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Engine-Codes – GMC – P0687 2016 GMC Sierra

P0687 2016 GMC Sierra Code - Engine Control Module Power Relay Control Circuit High

Quick Answer

The P0687 diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a problem with the Engine Control Module (ECM) power relay control circuit being high. Common causes include Faulty ECM power relay, Wiring issues in the power relay control circuit, Poor electrical connections. 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 Faulty ECM power relay, Wiring issues in the power relay control circuit, Poor electrical connections.
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 13, 2024
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Code P0687 2016 GMC Sierra Description

The P0687 diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a problem with the Engine Control Module (ECM) power relay control circuit being high. This means that the ECM is not receiving the expected voltage signal from the power relay control circuit. The ECM plays a crucial role in controlling various engine functions, such as fuel injection, ignition timing, and emissions systems. When the power relay control circuit is high, it can lead to issues with the ECM's ability to properly regulate these functions, resulting in poor engine performance, decreased fuel efficiency, and potential drivability problems.

OBDII Code P0687 2016 GMC Sierra - Engine Control Module Power Relay Control Circuit High
P0687 2016 GMC Sierra Code - Engine Control Module Power Relay Control Circuit High

Common Causes of P0687 2016 GMC Sierra

  1. Faulty ECM power relay
  2. Wiring issues in the power relay control circuit
  3. Poor electrical connections
  4. ECM software issues
  5. Battery voltage irregularities

Symptoms of P0687 2016 GMC Sierra

  1. Check Engine Light illuminated
  2. Rough idling or stalling
  3. Hesitation during acceleration
  4. Decreased fuel efficiency
  5. Engine misfires

How to Fix P0687 2016 GMC Sierra

  1. Diagnose the issue by using a scan tool to verify the P0687 code and inspecting the power relay control circuit for any visible damage.
  2. Test the ECM power relay to ensure it is functioning correctly. Replace the relay if necessary.
  3. Check the wiring and connections in the power relay control circuit for any signs of damage or corrosion. Repair or replace as needed.
  4. Clear the DTC and reset the ECM to see if the code returns. Test drive the vehicle to verify that the issue has been resolved.
  5. If the problem persists, further diagnostics may be required to pinpoint the exact cause, such as checking for voltage irregularities or software updates for the ECM.

Cost to Fix P0687 2016 GMC Sierra

The typical repair costs for addressing a P0687 code on a 2016 GMC Sierra can vary depending on the specific cause of the issue. In general, replacing a faulty ECM power relay or repairing wiring/connectors can range from $100 to $300, including parts and labor. Additional diagnostic time and potential software updates may incur extra costs. It's important to note that labor rates at auto repair shops can vary, with hourly rates typically ranging between $80 and $150. Factors such as location, vehicle make and model, and engine type can also impact the overall repair costs. For a more accurate estimate, it's recommended to consult with local auto repair shops.

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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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