Repair or replace as necessary

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

    Ensure that the ECM is functioning properly. Sometimes, a faulty ECM can lead to incorrect timing adjustments

  8. 8. Check for Vacuum Leaks

    Inspect the intake system for any vacuum leaks that could affect engine performance and timing

  9. 9. Examine Fuel and Ignition Systems

    Ensure that the fuel system is delivering the correct amount of fuel and that the ignition system is functioning properly. Issues in these systems can affect engine timing and performance

  10. 10. Perform a Compression Test

    Conduct a compression test to check for any internal engine issues, such as worn piston rings or valves that may affect timing

  11. 11. Check for Engine Mechanical Issues

    Inspect for any mechanical issues that could affect timing, such as a worn or damaged timing chain/belt tensioner

  12. 12. Clear Codes and Test Drive

    After performing repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns.1

  13. 13. Consult Repair Manual

    Refer to the vehicle’s service manual for specific diagnostic procedures and specifications related to the P0373 code.1

  14. 14. Seek Professional Help

    If the issue persists after performing the above steps, consider seeking assistance from a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you can systematically identify and resolve the underlying issue causing the P0373 code