P1691 — Metering Oil Pump Stepping Motor Circuit Malfunction

What are the symptoms of P1691?

Drivers most often notice: increased fuel consumption in some cases, possible limp mode depending on the affected component, the affected system operates intermittently or not at all, Check Engine Light on.

What does OBD2 code P1691 mean?

P1691 — Metering Oil Pump Stepping Motor Circuit Malfunction. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: corroded, loose or damaged connector, open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit.

Will P1691 clear itself?

Sometimes P1691 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What is the most common cause of P1691?

The most common causes are: corroded, loose or damaged connector, open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit.

How much does it cost to fix P1691?

Repair wiring or connectors — $80–$250; Control module repair — $300–$1,000; Replace the faulty sensor or actuator — $150–$500. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

When your vehicle's engine computer detects a problem with the oil metering pump's stepping motor control, it logs trouble code P1691. This specific fault belongs to the powertrain category, indicating the onboard diagnostics system has observed unexpected behavior from the component or its associated circuitry. The official description—"Metering Oil Pump Stepping Motor Circuit Malfunction"—points toward either an electrical issue in the wiring or a failure within the motor assembly itself.

Unlike simple circuit shorts or opens, P1691 covers a broader range of potential problems. The engine control module runs self-diagnostics on this system constantly while the engine runs. When sensor readings or actuator responses fall outside acceptable parameters for several consecutive drive cycles, the module stores P1691 in memory and illuminates the Check Engine light. The freeze frame data accompanying this code is invaluable—it captures the exact engine speed, load, temperature, and vehicle speed at the moment the fault triggered, giving you precise conditions to replicate during troubleshooting.

The vehicle can typically continue operating after P1691 sets, though you may notice reduced fuel efficiency, intermittent operation of the affected system, or activation of a reduced-power limp mode depending on your specific make and model. Addressing this code promptly prevents secondary damage and restores normal operation.

Common Symptoms

• The Check Engine light remains illuminated after P1691 sets
• Fuel consumption increases noticeably compared to normal driving patterns
• The metering oil pump stepping motor operates erratically or stops responding entirely
• Reduced engine performance or limp-home mode activation in some vehicles
• System-related auxiliary functions become unavailable or behave unpredictably

What Causes P1691

• Internal failure of the metering oil pump stepping motor itself
• Damaged, corroded, loose, or poorly seated electrical connectors in the circuit
• Open or shorted wiring within the harness affecting the motor control circuit
• Faulty driver circuitry or software glitch within the engine control module
• Inadequate ground connection at the component or module level
• Defective sensor or actuator sharing the affected circuit
• Wiring insulation damage from heat, chafing, or environmental contamination

How to Diagnose P1691

1. Connect a quality OBD2 scanner, retrieve code P1691, and record all freeze frame data—this snapshot reveals exactly what conditions triggered the fault and guides your testing strategy.

2. Check for additional diagnostic trouble codes stored alongside P1691. Related codes often expose the true underlying cause rather than the symptom. Simultaneously research manufacturer technical service bulletins for your specific model—many powertrain codes have documented factory remedies or software updates available through dealerships.

3. Perform a thorough visual inspection of the wiring harness and connectors associated with the metering oil pump stepping motor. Look for damaged insulation, corrosion buildup, bent pins, loose retention clips, or any signs of previous repair work that may have degraded over time.

4. If your diagnostic scanner supports bidirectional controls, run the actuator test command for the metering oil pump stepping motor. A component that fails to respond to a direct test command is confirmed defective and warrants replacement.

5. Use a multimeter to verify proper reference voltage, ground integrity, and signal continuity at the motor connector. Compare your readings against manufacturer specifications from a service manual.

6. Conduct a wiggle test on the harness while monitoring live data parameters. Any signal dropout or intermittent reading during physical manipulation points toward a broken wire or loose connection requiring repair.

7. Clear the code, drive the vehicle through a complete drive cycle that recreates the freeze frame conditions, then rescan to confirm P1691 does not reappear—persistent codes indicate an undiscovered fault.

Repair Options

Repair costs for P1691 vary significantly depending on which component actually failed. Independent shop labor rates typically range from $75–$125 per hour depending on region.

• Wiring harness repair or connector replacement: $80–$250. Most failures involve damaged insulation or corroded terminals that can be spliced or cleaned rather than replacing entire assemblies.

• Engine control module diagnosis and repair: $300–$1,000. Module replacement or reprogramming represents a significant expense and should only be considered after all other electrical possibilities are exhausted.

• Metering oil pump stepping motor or related sensor/actuator replacement: $150–$500. Parts pricing varies considerably between original equipment and aftermarket suppliers.

Total Cost Summary

P1691 repair expenses span a wide range because the fault can originate from multiple sources. Wiring fixes sit at the lower end of the spectrum, while control module issues command premium prices. Most independent shops will diagnose the specific cause before recommending repairs—expect a diagnostic fee of $75–$150 that often applies toward subsequent repair work. Addressing the least expensive possibilities first makes financial sense, as the priciest scenario is rarely the actual culprit.

Can You Drive with P1691?

In most driving situations, the vehicle remains operational after P1691 sets, though you may experience diminished performance or notice certain auxiliary systems becoming unavailable. Continue driving only if symptoms remain mild. However, if the malfunction causes stalling, prevents the engine from starting, or triggers warnings affecting brakes or steering, treat this as a priority concern requiring immediate professional diagnosis.