The Engine Fault Code P0686 refers to an issue with the power relay control circuit for the Engine Control Module (ECM) or Powertrain Control Module (PCM). This code indicates that the control circuit is experiencing a low voltage condition, which can affect the operation of the engine.
Possible Causes:
1. Faulty ECM/PCM: The control module itself may be malfunctioning.
2. Wiring Issues: Damaged or corroded wiring can cause low voltage.
3. Bad Relay: The power relay for the ECM/PCM might be faulty.
4. Blown Fuse: A blown fuse in the circuit can lead to low voltage.
5. Ground Issues: Poor grounding can also cause voltage drops.
Alternative Meanings by Manufacturer:
While P0686 typically has the same general meaning across various manufacturers, there can be slight differences in the specifics. Here are some potential variations:
– P0686 in Porsche: May indicate a specific issue with the DME (Digital Motor Electronics) control unit.
– P0686 in Mercedes: Could be linked to issues with the power distribution module or specific wiring harnesses.
– P0686 in Audi: Might involve the engine control unit and associated power relay, similar to Porsche.
– P0686 in Mini: Could relate to the engine management system and its power supply.
– P0686 in Jaguar: May indicate problems with the power distribution system affecting the engine control.
– P0686 in Land Rover: Could be tied to the engine management system and its power relay.
What to Do:
1. Scan the Code: Use an OBD-II scanner to confirm the code and check for additional codes.
2. Inspect Wiring: Look for damaged wires or loose connections in the relay circuit.
3. Check the Relay: Test or replace the power relay for the ECM/PCM.
4. Test Voltage: Measure the voltage at the relay and the ECM/PCM to ensure it`s within specifications.
5. Consult a Professional: If you`re unsure, its best to take your vehicle to a qualified mechanic for further diagnosis.
By addressing this code promptly, you can help ensure your vehicle runs smoothly and avoid more serious issues down the line.
The Engine Fault Code P0686 typically indicates a problem with the Power Relay Control Circuit for the Engine Control Module (ECM) or Powertrain Control Module (PCM). This code can be triggered by several issues, and while the general cause is similar across different manufacturers, there can be some variations. Heres a breakdown of possible causes:
Common Causes of P0686:
1. Faulty Power Relay: The relay that controls power to the ECM/PCM might be malfunctioning or damaged.
2. Wiring Issues: Damaged, corroded, or loose wiring in the control circuit can cause low voltage or poor connection.
3. ECM/PCM Failure: The control module itself may be faulty, leading to incorrect signals and triggering the code.
4. Ground Issues: Poor grounding for the ECM/PCM can lead to low voltage readings.
5. Fuses: A blown fuse related to the power supply for the ECM/PCM can also cause this code.
Manufacturer-Specific Considerations:
– Porsche: In some models, the issue could be linked to the ignition switch or the battery voltage being low.
– Mini: Mini vehicles may have additional complexities with their wiring harnesses, especially if there has been previous work on the electrical system.
– Mercedes: Mercedes vehicles may have software-related issues in the ECM/PCM that require a software update to resolve the code.
– Audi: Audi models might show this code if there are issues with the CAN bus communication, which affects the ECM/PCM.
– Jaguar: On some Jaguar models, the key fob or immobilizer system could interfere with the power relay, leading to this code.
– Land Rover: For Land Rover, intermittent electrical issues can cause this code, especially if there are multiple fault codes present.
Steps to Diagnose:
1. Check the Relay: Inspect and test the power relay for proper operation.
2. Inspect Wiring: Look for any damaged or corroded wires in the circuit.
3. Check Fuses: Ensure all relevant fuses are intact.
4. Test the ECM/PCM: If all else checks out, consider testing or replacing the ECM/PCM.
5. Scan for Additional Codes: Look for any other diagnostic trouble codes that may provide more context.
By following these steps, you can narrow down the cause of the P0686 code and take appropriate action to resolve the issue.
The Engine Fault Code P0686 indicates a problem with the ECM/PCM (Engine Control Module/Powertrain Control Module) power relay control circuit. This code can appear in various European cars, including Porsche, Mini, Mercedes, Audi, Jaguar, and Land Rover. Heres how to troubleshoot and fix this issue:
General Steps to Fix P0686:
1. Check the Battery:
– Ensure the battery is fully charged and in good condition. A weak battery can cause power issues.
2. Inspect Fuses:
– Check the fuses related to the ECM/PCM power relay. A blown fuse can disrupt power to the module.
3. Examine the Relay:
– Locate the ECM/PCM power relay. This is often found in the fuse box. Test the relay by swapping it with another similar relay (if available) to see if the issue resolves.
4. Inspect Wiring and Connectors:
– Look for damaged or corroded wiring and connectors leading to the ECM/PCM. Repair or replace any damaged components.
5. Scan for Additional Codes:
– Use an OBD-II scanner to check for other fault codes that might give more context to the issue.
6. Test the ECM/PCM:
– If all else seems fine, the ECM/PCM itself might be faulty. Testing or replacing it should be done by a professional, as it requires specific tools and knowledge.
Manufacturer-Specific Considerations:
– Porsche:
– Check for software updates for the ECM. Sometimes, a simple reflash can resolve power issues.
– Mini:
– Mini vehicles often have specific wiring harness issues. Inspect the harness for wear, especially near the engine bay.
– Mercedes:
– Mercedes models may have a secondary relay for the ECM. Ensure both relays are functioning properly.
– Audi:
– Audi vehicles might have a more complex electrical system. Use a wiring diagram for your specific model to trace the circuit.
– Jaguar:
– Jaguars can have issues with the battery management system. Ensure that the battery management system is functioning correctly.
– Land Rover:
– Check for any software updates or recalls related to the ECM. Land Rover models sometimes require dealer intervention for software-related issues.
Final Notes:
Always disconnect the battery before working on electrical components to avoid shorts or further damage. If you`re not comfortable with these steps, its best to consult a professional mechanic who specializes in European cars.
Driving with a P0686 code, which indicates a problem with the ECM/PCM power relay control circuit, is not recommended. This code typically means theres an issue with the power supply to the engine control module (ECM) or powertrain control module (PCM). Heres a breakdown of the potential risks and manufacturer specifics:
General Risks:
1. Engine Performance Issues: The vehicle may experience poor performance, stalling, or difficulty starting.
2. Electrical Problems: Other electrical components may also malfunction since the ECM controls various systems.
3. Safety Concerns: If the engine stalls while driving, it could lead to a loss of power steering and brakes, increasing the risk of an accident.
Manufacturer-Specific Considerations:
1. Porsche:
– Generally, it`s best to avoid driving until the issue is resolved. Porsche vehicles are sensitive to electrical issues, and continued driving could lead to more significant problems.
2. Mini:
– Similar to Porsche, Mini vehicles can experience erratic behavior due to electrical issues. Its advisable to have it checked out before driving.
3. Mercedes:
– Mercedes vehicles often have complex electrical systems. Driving with this code may lead to further complications, so its best to get it diagnosed.
4. Audi:
– Audi vehicles can also face performance issues with this code. Its safer to address it before driving long distances.
5. Jaguar:
– Jaguars are prone to electrical issues. It`s advisable to resolve the P0686 code before driving to avoid potential breakdowns.
6. Land Rover:
– Land Rover vehicles may suffer from similar electrical problems. Avoid driving until the issue is fixed to prevent stalling or other failures.
Our take, its not safe to drive with a P0686 code across all these manufacturers. It`s best to get the vehicle diagnosed and repaired to ensure safe driving.
