P0687 2018 GMC Sierra Code - Engine Control Module Power Relay Control Circuit High
Quick Answer
The P0687 diagnostic trouble code (DTC) is indicative of an issue with the Engine Control Module (ECM) power relay control circuit, specifically signaling that the circuit is reading a high voltage condition. Common causes include Faulty Power Relay: The power relay that supplies voltage to the ECM may be malfunctioning or failing, Wiring Issues: Damaged or corroded wiring or connectors in the power relay circuit can lead to high voltage readings, ECM Failure: A defective ECM may incorrectly interpret the voltage levels, triggering the P0687 code. 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
- P0687 2018 GMC Sierra indicates Engine Control Module Power Relay Control Circuit High.
- Common causes
- Common causes include Faulty Power Relay: The power relay that supplies voltage to the ECM may be malfunctioning or failing, Wiring Issues: Damaged or corroded wiring or connectors in the power relay circuit can lead to high voltage readings, ECM Failure: A defective ECM may incorrectly interpret the voltage levels, triggering the P0687 code.
- 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 P0687 2018 GMC Sierra Description
The P0687 diagnostic trouble code (DTC) is indicative of an issue with the Engine Control Module (ECM) power relay control circuit, specifically signaling that the circuit is reading a high voltage condition. The ECM is a critical component in modern vehicles, responsible for managing engine performance, fuel efficiency, emissions, and overall vehicle operation. When the P0687 code is triggered, it suggests that the ECM is not receiving the appropriate voltage from the power relay, which can lead to various performance issues.
Common Causes of P0687 2018 GMC Sierra
- Faulty Power Relay: The power relay that supplies voltage to the ECM may be malfunctioning or failing.
- Wiring Issues: Damaged or corroded wiring or connectors in the power relay circuit can lead to high voltage readings.
- ECM Failure: A defective ECM may incorrectly interpret the voltage levels, triggering the P0687 code.
- Short Circuits: A short circuit in the electrical system could cause excessive voltage to be sent to the ECM.
- Poor Ground Connection: An inadequate ground connection can lead to erratic voltage readings and affect the ECM's operation.
Symptoms of P0687 2018 GMC Sierra
- Engine Stalling: The vehicle may unexpectedly stall while driving due to the ECM losing power.
- Difficulty Starting: The engine may crank but fail to start, or it may take multiple attempts to start.
- Poor Engine Performance: Drivers may notice a decrease in power, acceleration, or overall engine responsiveness.
- Check Engine Light: The check engine light will illuminate on the dashboard, indicating a fault in the engine management system.
- Increased Emissions: The vehicle may fail emissions tests due to improper fuel mixture or combustion issues.
How to Fix P0687 2018 GMC Sierra
- Visual Inspection: Begin with a thorough visual inspection of the power relay, wiring, and connectors for any signs of damage, corrosion, or loose connections.
- Test the Power Relay: Use a multimeter to check the functionality of the power relay. Replace it if it is found to be faulty.
- Inspect Wiring and Connectors: Check the integrity of the wiring and connectors in the power relay circuit. Repair or replace any damaged components.
- ECM Testing: If the power relay and wiring are in good condition, test the ECM for proper operation. Reprogramming or replacing the ECM may be necessary if it is found to be defective.
- Clear Codes and Test Drive: After repairs are made, clear the DTCs using a scan tool and take the vehicle for a test drive to ensure the issue has been resolved.
Cost to Fix P0687 2018 GMC Sierra
The cost to repair the P0687 code can vary significantly based on the specific issue identified during diagnosis. On average, repairs may range from $100 to $600, depending on whether the problem lies with the power relay, wiring, or ECM. Labor costs typically range from $80 to $150 per hour, with the total repair time varying based on the complexity of the issue. In metropolitan areas or at dealerships, rates may be higher, while independent shops often offer more competitive pricing. It's advisable to consult local repair shops for precise estimates tailored to your vehicle's needs and regional labor rates.
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Frequently Asked Questions about P0687 2018 GMC Sierra Code
1. What are the common symptoms of OBDII code P0687 in a 2018 GMC Sierra?
The common symptoms of OBDII code P0687 in a 2018 GMC Sierra include engine stalling, rough idling, loss of power, and in some cases, the vehicle may not start at all.
2. What does the OBDII code P0687 for a 2018 GMC Sierra indicate?
OBDII code P0687 in a 2018 GMC Sierra indicates a problem with the Engine Control Module Power Relay Control Circuit being too high.
3. What are the possible causes of OBDII code P0687 in a 2018 GMC Sierra?
Possible causes of OBDII code P0687 in a 2018 GMC Sierra include a faulty power relay, damaged wiring or connectors in the ECM circuit, or a malfunctioning Engine Control Module itself.
4. How can I diagnose the OBDII code P0687 in my 2018 GMC Sierra?
To diagnose OBDII code P0687 in a 2018 GMC Sierra, you can use an OBDII scanner to read the code, inspect the power relay and related wiring for any damage, and perform continuity tests on the circuit to pinpoint the issue.
5. Can I drive my 2018 GMC Sierra with OBDII code P0687?
It is not recommended to drive your 2018 GMC Sierra with OBDII code P0687, as it can lead to further engine damage or complete failure. It is advisable to address the issue promptly.
6. How can I repair OBDII code P0687 in my 2018 GMC Sierra?
To repair OBDII code P0687 in a 2018 GMC Sierra, you may need to replace the faulty power relay, repair any damaged wiring or connectors, or in some cases, replace the Engine Control Module.
7. Is it necessary to reset the OBDII code P0687 after repairing my 2018 GMC Sierra?
Yes, it is important to clear the OBDII code P0687 after repairing your 2018 GMC Sierra to reset the Check Engine Light and ensure that the issue has been successfully resolved.
8. Can a DIY enthusiast fix OBDII code P0687 in a 2018 GMC Sierra?
Depending on your skill level and access to tools, a DIY enthusiast may be able to fix OBDII code P0687 in a 2018 GMC Sierra by following repair guides and using caution when working with electrical components.
9. What are the long-term effects of ignoring OBDII code P0687 in a 2018 GMC Sierra?
Ignoring OBDII code P0687 in a 2018 GMC Sierra can lead to more severe engine problems, reduced fuel efficiency, and potential safety hazards due to unexpected stalling or loss of power.
10. How can I prevent OBDII code P0687 from occurring in my 2018 GMC Sierra in the future?
To prevent OBDII code P0687 from occurring in your 2018 GMC Sierra in the future, regularly inspect and maintain the power relay and ECM components, address any wiring issues promptly, and avoid overloading electrical circuits in the vehicle.
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