P1687 Metering Oil Pump Stepping Motor Circuit Malfunction

Definition

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 oil pump assembly
• Software issues in the ECM

Common misdiagnoses

• Faulty engine control module (ECM)
• Wiring issues or shorts in the circuit
• Defective oil pump
• Faulty oil pressure sensor
• Issues with the vehicle's electrical system
• Incorrectly diagnosed fuel system problems
• Misinterpretation of other related codes

Troubleshooting steps

1. 1. Check for Additional Codes

   Use an OBD-II scanner to check for any other trouble codes that may be present. Addressing related codes can help in diagnosing the root cause of the problem

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. Repair or replace any damaged components

3. 3. Test the Stepping Motor

   If accessible, test the metering oil pump stepping motor for proper operation. This may involve checking the resistance of the motor windings and ensuring that it operates when commanded by the engine control module (ECM)

4. 4. Check Power and Ground

   Use a multimeter to check for proper voltage and ground at the stepping motor connector. Ensure that the motor is receiving the correct voltage when the engine is running

5. 5. Inspect the ECM

   If the wiring and motor are functioning correctly, the issue may lie with the engine control module. Check for any software updates or reprogramming that may be necessary

6. 6. Look for Fuel System Issues

   Since the metering oil pump is part of the fuel system, check for any fuel delivery issues, such as clogged filters, low fuel pressure, or problems with the fuel injectors

7. 7. Perform a Visual Inspection

   Check for any signs of leaks or damage in the fuel system that could affect the operation of the metering oil pump

8. 8. 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

9. 9. Consult Technical Service Bulletins (TSBs)

   Check for any manufacturer-specific TSBs related to the P1687 code for your vehicle make and model. There may be known issues or recommended fixes

10. 10. Seek Professional Help

    If the problem persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with your specific vehicle and its systems. By following these troubleshooting steps, you can systematically identify and resolve the issue associated with the P1687 code