Engine-Codes.com
Engine-Codes – Buick – P0685 Buick

P0685 Buick Code - Engine Control Module Power Relay Control Circuit Open

Quick Answer

The P0685 Buick code indicates a problem with the Engine Control Module (ECM) Power Relay Control Circuit being open, meaning that there is a lack of continuity in the circuit that controls the power relay for the ECM. Common causes include Corrosion or damage to the wiring or connectors in the ECM power relay control circuit, Loose or poor connections in the circuit, A faulty 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
P0685 Buick indicates Engine Control Module Power Relay Control Circuit Open.
Common causes
Common causes include Corrosion or damage to the wiring or connectors in the ECM power relay control circuit, Loose or poor connections in the circuit, A faulty 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.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0685 Buick Description

The P0685 Buick code indicates a problem with the Engine Control Module (ECM) Power Relay Control Circuit being open, meaning that there is a lack of continuity in the circuit that controls the power relay for the ECM. The ECM is a crucial component of the vehicle's engine management system, responsible for controlling various functions such as fuel injection, ignition timing, and emissions control. When the power relay control circuit is open, it can lead to a loss of power to the ECM, causing a range of performance issues and potentially leading to the vehicle stalling or not starting at all.

OBDII Code P0685 Buick - Engine Control Module Power Relay Control Circuit Open
P0685 Buick Code - Engine Control Module Power Relay Control Circuit Open

Common Causes of P0685 Buick

  1. Corrosion or damage to the wiring or connectors in the ECM power relay control circuit.
  2. Loose or poor connections in the circuit.
  3. A faulty ECM power relay.
  4. Issues with the ECM itself.
  5. Electrical system malfunctions or shorts.

Symptoms of P0685 Buick

  1. Engine misfires or hesitation during acceleration.
  2. Difficulty starting the vehicle or intermittent stalling.
  3. Reduced fuel efficiency and increased emissions.
  4. Illumination of the Check Engine Light.
  5. Loss of power or rough idling.

How to Fix P0685 Buick

  1. Begin by conducting a thorough inspection of the wiring, connectors, and relay associated with the ECM power relay control circuit.
  2. Test the power relay for proper functionality and replace if necessary.
  3. Check the ECM for any signs of damage or malfunction and address as needed.
  4. Repair or replace any damaged wiring or connectors in the circuit.
  5. Clear the diagnostic trouble codes and perform a test drive to ensure the issue has been resolved.

Cost to Fix P0685 Buick

The typical repair costs for addressing the P0685 Buick code can vary depending on the specific cause of the issue and the labor rates in your area. On average, you can expect to pay anywhere from $150 to $400 for parts and labor. Keep in mind that diagnostic time and labor rates can impact the final cost, so it's advisable to contact local auto repair shops for a more accurate estimate. Remember that rates may differ based on location, vehicle make and model, and the complexity of the repair.

What does this mean?

Tech Notes for P0685 Buick

Check all the Engine Control Module (ECM) fuses, if the fuses are OK, then replacing the ECM relay should take care of the problem.

Need more information about the P0685 Buick code?

Need more information on how to fix the P0685 Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0685 Buick 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 P0685 Buick Code

1. What are the common symptoms of OBDII code P0685 in a Buick related to the Engine Control Module Power Relay Control Circuit Open?

- Common symptoms include engine stalling, difficulty starting the vehicle, and in some cases, the engine may not start at all.

2. What are the possible causes of OBDII code P0685 in a Buick related to the Engine Control Module Power Relay Control Circuit Open?

- Possible causes include a faulty engine control module power relay, damaged wiring or connectors in the circuit, or a defective engine control module itself.

3. How can I diagnose OBDII code P0685 in a Buick related to the Engine Control Module Power Relay Control Circuit Open?

- Diagnosis typically involves checking the power relay, inspecting the wiring and connectors for any damage, and testing the engine control module for proper function.

4. What are some repair tips for resolving OBDII code P0685 in a Buick related to the Engine Control Module Power Relay Control Circuit Open?

- Repair tips may include replacing the faulty power relay, repairing any damaged wiring or connectors in the circuit, or replacing the engine control module if necessary.

5. Can OBDII code P0685 in a Buick related to the Engine Control Module Power Relay Control Circuit Open cause any long-term damage to the vehicle?

- If left unresolved, this code can potentially lead to further damage to the engine control module or other related components, so it is important to address the issue promptly.

6. Is it safe to continue driving my Buick with OBDII code P0685 related to the Engine Control Module Power Relay Control Circuit Open?

- It is not recommended to continue driving the vehicle with this code present, as it can cause potential reliability issues and may lead to more severe problems if not addressed.

7. How much does it typically cost to repair OBDII code P0685 in a Buick related to the Engine Control Module Power Relay Control Circuit Open?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from a few hundred to a thousand dollars, including parts and labor.

8. Can I reset the OBDII code P0685 in my Buick related to the Engine Control Module Power Relay Control Circuit Open on my own?

- While you can clear the code with an OBDII scanner, it is important to diagnose and address the underlying issue causing the code before resetting it to prevent it from reoccurring.

9. Will disconnecting the battery reset OBDII code P0685 in my Buick related to the Engine Control Module Power Relay Control Circuit Open?

- Disconnecting the battery may clear the code temporarily, but it is not a permanent solution as the underlying issue still needs to be diagnosed and repaired.

10. Can a mechanic easily fix OBDII code P0685 in a Buick related to the Engine Control Module Power Relay Control Circuit Open?

- A qualified mechanic with experience in automotive electrical systems should be able to diagnose and repair this issue effectively to resolve the code.

Discuss the causes and fixes for P0685 Buick OBDII Code

Submit a New Comment

Code P0685 Buick comments

No comments found for this page.