P0685 Code - Engine Control Module Power Relay Control Circuit Open
Quick Answer
The diagnostic trouble code P0685 indicates that there is an issue with the engine control module power relay control circuit being open. Common causes include Faulty engine control module power relay, Wiring or connection issues in the power relay circuit, Corrosion or damage to the power relay control circuit. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0685 indicates Engine Control Module Power Relay Control Circuit Open.
- Common causes
- Common causes include Faulty engine control module power relay, Wiring or connection issues in the power relay circuit, Corrosion or damage to the power relay control circuit.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0685 Description
The diagnostic trouble code P0685 indicates that there is an issue with the engine control module power relay control circuit being open. This means that there is a malfunction in the circuit that controls the power relay for the engine control module, which can lead to a variety of performance issues in the vehicle. The engine control module (ECM) is a crucial component of the vehicle's electronic control system, responsible for managing various engine functions such as fuel injection, ignition timing, and emissions control. When the power relay control circuit is open, the ECM may not receive the necessary power supply, leading to malfunctions and potential engine performance issues.
Common Causes of P0685
- Faulty engine control module power relay
- Wiring or connection issues in the power relay circuit
- Corrosion or damage to the power relay control circuit
- ECM software or hardware issues
- Electrical system problems
Symptoms of P0685
- Engine stalling or rough idling
- Difficulty starting the engine
- Decreased fuel efficiency
- Illumination of the Check Engine Light
- Loss of engine power
How to Fix P0685
- Diagnose the issue using a scan tool to confirm the P0685 code and pinpoint the exact cause.
- Inspect the engine control module power relay and related wiring for any visible damage or corrosion.
- Test the power relay control circuit for continuity and proper voltage supply.
- Replace the faulty power relay, repair any damaged wiring or connections, and reset the ECM codes.
- Clear the diagnostic trouble codes, test drive the vehicle to ensure the issue is resolved, and recheck for any recurring codes.
Cost to Fix P0685
The cost of repairing a P0685 code can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. On average, the repair cost for this type of issue could range from $100 to $300, including parts and labor. However, it's important to note that the final cost may be higher if additional components need to be replaced or if the diagnostic process is more time-consuming. It's recommended to consult with a professional mechanic for an accurate cost estimate tailored to your vehicle's make and model.
Tech Notes for P0685
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Code P0685 Information for Specific Makes
- P0685 Acura — Engine Control Module Power Relay Control Circuit Open
- P0685 Audi — Engine Control Module Power Relay Control Circuit Open
- P0685 Buick — Engine Control Module Power Relay Control Circuit Open
- P0685 Cadillac — Engine Control Module Power Relay Control Circuit Open
- P0685 Chevrolet — Engine Control Module Power Relay Control Circuit Open
- P0685 Chrysler — Auto Shutdown Relay Control Circuit Failure
- P0685 Dodge — Auto Shutdown Relay Control Circuit Failure
- P0685 Ford — Powertrain Control Module Power Relay Control Circuit Open
- P0685 GMC — Engine Control Module Power Relay Control Circuit Open
- P0685 Honda — Engine Control Module Power Relay Control Circuit Open
- P0685 Hyundai — Engine Control Module Power Relay Control Circuit Open
- P0685 Isuzu — Engine Control Module Power Relay Control Circuit Open
- P0685 Jeep — Auto Shutdown Relay Control Circuit Failure
- P0685 KIA — Engine Control Module Power Relay Control Circuit Open
- P0685 Lincoln — Powertrain Control Module Power Relay Control Circuit Open
- P0685 Mazda — Engine Control Module Power Relay Control Circuit Open
- P0685 Mercury — Powertrain Control Module Power Relay Control Circuit Open
- P0685 Mitsubishi — Engine Control Module Power Relay Control Circuit Open
- P0685 Pontiac — Engine Control Module Power Relay Control Circuit Open
- P0685 Saturn — Engine Control Module Power Relay Control Circuit Open
- P0685 Suzuki — Engine Control Module Power Relay Control Circuit Open
- P0685 Volkswagen — Engine Control Module Power Relay Control Circuit Open
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