AutoCodes – GMC – P0687 2016 GMC Sierra

P0687 2016 GMC Sierra 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 2016 GMC Sierra 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 182

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 2016 GMC Sierra 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 2016 GMC Sierra - Engine Control Module Power Relay Control Circuit High - AutoCodes.com — P0687 2016 GMC Sierra Code - Engine Control Module Power Relay Control Circuit High

What does this mean?

What are the Possible Causes of the DTC P0687 2016 GMC Sierra?

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 2016 GMC Sierra?

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 2016 GMC Sierra 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 2016 GMC Sierra code?

Need more information on how to fix the P0687 2016 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0687 2016 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 2016 GMC Sierra Code

1. What does the OBDII code P0687 mean on a 2016 GMC Sierra?

P0687 indicates an issue with the Engine Control Module (ECM) power relay control circuit, specifically that the voltage is higher than expected.

2. What are the common symptoms of P0687 in a 2016 GMC Sierra?

Symptoms may include difficulty starting the engine, engine stalling, illuminated check engine light, and reduced engine performance.

3. What causes the P0687 code to appear in a GMC Sierra?

Common causes include a faulty ECM power relay, damaged wiring or connectors in the circuit, a blown fuse, or a malfunctioning ECM.

4. Can a bad battery cause the P0687 code on a 2016 GMC Sierra?

Yes, a weak or failing battery that causes voltage fluctuations can contribute to this code.

5. How do I diagnose the P0687 code on my GMC Sierra?

Start by checking the ECM power relay, inspecting wiring and connectors for damage, verifying fuse integrity, and testing the battery and charging system.

6. How serious is the P0687 code on a 2016 GMC Sierra?

It can be serious as it may lead to engine stalling or failure to start, potentially leaving you stranded. Prompt diagnosis and repair are recommended.

7. Can I drive my 2016 GMC Sierra with the P0687 code?

Driving with this code is not recommended as the engine may stall unexpectedly, posing a safety risk.

8. How do I fix the P0687 code on my GMC Sierra?

Repairs may include replacing the ECM power relay, repairing or replacing damaged wiring, replacing a blown fuse, or in rare cases, replacing the ECM.

9. How much does it cost to fix the P0687 code on a 2016 GMC Sierra?

Repair costs vary but typically range from $100 to $300 depending on the specific issue, such as replacing the relay or repairing wiring.

10. Can a software update fix the P0687 code on a GMC Sierra?

While unlikely, in rare cases, an ECM software update may resolve false detections of this code. Consult with a dealer or qualified technician.

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