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P0687 2015 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 2015 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 194
How popular is this code, among other codes? Low
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Table of contents Created and updated by William Orellana on Jul 19, 2022
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Code P0687 2015 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 2015 GMC Sierra - Engine Control Module Power Relay Control Circuit High - AutoCodes.com
P0687 2015 GMC Sierra Code - Engine Control Module Power Relay Control Circuit High
What does this mean?

What are the Possible Causes of the DTC P0687 2015 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 2015 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 2015 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 2015 GMC Sierra code?

Need more information on how to fix the P0687 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0687 2015 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 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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