01 Inside the Three-Way Catalytic Converter: A Breakdown of It… • 02 This Is Why Your Car’s Headrest Is A Safety Tool • 03 What Is Blow-By & How to Prevent It From Harming Your Engine • 04 Tire Talk: Exploring Tread Patterns, Tire Pressure, and Lon… • 05 Diesel Particulate Filter (DPF) Cleaning: DIY vs. Professio… • 06 When Should the Oxygen Sensor Be Replaced? A Comprehensive • 07 What Are the Symptoms of a Failing Transmission Control Mod… • 08 Oil filter vs. oil: Which is more important to change? • 09 The Sneaky Mechanical Piece That Increases Fuel Consumption… • 10 This One Oil Filter Mistake Could Be Silently Destroying Yo… •

DTC codes / Mazda codes / P1687

P1687 · MazdaMetering Oil Pump Stepping Motor Cont Circuit

P1687 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an open or short circuit in the control circuit for the metering oil pump stepping motor. The PCM monitors the electrical current through the motor's control circuit and sets this code when the expected current is out of range, which prevents the pump from delivering the precise oil quantity required for engine lubrication.

SystemPowertrain
Code typeMazda specific
SeverityHigh
Fix difficultyProfessional
AreaComputer and output circuits

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • Rough idle or engine hesitation due to improper oil metering affecting combustion.
  • Increased oil consumption or blue smoke from the exhaust if the pump fails to deliver oil.
  • Reduced engine performance or power loss under load.
  • In severe cases, engine knocking or seizure from inadequate lubrication.
  • The vehicle may enter limp mode, limiting engine speed to protect the engine.

Common causes, most likely first

  1. Damaged or corroded wiring in the metering oil pump control circuit.
  2. Failed metering oil pump stepping motor.
  3. Poor electrical connection at the pump motor connector.
  4. Faulty powertrain control module (PCM) driver circuit.
  5. Open or shorted control wire between the PCM and the pump motor.
  6. Contamination or debris causing the stepping motor to bind mechanically.

How to diagnose and fix it

  1. Inspect the metering oil pump motor connector and wiring for corrosion, damage, or loose pins; clean or repair as needed.
  2. Measure the resistance of the stepping motor windings and compare to the manufacturer's specification; replace the motor if out of spec.
  3. Check for continuity and short-to-ground or short-to-power on the control circuit between the PCM and the pump motor; repair the harness if faulty.
  4. Test the PCM output signal to the pump motor with an oscilloscope or a bidirectional scan tool; replace the PCM if the driver circuit is defective.
  5. Verify oil supply lines and pump mechanism for blockages or mechanical binding; clean or replace components as required.
  6. Clear the diagnostic trouble codes (DTCs) and perform a road test to confirm the repair; monitor live data for proper pump operation.

Metering Oil Pump Circuit Checks

  • A common oversight is assuming the pump motor itself is at fault when the real issue is a chafed wire in the harness near the engine mount or exhaust manifold.
  • The code can be set intermittently by a poor ground connection at the pump motor mounting bolt, which is often overlooked during diagnosis.
  • On some Mazda models, the metering oil pump is integrated into the oil pump assembly, so a circuit fault may require replacing the entire assembly rather than just the motor.
  • A failing PCM driver can mimic a faulty pump motor; always test the control signal at the PCM before condemning the motor.
  • This code does not always mean the pump has failed completely; it can indicate a marginal circuit resistance that only triggers the code under specific temperature or vibration conditions.

Can I keep driving with P1687?

Driving with P1687 is not recommended because the engine may not receive adequate lubrication, leading to catastrophic damage. If you must drive, keep the engine at low speed and load, and have the vehicle towed to a repair facility as soon as possible.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Mazda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage