Engine-Codes.com
Engine-Codes – GMC – P0687 GMC

P0687 GMC Code - Engine Control Module Power Relay Control Circuit High

Quick Answer

The P0687 GMC code indicates a problem with the engine control module power relay control circuit being too high. Common causes include Faulty power relay, Damaged wiring or connectors in the power relay circuit, Malfunctioning 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
P0687 GMC indicates Engine Control Module Power Relay Control Circuit High.
Common causes
Common causes include Faulty power relay, Damaged wiring or connectors in the power relay circuit, Malfunctioning 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.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0687 GMC Description

The P0687 GMC code indicates a problem with the engine control module power relay control circuit being too high. The engine control module (ECM) is responsible for controlling various engine functions, such as fuel injection, ignition timing, and emissions control. The power relay control circuit is crucial for providing power to the ECM, and if this circuit is not functioning properly, it can lead to serious issues with the vehicle's performance.

OBDII Code P0687 GMC - Engine Control Module Power Relay Control Circuit High
P0687 GMC Code - Engine Control Module Power Relay Control Circuit High

Common Causes of P0687 GMC

  1. Faulty power relay
  2. Damaged wiring or connectors in the power relay circuit
  3. Malfunctioning ECM
  4. Corrosion or loose connections in the power relay circuit
  5. Electrical issues such as short circuits or high resistance in the circuit

Symptoms of P0687 GMC

  1. Engine misfiring or rough idle
  2. Difficulty starting the engine
  3. Decreased fuel efficiency
  4. Engine stalling
  5. Illuminated check engine light

How to Fix P0687 GMC

  1. Diagnose the issue by conducting a thorough inspection of the power relay circuit and ECM.
  2. Test the power relay to determine if it is functioning correctly. Replace the relay if necessary.
  3. Inspect the wiring and connectors in the power relay circuit for any damage or corrosion. Repair or replace as needed.
  4. Check the ECM for any signs of malfunction. Replace the ECM if it is found to be faulty.
  5. Clear the trouble codes and perform a test drive to ensure the issue has been resolved.

Cost to Fix P0687 GMC

The typical repair costs for addressing a P0687 GMC code can vary depending on the specific cause of the issue. On average, the cost of parts for this repair could range from $50 to $200, while labor costs could range from $100 to $300. It's important to note that these are rough estimates, and actual costs may vary based on factors such as the vehicle make and model, location, and the shop's labor rates. It's recommended to consult with a qualified mechanic for a more precise cost estimate.

Need more information about the P0687 GMC code?

Need more information on how to fix the P0687 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0687 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0687 GMC Code

1. What are the common symptoms of OBDII code P0687 in a GMC vehicle?

- Common symptoms include the engine stalling or not starting, poor engine performance, and the check engine light being illuminated.

2. What can cause the OBDII code P0687 in a GMC vehicle?

- The code P0687 is typically triggered by a faulty engine control module (ECM) power relay or issues with the relay control circuit.

3. How do I diagnose the OBDII code P0687 in my GMC vehicle?

- Diagnosing the code involves checking the ECM power relay, inspecting the relay control circuit for any damage or loose connections, and testing the relay's functionality.

4. What are some repair tips for fixing the OBDII code P0687 in a GMC vehicle?

- Repair tips include replacing the faulty ECM power relay, repairing any damaged wiring in the relay control circuit, and ensuring all connections are secure.

5. Can I drive my GMC vehicle with the OBDII code P0687?

- It is not recommended to drive your vehicle with the code P0687, as it can lead to potential engine performance issues and the risk of stalling while driving.

6. How much does it cost to repair the OBDII code P0687 in a GMC vehicle?

- The cost of repair can vary depending on the extent of the issue, but it typically involves replacing the ECM power relay, which can range from $100 to $300 including labor.

7. Will resetting the OBDII code P0687 make it go away permanently?

- Resetting the code temporarily may turn off the check engine light, but if the underlying issue causing the code is not addressed, it is likely to return.

8. Can a DIY enthusiast fix the OBDII code P0687 in a GMC vehicle?

- While some DIY enthusiasts may be able to diagnose and repair the issue themselves, it is recommended to seek professional help to ensure the problem is properly addressed.

9. Is the OBDII code P0687 a serious issue in a GMC vehicle?

- Yes, the code P0687 indicating a problem with the ECM power relay control circuit is a serious issue that should be addressed promptly to avoid potential engine damage or safety hazards.

10. How long does it take to repair the OBDII code P0687 in a GMC vehicle?

- The repair time can vary depending on the exact cause of the issue and the availability of parts, but it typically takes a few hours to complete the repair.

Discuss the causes and fixes for P0687 GMC OBDII Code

Submit a New Comment

Code P0687 GMC comments

No comments found for this page.