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

Quick Answer

The P0685 Pontiac code indicates that there is an issue with the Engine Control Module (ECM) Power Relay Control Circuit being open. Common causes include Faulty ECM power relay, Loose or corroded electrical connections, Wiring harness issues. 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 Pontiac indicates Engine Control Module Power Relay Control Circuit Open.
Common causes
Common causes include Faulty ECM power relay, Loose or corroded electrical connections, Wiring harness issues.
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 10, 2024
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Code P0685 Pontiac Description

The P0685 Pontiac code indicates that there is an issue with the Engine Control Module (ECM) Power Relay Control Circuit being open. The ECM power relay is responsible for providing power to the engine control module, which is a critical component in managing various engine functions such as fuel injection, ignition timing, and emissions control. When the control circuit is open, it means that there is a break or interruption in the circuit that is preventing the relay from functioning properly. This can lead to a loss of power to the ECM, resulting in the engine not running efficiently or possibly not starting at all.

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

Common Causes of P0685 Pontiac

  1. Faulty ECM power relay
  2. Loose or corroded electrical connections
  3. Wiring harness issues
  4. ECM failure
  5. Electrical system problems

Symptoms of P0685 Pontiac

  1. Engine misfires or rough idling
  2. Difficulty starting the engine
  3. Reduced fuel efficiency
  4. Engine stalling
  5. Illumination of the Check Engine Light

How to Fix P0685 Pontiac

  1. Use a diagnostic tool to retrieve the trouble code and identify the specific issue with the ECM power relay control circuit.
  2. Inspect the ECM power relay and associated wiring for any visible damage or corrosion. Replace the relay if necessary.
  3. Check for loose or disconnected electrical connections and repair as needed.
  4. Test the circuit for continuity and proper voltage to ensure that power is reaching the ECM.
  5. Clear the trouble code from the ECM's memory and test drive the vehicle to verify that the issue has been resolved.

Cost to Fix P0685 Pontiac

The typical repair costs for addressing a P0685 Pontiac code can vary depending on the specific cause of the issue. In general, replacing a faulty ECM power relay can cost anywhere from $50 to $150, while addressing wiring or electrical problems may require additional labor and parts, potentially bringing the total repair cost to $200 - $500. It's important to note that the actual cost can vary based on factors such as the vehicle's make and model, the location of the repair shop, and the extent of the issue. Diagnostic time and labor rates at auto repair shops typically range from $80 to $150 per hour, with rates potentially higher at dealerships or in metropolitan areas. It's recommended to obtain a detailed estimate from a trusted mechanic before proceeding with the repair.

What does this mean?

Tech Notes for P0685 Pontiac

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

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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 P0685 Pontiac Code

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

The common symptoms include engine stalling, difficulty starting the vehicle, and illuminated Check Engine Light.

2. What are the possible causes of OBDII code P0685 indicating an Engine Control Module Power Relay Control Circuit Open in a Pontiac?

Possible causes include a faulty power relay, damaged wiring or connectors in the relay circuit, or a malfunctioning Engine Control Module.

3. How can I diagnose the cause of OBDII code P0685 in my Pontiac?

You can start by checking the power relay and its connections, testing the relay circuit for continuity, and inspecting the wiring harness for any signs of damage.

4. What are some tips for repairing OBDII code P0685 in a Pontiac?

Repair tips include replacing the faulty power relay, repairing any damaged wiring or connectors, or replacing the Engine Control Module if necessary.

5. Can I drive my Pontiac with OBDII code P0685 present?

It is not recommended to drive the vehicle with this code present as it can lead to potential issues with starting the engine and overall performance.

6. How much does it typically cost to repair OBDII code P0685 in a Pontiac?

The cost of repairs can vary depending on the underlying cause, but it may range from around $100 to $500, including parts and labor.

7. Will resetting the Check Engine Light make OBDII code P0685 go away in a Pontiac?

Resetting the Check Engine Light may temporarily turn it off, but if the underlying issue causing the code is not addressed, it is likely to reappear.

8. Can a DIY enthusiast fix OBDII code P0685 in a Pontiac?

If you have experience with automotive repairs and diagnostics, you may be able to fix this issue yourself by following repair guides and using the right tools.

9. Is OBDII code P0685 a serious problem in a Pontiac?

While it may not pose an immediate danger, ignoring this code can lead to more severe issues with the engine's performance and overall reliability.

10. How long does it take to repair OBDII code P0685 in a Pontiac?

The repair time can vary depending on the specific cause of the code, but it typically takes a few hours to diagnose and fix the issue.

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