AutoCodes – Chevrolet – P0686 Chevrolet

P0686 Chevrolet Code - Engine Control Module Power Relay Control Circuit Low

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: P0686 Chevrolet indicates Engine Control Module Power Relay Control Circuit Low.
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 5,342

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 P0686 Chevrolet 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 P0686 Chevrolet - Engine Control Module Power Relay Control Circuit Low - AutoCodes.com — P0686 Chevrolet Code - Engine Control Module Power Relay Control Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0686 Chevrolet?

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 P0686 Chevrolet?

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 P0686 Chevrolet 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 P0686 Chevrolet code?

Need more information on how to fix the P0686 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0686 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P0686 2014 Chevrolet Silverado — Engine Control Module Power Relay Control Circuit Low
P0686 2015 Chevrolet Silverado — Engine Control Module Power Relay Control Circuit Low
P0686 2016 Chevrolet Silverado — Engine Control Module Power Relay Control Circuit Low
P0686 2017 Chevrolet Silverado — Engine Control Module Power Relay Control Circuit Low
P0686 2018 Chevrolet Silverado — Engine Control Module Power Relay Control Circuit Low

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 P0686 Chevrolet Code

1. What are the common symptoms of OBDII code P0686 in a Chevrolet?

- Common symptoms include engine stalling, poor engine performance, difficulty starting the vehicle, and illuminated check engine light.

2. What usually causes the OBDII code P0686 in a Chevrolet?

- The code is typically caused by a faulty engine control module power relay or issues with the power relay control circuit being low.

3. How can I diagnose the OBDII code P0686 in my Chevrolet?

- Diagnosing the code involves checking the engine control module power relay, inspecting the power relay control circuit for any faults, and testing the relay's functionality.

4. Can a DIY enthusiast repair the OBDII code P0686 in a Chevrolet?

- While some enthusiasts may have the skills to diagnose and replace the faulty relay, it is recommended to seek professional help for accurate diagnosis and repair.

5. Is it safe to continue driving with the OBDII code P0686 in a Chevrolet?

- It is not recommended to drive the vehicle with this code as it can lead to further engine issues and potential safety hazards. It is best to address the problem promptly.

6. How much does it typically cost to repair the OBDII code P0686 in a Chevrolet?

- The cost of repair can vary depending on the extent of the issue and the labor rates in your area. It is advisable to get a few quotes from reputable mechanics.

7. Are there any preventive measures to avoid OBDII code P0686 in a Chevrolet?

- Regular maintenance of the vehicle's electrical system, including checking and replacing relays as needed, can help prevent issues that trigger this code.

8. Can a weak battery or alternator cause the OBDII code P0686 in a Chevrolet?

- A weak battery or alternator can sometimes lead to electrical issues that trigger this code. It is advisable to ensure the battery and alternator are in good condition.

9. Will resetting the OBDII code P0686 in a Chevrolet make it go away permanently?

- Resetting the code may temporarily turn off the check engine light, but it will reappear if the underlying issue causing the code is not addressed and fixed.

10. Can a bad ground connection contribute to the OBDII code P0686 in a Chevrolet?

- Yes, a bad ground connection can disrupt the power relay control circuit and lead to the triggering of this code. It is essential to check and maintain proper ground connections.