AutoCodes – GMC – P0687 GMC

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

Quick Answer

The powertrain relay is a normally open relay. Common causes include Weak battery, Low voltage while cranking, Faulty Engine Control Module (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: P0687 GMC indicates Engine Control Module Power Relay Control Circuit High.
Common causes: Common causes include Weak battery, Low voltage while cranking, Faulty Engine Control Module (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 Popularity 1,498

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 19, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0687 GMC Description

The powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The Engine Control Module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an Output Driver Module (ODM). The ODM output control is configured to operate as a low side driver for the powertrain relay. The ODM for the powertrain relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. When the ECM commands the powertrain relay ON, ignition 1 voltage is supplied to the ECM, and to several additional circuits.

OBDII Code P0687 GMC - Engine Control Module Power Relay Control Circuit High - AutoCodes.com — P0687 GMC Code - Engine Control Module Power Relay Control Circuit High

What does this mean?

What are the Possible Causes of the DTC P0687 GMC?

Weak battery
Low voltage while cranking
Faulty Engine Control Module (ECM) power relay
ECM power relay harness is open or shorted
ECM power relay circuit poor electrical connection
Blown ECM fuse
Faulty ECM

How to Fix the DTC P0687 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0687 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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

P0687 2014 GMC Sierra — Engine Control Module Power Relay Control Circuit High
P0687 2015 GMC Sierra — Engine Control Module Power Relay Control Circuit High
P0687 2016 GMC Sierra — Engine Control Module Power Relay Control Circuit High
P0687 2017 GMC Sierra — Engine Control Module Power Relay Control Circuit High
P0687 2018 GMC Sierra — Engine Control Module Power Relay Control Circuit High

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.