WOMS
P code powertrain Medium severity

P1685 Metering Oil Pump Stepping Motor Circuit Malfunction

The OBD2 code P1685 indicates a malfunction in the metering oil pump stepping motor circuit, which affects the operation of the oil pump in the engine's fuel system

Definition

The OBD2 code P1685 indicates a malfunction in the metering oil pump stepping motor circuit, which affects the operation of the oil pump in the engine's fuel system

Common causes

  • Faulty metering oil pump stepping motor
  • Wiring issues (shorts, opens, or corrosion)
  • Poor electrical connections
  • Failed engine control module (ECM)
  • Faulty sensors related to the oil pump
  • Software issues in the ECM
  • Low oil pressure or oil level
  • Mechanical failure in the oil pump system

Common misdiagnoses

  • Faulty Engine Control Module (ECM)
  • Wiring issues or shorts in the circuit
  • Defective oil pump
  • Malfunctioning oil pressure sensor
  • Issues with the vehicle's battery or charging system
  • Problems with the ignition system
  • Faulty connectors or terminals in the circuit

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. Ensure that the motor is receiving the correct voltage as specified in the vehicle’s 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. Examine the Engine Control Module (ECM)

    If all other components check out, the issue may lie within the ECM. Check for any software updates or reprogramming that may be necessary

  11. 11. Inspect the ECM for any signs of damage or corrosion

  12. 12. Clear Codes and Test Drive

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

  13. 13. Take the vehicle for a test drive to see if the code returns. Monitor the vehicle’s performance and any related symptoms

  14. 14. 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 P1685 code