P0685 2017 GMC Sierra Code - Engine Control Module Power Relay Control Circuit Open
Quick Answer
The P0685 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates that there is an issue with the Engine Control Module (ECM) Power Relay Control Circuit being open. Common causes include Faulty ECM power relay, Wiring harness issues or loose connections, Blown fuse related to the ECM power relay. 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 2017 GMC Sierra indicates Engine Control Module Power Relay Control Circuit Open.
- Common causes
- Common causes include Faulty ECM power relay, Wiring harness issues or loose connections, Blown fuse related to the ECM power relay.
- 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 2017 GMC Sierra Description
The P0685 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates that there is an issue with the Engine Control Module (ECM) Power Relay Control Circuit being open. The ECM power relay is responsible for providing power to the ECM, which is the brain of the vehicle's engine management system. When the power relay control circuit is open, it means that there is a break or interruption in the electrical connection between the power relay and the ECM. This can lead to a variety of performance issues and potentially cause the vehicle to stall or not start at all.
Common Causes of P0685 2017 GMC Sierra
- Faulty ECM power relay
- Wiring harness issues or loose connections
- Blown fuse related to the ECM power relay
- Malfunctioning ECM
- Corrosion or damage to electrical components
Symptoms of P0685 2017 GMC Sierra
- Engine stalling or difficulty starting
- Reduced engine performance and power
- Check Engine Light illuminated on the dashboard
- Poor fuel efficiency
- Rough idling or misfiring
How to Fix P0685 2017 GMC Sierra
- Begin by conducting a thorough visual inspection of the wiring harness and connections related to the ECM power relay.
- Test the power relay using a multimeter to determine if it is functioning properly. Replace the relay if necessary.
- Check and replace any blown fuses related to the ECM power relay.
- If the issue persists, perform a diagnostic scan to check for any ECM malfunctions. Replace the ECM if needed.
- Clear the DTC and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P0685 2017 GMC Sierra
The typical repair costs for addressing a P0685 code on a 2017 GMC Sierra can range from $100 to $300, depending on the specific cause of the issue and the cost of parts. This estimate includes the cost of a new power relay, potential wiring repairs, and labor charges. It's important to note that diagnostic time and labor rates can vary, so it's advisable to check with local auto repair shops for a more accurate estimate based on your location and vehicle specifics.
Tech Notes for P0685 2017 GMC Sierra
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Frequently Asked Questions about P0685 2017 GMC Sierra Code
1. What does the OBDII code P0685 mean on a 2017 GMC Sierra?
P0685 indicates that the Engine Control Module (ECM) Power Relay Control Circuit is open, meaning the ECM is not receiving the proper power supply due to an electrical issue.
2. What are the common symptoms of code P0685 on a 2017 GMC Sierra?
Symptoms include the engine not starting, stalling while driving, a check engine light, or intermittent loss of power.
3. What causes the P0685 code to appear on a 2017 GMC Sierra?
Common causes include a faulty ECM power relay, damaged wiring or connectors in the ECM power circuit, a blown fuse, or a malfunctioning ECM.
4. Can I drive my 2017 GMC Sierra with a P0685 code?
Driving with this code is not recommended, as it can lead to engine stalling or prevent the vehicle from starting, potentially leaving you stranded.
5. How do I diagnose the P0685 code on a 2017 GMC Sierra?
Start by checking the ECM power relay, inspecting the wiring and connectors for damage, and testing the fuse associated with the ECM circuit.
6. How do I fix the P0685 code on a 2017 GMC Sierra?
Repairs typically involve replacing a faulty ECM power relay, repairing or replacing damaged wiring, replacing a blown fuse, or, in rare cases, replacing the ECM.
7. How much does it cost to repair the P0685 code on a 2017 GMC Sierra?
Repair costs can vary, but replacing an ECM power relay typically costs $50–$100, while wiring repairs may cost $100–$300 depending on the extent of the damage.
8. Can a dead battery cause a P0685 code on a 2017 GMC Sierra?
A weak or dead battery can indirectly cause issues with the ECM power circuit, but the code is more likely related to a specific relay or wiring fault.
9. How can I prevent a P0685 code from occurring on my 2017 GMC Sierra?
Regularly inspect the electrical components, fuses, and relays in the ECM circuit for signs of wear or damage, and address any issues promptly.
10. Do I need special tools to fix the P0685 code on a 2017 GMC Sierra?
Basic tools like a multimeter and a relay tester can help diagnose the issue, but more advanced repairs may require specialized diagnostic equipment.
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