AutoCodes – Buick – P0687 Buick

P0687 Buick 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 Buick 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 1,489

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 18, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0687 Buick 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 Buick - Engine Control Module Power Relay Control Circuit High - AutoCodes.com — P0687 Buick Code - Engine Control Module Power Relay Control Circuit High

What does this mean?

What are the Possible Causes of the DTC P0687 Buick?

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 Buick?

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 Buick 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 Buick code?

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Need Help with the Code?

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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 Buick Code

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

- Common symptoms include engine stalling, rough idling, poor acceleration, and potential difficulty starting the vehicle.

2. What does the OBDII code P0687 Buick indicate?

- This code indicates a problem with the engine control module power relay control circuit being high.

3. What are the possible causes of OBDII code P0687 in a Buick?

- Possible causes include a faulty engine control module power relay, damaged wiring or connectors, or a malfunctioning engine control module itself.

4. How can I diagnose the cause of OBDII code P0687 in my Buick?

- Use a diagnostic scanner to retrieve the specific fault codes, inspect the engine control module power relay, check for any damaged wiring or connectors, and test the engine control module functionality.

5. Can I still drive my Buick with OBDII code P0687 present?

- It is not recommended to drive your vehicle with this code present, as it can lead to further engine issues and potential safety hazards.

6. How can I repair OBDII code P0687 in my Buick?

- Repair options include replacing the faulty engine control module power relay, repairing damaged wiring or connectors, or replacing the engine control module itself if necessary.

7. Is it safe to reset the OBDII code P0687 in my Buick using a scanner?

- While you can reset the code using a scanner, it is important to address the underlying issue causing the fault code to prevent further problems.

8. Can a DIY enthusiast fix OBDII code P0687 in a Buick?

- Depending on your skill level and access to tools, you may be able to diagnose and repair this code yourself, but it is recommended to consult a professional for accurate diagnosis and repair.

9. How much can I expect to pay for repairing OBDII code P0687 in a Buick?

- The cost of repair can vary depending on the cause of the issue and whether you choose to do the repair yourself or take it to a mechanic. Costs can range from a few hundred to over a thousand dollars.

10. Are there any preventive measures to avoid OBDII code P0687 in a Buick?

- Regular maintenance checks, including inspecting and maintaining the engine control module power relay and related components, can help prevent issues that lead to this code.