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Engine-Codes – Generic – P0686

P0686 Code - Engine Control Module Power Relay Control Circuit Low

Quick Answer

The diagnostic trouble code P0686 indicates that there is an issue with the Engine Control Module (ECM) power relay control circuit being too low. Common causes include Faulty ECM power relay, Damaged wiring or connectors in the power relay circuit, Malfunctioning ECM. 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 indicates Engine Control Module Power Relay Control Circuit Low.
Common causes
Common causes include Faulty ECM power relay, Damaged wiring or connectors in the power relay circuit, Malfunctioning ECM.
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 06, 2024
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Code P0686 Description

The diagnostic trouble code P0686 indicates that there is an issue with the Engine Control Module (ECM) power relay control circuit being too low. The ECM power relay is responsible for supplying power to the ECM, which is the brain of the vehicle's engine management system. When the power relay control circuit is low, it means that there is a problem with the power supply to the ECM, which can lead to various performance issues.

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

Common Causes of P0686

  1. Faulty ECM power relay
  2. Damaged wiring or connectors in the power relay circuit
  3. Malfunctioning ECM
  4. Corrosion in the power relay circuit
  5. Electrical issues related to the power supply

Symptoms of P0686

  1. Engine misfires
  2. Stalling
  3. Rough idling
  4. Check engine light illuminated
  5. Loss of power

How to Fix P0686

  1. Diagnose the root cause of the issue using a diagnostic scanner
  2. Inspect the ECM power relay, wiring, and connectors for any damage or corrosion
  3. Replace the faulty ECM power relay if necessary
  4. Repair or replace damaged wiring or connectors
  5. Clear the trouble code and test drive the vehicle to ensure the issue has been resolved

Cost to Fix P0686

The cost of repairing the Engine Control Module Power Relay Control Circuit Low issue can vary depending on the specific cause of the problem and the labor rates at the auto repair shop. On average, the repair costs can range from $100 to $300 for parts and labor. It's important to consider that diagnostic time and labor rates may vary, so it's recommended to check with local auto repair shops for a more accurate estimate.

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Code P0686 Information for Specific Makes

  • P0686 Audi — Engine Control Module Power Relay Control Circuit Low
  • P0686 BMW — Engine Control Module Power Relay Control Circuit Low
  • P0686 Buick — Engine Control Module Power Relay Control Circuit Low
  • P0686 Cadillac — Engine Control Module Power Relay Control Circuit Low
  • P0686 Chevrolet — Engine Control Module Power Relay Control Circuit Low
  • P0686 Chrysler — Engine Control Module Power Relay Control Circuit Low
  • P0686 Dodge — Engine Control Module Power Relay Control Circuit Low
  • P0686 Ford — Engine Control Module Power Relay Control Circuit Low
  • P0686 GMC — Engine Control Module Power Relay Control Circuit Low
  • P0686 Isuzu — Engine Control Module Power Relay Control Circuit Low
  • P0686 Jeep — Engine Control Module Power Relay Control Circuit Low
  • P0686 Lincoln — Engine Control Module Power Relay Control Circuit Low
  • P0686 Mercury — Engine Control Module Power Relay Control Circuit Low
  • P0686 MINI — Engine Control Module Power Relay Control Circuit Low
  • P0686 Pontiac — Engine Control Module Power Relay Control Circuit Low
  • P0686 Saturn — Engine Control Module Power Relay Control Circuit Low
  • P0686 Suzuki — Engine Control Module Power Relay Control Circuit Low
  • P0686 Volkswagen — 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.

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