P0685 Mitsubishi Code - Engine Control Module Power Relay Control Circuit Open
Quick Answer
The P0685 code for Mitsubishi vehicles indicates a problem with the Engine Control Module (ECM) power relay control circuit being open. Common causes include Damaged Wiring: Corrosion, fraying, or breakage in the wiring connecting the power relay to the ECM can cause an open circuit, Faulty Power Relay: A malfunctioning power relay can prevent the proper flow of electricity to the ECM, Blown Fuse: A blown fuse in the power relay control circuit can disrupt the power supply to the ECM. 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 Mitsubishi indicates Engine Control Module Power Relay Control Circuit Open.
- Common causes
- Common causes include Damaged Wiring: Corrosion, fraying, or breakage in the wiring connecting the power relay to the ECM can cause an open circuit, Faulty Power Relay: A malfunctioning power relay can prevent the proper flow of electricity to the ECM, Blown Fuse: A blown fuse in the power relay control circuit can disrupt the power supply to the ECM.
- 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 Mitsubishi Description
The P0685 code for Mitsubishi vehicles indicates a problem with the Engine Control Module (ECM) power relay control circuit being open. The ECM is responsible for controlling various engine functions, such as fuel injection, ignition timing, and emissions systems. The power relay control circuit is a crucial component that supplies power to the ECM, allowing it to function properly. When this circuit is open, it means that there is a break or interruption in the electrical connection, preventing the ECM from receiving the necessary power to operate effectively.
Common Causes of P0685 Mitsubishi
- Damaged Wiring: Corrosion, fraying, or breakage in the wiring connecting the power relay to the ECM can cause an open circuit.
- Faulty Power Relay: A malfunctioning power relay can prevent the proper flow of electricity to the ECM.
- Blown Fuse: A blown fuse in the power relay control circuit can disrupt the power supply to the ECM.
- ECM Malfunction: In rare cases, the ECM itself may be faulty and unable to receive power correctly.
Symptoms of P0685 Mitsubishi
- Check Engine Light: The most common symptom associated with this code is the illumination of the Check Engine Light on the dashboard.
- Engine Stalling: The vehicle may experience intermittent stalling or rough idling due to the ECM not receiving proper power.
- Poor Fuel Efficiency: As the ECM may not be able to regulate fuel injection accurately, the vehicle may exhibit decreased fuel efficiency.
- Inability to Start: In severe cases, the vehicle may not start at all due to the ECM not functioning properly.
How to Fix P0685 Mitsubishi
- Diagnose the Issue: Use a diagnostic tool to pinpoint the exact cause of the open circuit in the power relay control circuit.
- Inspect Wiring and Connectors: Check the wiring and connectors for any damage or corrosion, repairing or replacing as necessary.
- Test Power Relay: Test the power relay to ensure it is functioning correctly and replace if faulty.
- Check Fuses: Inspect the fuses related to the power relay control circuit and replace any blown fuses.
- Replace ECM (if necessary): If the ECM is determined to be the cause of the issue, it may need to be replaced to resolve the problem.
Cost to Fix P0685 Mitsubishi
The typical repair costs for addressing the P0685 code in a Mitsubishi vehicle can range from $150 to $500, depending on the specific cause of the issue and the cost of parts and labor in your area. This estimate includes the cost of diagnosing the problem, replacing any damaged wiring or connectors, testing and replacing the power relay if necessary, and potentially replacing the ECM. It is important to note that labor rates at auto repair shops can vary significantly, so it is advisable to check with local shops for a more accurate estimate based on your location and vehicle model.
Tech Notes for P0685 Mitsubishi
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Frequently Asked Questions about P0685 Mitsubishi Code
1. What does the OBDII code P0685 mean for a Mitsubishi vehicle?
The P0685 code indicates an open circuit in the Engine Control Module (ECM) power relay control, meaning the ECM is not receiving the necessary power to function properly.
2. What are common symptoms of the P0685 code in a Mitsubishi?
Symptoms may include difficulty starting the engine, engine stalling, poor performance, or the inability to start the vehicle altogether.
3. What causes the P0685 code in Mitsubishi vehicles?
Common causes include a faulty ECM power relay, damaged wiring or connectors in the relay circuit, or a malfunctioning ECM.
4. How can I diagnose the P0685 code in my Mitsubishi?
Start by inspecting the ECM power relay, wiring, and connectors for damage. Use a multimeter to check continuity in the circuit and test the relay for proper operation.
5. Can a bad battery cause the P0685 code on my Mitsubishi?
A weak or failing battery can contribute to electrical issues, including this code, if it affects the ECM power relay operation or circuit continuity.
6. How do I fix the P0685 code on my Mitsubishi?
Repairs may include replacing the ECM power relay, repairing or replacing damaged wiring or connectors, or, in rare cases, replacing the ECM itself.
7. Is it safe to drive my Mitsubishi with the P0685 code?
Driving with this code is not recommended, as it can lead to stalling or complete engine failure, which may leave you stranded.
8. How much does it cost to repair the P0685 code on a Mitsubishi?
Repair costs can vary, but replacing an ECM power relay typically costs $20-$60, while wiring repairs or ECM replacement can be significantly higher.
9. Can I clear the P0685 code without repairing the issue?
Clearing the code without addressing the underlying problem may result in the code returning and continued performance issues.
10. Does the P0685 code always require ECM replacement?
No, ECM replacement is rarely necessary. Most cases involve fixing wiring issues or replacing the ECM power relay.
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