P1685 — Metering Oil Pump Malfunction

P1685 — Metering Oil Pump Malfunction. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: faulty sensor or actuator of the affected circuit, poor ground connection, open or shorted wiring in the circuit.

For Ford vehicles

metering oil pump stepping motor cont. circuit Mazda

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P1685 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the metering oil pump for damage, corrosion, chafing or poor contact.
Subsystem check Run the module's actuator test for the metering oil pump if your scanner supports it — a component that does not respond to a direct command is confirmed faulty.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P1685 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P1685 (parts and labor, USD, independent shop rates): Repair wiring or connectors: $80–$250; Replace the faulty sensor or actuator: $150–$500; Control module repair: $300–$1,000. Overall, fixing P1685 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

Will P1685 clear itself?

Sometimes P1685 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.

Is it safe to drive with P1685?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How do I diagnose P1685 myself?

Start with a scan: confirm P1685, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the metering oil pump, and verify the suspect component against live data before buying parts.

How much does it cost to fix P1685?

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

What does OBD2 code P1685 mean?

When your check engine light comes on and a scan tool reveals code P1685, you're dealing with a fault in the metering oil pump system. This code belongs to the powertrain group and signals that the engine control module has detected a malfunction during its self-diagnostic checks of the oil metering circuit or its associated control logic. P1685 is not triggered by a single anomalous reading; instead, the module must observe the fault condition occur repeatedly under specific operating parameters before it will store the code and illuminate the warning lamp.

The metering oil pump plays a critical role in maintaining proper engine lubrication under varying conditions. Unlike a simple pressure relief valve, a metering design precisely controls oil flow to different engine passages based on load, temperature, and RPM demands. When the control module runs its internal self-test on this circuit, it expects specific voltage patterns, ground integrity, and signal responses. If any of these fall outside acceptable ranges across multiple test cycles, P1685 gets set. The freeze frame data stored alongside P1685 captures the exact engine conditions — load percentage, RPM, coolant temperature, vehicle speed — present when the fault first occurred, giving you a target to aim for when recreating the problem.

Understanding why this code requires multiple failed checks helps explain the diagnostic approach. Because P1685 can originate from the pump itself, its wiring, connectors, fuses, ground paths, or even the control module's driver circuitry, a methodical process beats guesswork. The module essentially says, "I've tested this circuit several times and consistently received a result that doesn't match expectations." Your job is to determine whether the failure lives in the hardware, the wiring, or the module's interpretation of the signal.

Symptoms of P1685

The Check Engine Light will be illuminated on the dashboard. The system affected by this fault may operate inconsistently, cycling between normal function and failure, or it may stop working entirely until the fault clears. Some vehicles experience reduced performance modes, forcing the engine into a limp-home configuration that limits power to protect components. Fuel consumption can increase in certain cases, particularly if the metering function erratically delivers too much or too little oil to critical passages. The severity of symptoms often correlates with how severely the pump or circuit has failed — a marginal wiring issue might cause occasional hiccups, while a failed pump produces consistent problems.

Common Causes of P1685

The internal pump mechanism itself can wear out or suffer physical damage, creating a condition the control module detects during self-testing. Wiring problems rank among the most frequent culprits: broken strands inside insulation, chafing from engine movement, or insulation breakdown from heat and oil exposure can all interrupt the signal. Connectors at the pump or module may corrode, develop loose pins, or suffer broken locking tabs allowing high-resistance or intermittent contact. A blown fuse dedicated to the metering circuit will obviously prevent proper function and trigger the fault. Poor ground connections at the engine or body can corrupt voltage readings the module expects to see as stable references. The control module's own driver circuitry or embedded software can also fail, though this represents a less common scenario than external wiring issues. Finally, short circuits to power or ground anywhere in the wiring harness can create conditions that look like component failure to the testing logic.

Diagnosing P1685

Start by connecting an OBD2 scanner, confirming P1685 is stored in the powertrain control module, and recording all freeze frame data — this snapshot reveals exactly what was happening when the fault triggered. Check for any other stored codes that might point toward a related system failure; secondary codes often expose the root cause. Consult manufacturer technical service bulletins for your specific make and model — factory updates or known fixes may exist for this particular code. Next, perform a thorough visual inspection of the wiring harness routing near the metering oil pump, looking for damaged insulation, melted sections, rubbed-through spots, or evidence of oil contamination. If your scanner supports module-specific actuator tests, command the metering pump to activate and verify it responds with the expected behavior — no response confirms a hardware problem. Use a multimeter to check for proper reference voltage at the pump connector, verify ground resistance is minimal, and confirm signal wire continuity between the pump and control module. During these electrical checks, gently wiggle the harness and connectors while monitoring readings; any fluctuation suggests broken wires or loose terminals. After addressing any found issues, clear the code, perform a complete drive cycle that includes the conditions from your freeze frame data, then rescan to confirm P1685 does not return.

Repair Options and Costs

Wiring repairs or connector replacement typically resolve P1685 when the fault lies in the harness or terminals. Professional labor for harness repair or connector pins runs between eighty and two hundred fifty dollars depending on accessibility. If testing confirms the metering oil pump itself has failed, replacement of the sensor or actuator assembly generally costs one hundred fifty to five hundred dollars for parts and installation. When troubleshooting ultimately points to the engine control module as the source, module repair or replacement can range from three hundred to one thousand dollars depending on whether the solution involves software reprogramming, internal board repair, or full unit replacement.

Total Repair Cost

The wide range reflects how differently this code can resolve depending on what's actually broken. Most situations involving P1685 end up costing between eighty and one thousand dollars total. Independent shop labor rates typically add fifty to one hundred twenty dollars per hour on top of parts costs. An accurate diagnosis before purchasing components always saves money — the most expensive repair scenario is rarely where you should start.

Can You Drive with P1685?

In most cases, the vehicle remains drivable after P1685 sets, though you may notice diminished performance, reduced fuel efficiency, or an auxiliary system that no longer functions properly. The limp mode condition some vehicles enter provides enough operation to reach a repair facility safely. However, if the car exhibits stalling, failure to start, or warnings related to braking or steering assist, treat the situation as urgent and seek immediate service. These additional symptoms suggest the underlying condition may be affecting safety-critical systems beyond the metering oil pump circuit.