WOMS
P code powertrain Medium severity

P1686 Metering Oil Pump Stepping Motor Circuit Malfunction

The OBD2 code P1686 indicates a malfunction in the metering oil pump stepping motor circuit, which affects the operation of the oil pump that regulates fuel delivery in the engine

Definition

The OBD2 code P1686 indicates a malfunction in the metering oil pump stepping motor circuit, which affects the operation of the oil pump that regulates fuel delivery in the engine

Common causes

  • Faulty metering oil pump stepping motor
  • Open or shorted wiring in the circuit
  • Poor electrical connections or corroded terminals
  • Failed engine control module (ECM)
  • Faulty power supply to the motor
  • Malfunctioning sensors related to the oil pump
  • Software issues in the ECM
  • Mechanical blockage in the oil pump system

Common misdiagnoses

  • Faulty engine control module (ECM)
  • Wiring issues or shorts in the circuit
  • Defective oil pump
  • Faulty oil pressure sensor
  • Incorrect oil level or quality
  • Issues with the vehicle's electrical system
  • Problems with the fuel pump or fuel system
  • Malfunctioning throttle position sensor (TPS)

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 Wiring and Connectors

    Visually inspect the wiring and connectors associated with the metering oil pump stepping motor. Look for signs of damage, corrosion, or loose connections

  3. 3. Ensure that all connectors are securely attached and free of dirt or moisture

  4. 4. Test the Stepping Motor

    If accessible, test the metering oil pump stepping motor for proper operation. This may involve applying power directly to the motor to see if it functions correctly

  5. 5. Check the resistance of the motor windings with a multimeter to ensure they are within specifications

  6. 6. Check Power and Ground

    Use a multimeter to check for proper voltage at the stepping motor connector while the ignition is on. Ensure that the motor is receiving the correct voltage as specified in the service manual

  7. 7. Verify that the ground connection is solid and free of corrosion

  8. 8. Inspect the Fuel System

    Check the fuel system for any blockages or issues that could affect the operation of the metering oil pump. This includes inspecting fuel lines, filters, and the fuel tank

  9. 9. Ensure that the fuel is clean and free of contaminants

  10. 10. Scan for PCM Issues

    The Powertrain Control Module (PCM) may be malfunctioning or have a software issue. Check for any available updates or reprogramming that may be needed

  11. 11. If the PCM is suspected to be faulty, further diagnostic testing may be required

  12. 12. Check for Mechanical Issues

    Inspect the metering oil pump itself for any mechanical failures or blockages that could prevent it from operating correctly

  13. 13. Ensure that the pump is not seized or damaged

  14. 14. Clear Codes and Test Drive

    After performing the necessary repairs or adjustments, clear the trouble codes using the OBD-II scanner

  15. 15. Take the vehicle for a test drive to see if the code returns. Monitor the vehicle's performance to ensure that the issue has been resolved

  16. 16. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle make and model. By following these troubleshooting steps, you can systematically identify and resolve the issue associated with the P1686 code