P0687 2015 GMC Sierra Code - Engine Control Module Power Relay Control Circuit High
Quick Answer
The P0687 code indicates a problem with the Engine Control Module (ECM) power relay control circuit, specifically that the circuit is registering a high voltage condition. Common causes include Faulty ECM Power Relay: A malfunctioning relay can cause improper voltage levels in the control circuit, Short Circuit in Wiring: Damaged or frayed wiring can lead to a short circuit, causing high voltage readings, Corrosion or Poor Connections: Corroded connectors or poor electrical connections can disrupt the flow of electricity, leading to high voltage conditions. 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 2015 GMC Sierra indicates Engine Control Module Power Relay Control Circuit High.
- Common causes
- Common causes include Faulty ECM Power Relay: A malfunctioning relay can cause improper voltage levels in the control circuit, Short Circuit in Wiring: Damaged or frayed wiring can lead to a short circuit, causing high voltage readings, Corrosion or Poor Connections: Corroded connectors or poor electrical connections can disrupt the flow of electricity, leading to high voltage conditions.
- 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 2015 GMC Sierra Description
The P0687 code indicates a problem with the Engine Control Module (ECM) power relay control circuit, specifically that the circuit is registering a high voltage condition. This code is typically triggered when the ECM detects a voltage level that exceeds its normal operating range on the power relay control circuit. The ECM relies on this relay to manage power distribution to various engine components, including fuel injectors, ignition coils, and other critical systems.
Common Causes of P0687 2015 GMC Sierra
- Faulty ECM Power Relay: A malfunctioning relay can cause improper voltage levels in the control circuit.
- Short Circuit in Wiring: Damaged or frayed wiring can lead to a short circuit, causing high voltage readings.
- Corrosion or Poor Connections: Corroded connectors or poor electrical connections can disrupt the flow of electricity, leading to high voltage conditions.
- Defective ECM: In rare cases, the ECM itself may be faulty, causing it to misinterpret voltage levels.
- Battery Voltage Issues: An overcharging battery or faulty alternator can lead to excessive voltage being supplied to the ECM.
Symptoms of P0687 2015 GMC Sierra
- Difficulty Starting: The vehicle may struggle to start or may not start at all due to insufficient power reaching the ECM.
- Stalling: The engine may stall unexpectedly while driving, leading to safety concerns.
- Check Engine Light: The illumination of the check engine light on the dashboard is a common symptom when this code is triggered.
- Reduced Engine Performance: The vehicle may exhibit reduced power, acceleration issues, or erratic engine behavior.
- Electrical Component Malfunctions: Other electrical components, such as lights or dashboard indicators, may behave erratically due to power supply issues.
How to Fix P0687 2015 GMC Sierra
- Visual Inspection: Begin with a thorough visual inspection of the wiring and connectors associated with the ECM power relay. Look for signs of damage, corrosion, or loose connections.
- Test the Power Relay: Use a multimeter to test the ECM power relay for proper operation. Replace the relay if it is found to be defective.
- Check Wiring Harness: Inspect the wiring harness for any signs of wear, fraying, or short circuits. Repair or replace any damaged wiring as necessary.
- Scan for Additional Codes: Use an OBD-II scanner to check for any additional diagnostic trouble codes that may provide further insight into the issue.
- ECM Testing: If all other components check out, consider testing or replacing the ECM to ensure it is functioning correctly.
Cost to Fix P0687 2015 GMC Sierra
The cost to repair the P0687 code can vary widely based on the specific diagnosis and repairs needed. On average, you might expect to pay between $150 and $500 for parts and labor. This estimate includes the cost of a new power relay, any necessary wiring repairs, and labor costs, which typically range from $80 to $150 per hour.
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Frequently Asked Questions about P0687 2015 GMC Sierra Code
1. What does the OBDII code P0687 mean on a 2015 GMC Sierra?
The P0687 code indicates an issue with the Engine Control Module (ECM) Power Relay Control Circuit being stuck in a high voltage state.
2. What are the common symptoms of the P0687 code in a 2015 GMC Sierra?
Symptoms may include a no-start condition, engine stalling, poor performance, or the check engine light being illuminated.
3. What causes the P0687 code on a 2015 GMC Sierra?
Common causes include a faulty ECM power relay, damaged wiring or connectors in the power relay circuit, a blown fuse, or, in rare cases, a failing ECM.
4. How do I diagnose the P0687 code on my GMC Sierra?
Start by inspecting the ECM power relay, fuses, and associated wiring for damage or corrosion. Use a multimeter to check for proper voltage and continuity in the circuit.
5. Can I still drive my 2015 GMC Sierra with the P0687 code?
Driving with this code is not recommended, as it could lead to engine stalling or failure to start, potentially leaving you stranded.
6. How do I fix the P0687 code on a 2015 GMC Sierra?
Repairs may include replacing a faulty ECM power relay, repairing damaged wiring or connectors, replacing a blown fuse, or reprogramming or replacing the ECM if necessary.
7. How much does it cost to fix the P0687 code on a GMC Sierra?
Repair costs can range from $50 to $200 for components like relays or wiring repairs, while replacing the ECM could cost $500 to $1,500, including programming.
8. Could a dead battery cause the P0687 code on my 2015 GMC Sierra?
A weak or dead battery could contribute to electrical issues, but the P0687 code specifically points to a problem in the ECM power relay control circuit.
9. What tools do I need to diagnose the P0687 code on my GMC Sierra?
You’ll need a scan tool, multimeter, and possibly a wiring diagram for the ECM power relay circuit to perform a thorough diagnosis.
10. Does the P0687 code require ECM replacement on a 2015 GMC Sierra?
ECM replacement is rare and should only be considered after verifying the relay, wiring, and fuses are all functioning properly.
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