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P0685 2008 Honda Accord Code - Engine Control Module Power Relay Control Circuit Open

Quick Answer

The P0685 code on a 2008 Honda Accord indicates that there is an issue with the engine control module power relay control circuit being open. Common causes include Faulty power relay, Wiring issues or loose connections in the power relay control circuit, ECM malfunction. 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 2008 Honda Accord indicates Engine Control Module Power Relay Control Circuit Open.
Common causes
Common causes include Faulty power relay, Wiring issues or loose connections in the power relay control circuit, ECM malfunction.
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 13, 2024
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Code P0685 2008 Honda Accord Description

The P0685 code on a 2008 Honda Accord indicates that there is an issue with the engine control module power relay control circuit being open. This means that the power relay that controls the engine control module is not functioning properly, which can lead to a variety of performance issues in the vehicle. The engine control module (ECM) is a crucial component that manages various functions of the engine, such as fuel injection, ignition timing, and emissions control. The power relay is responsible for supplying power to the ECM, allowing it to function correctly.

OBDII Code P0685 2008 Honda Accord - Engine Control Module Power Relay Control Circuit Open
P0685 2008 Honda Accord Code - Engine Control Module Power Relay Control Circuit Open

Common Causes of P0685 2008 Honda Accord

  1. Faulty power relay
  2. Wiring issues or loose connections in the power relay control circuit
  3. ECM malfunction
  4. Corrosion or damage to electrical components
  5. Poor electrical ground connections

Symptoms of P0685 2008 Honda Accord

  1. Engine misfires or rough idling
  2. Reduced fuel efficiency
  3. Stalling or difficulty starting the vehicle
  4. Check Engine Light illuminated
  5. Limited engine performance

How to Fix P0685 2008 Honda Accord

  1. Begin by diagnosing the power relay and control circuit using a multimeter to check for continuity and proper voltage.
  2. Inspect the wiring and connections for any signs of damage, corrosion, or loose connections. Repair or replace as needed.
  3. Test the ECM to ensure it is functioning correctly. If necessary, replace the ECM.
  4. Reset the fault codes and test drive the vehicle to ensure the issue has been resolved.
  5. Clear the code and recheck for any recurring issues.

Cost to Fix P0685 2008 Honda Accord

The typical repair costs for addressing the P0685 code on a 2008 Honda Accord can range from $150 to $500, depending on the specific cause of the issue and the cost of parts and labor. It's important to note that the diagnosis time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate. Keep in mind that rates may be higher at dealerships or in metropolitan areas, while independent shops may offer more affordable options.

What does this mean?

Tech Notes for P0685 2008 Honda Accord

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 2008 Honda Accord Code

1. What are the common symptoms of OBDII code P0685 in a 2008 Honda Accord?

- Common symptoms include engine stalling, difficulty starting the vehicle, and the illumination of the Check Engine light.

2. What causes the Engine Control Module Power Relay Control Circuit Open code (P0685) in a 2008 Honda Accord?

- The code P0685 is typically caused by a faulty engine control module power relay or issues with the wiring in the control circuit.

3. How can I diagnose the OBDII code P0685 on my 2008 Honda Accord?

- To diagnose the code P0685, you can use a diagnostic scanner to read the trouble codes, then inspect the engine control module power relay and related wiring for any visible damage.

4. Can I drive my 2008 Honda Accord with the P0685 code present?

- It is not recommended to drive your vehicle with the P0685 code active, as it can lead to potential engine performance issues and further damage if left unresolved.

5. How can I repair the Engine Control Module Power Relay Control Circuit Open code in my 2008 Honda Accord?

- The repair typically involves replacing the faulty engine control module power relay and addressing any wiring issues in the control circuit.

6. Is it possible to reset the P0685 code in a 2008 Honda Accord without making any repairs?

- While you can clear the code using a diagnostic scanner, it is crucial to address the underlying issue causing the code to prevent further problems.

7. Can a DIY enthusiast fix the P0685 code in a 2008 Honda Accord?

- Depending on your expertise, you may be able to replace the engine control module power relay yourself, but if you are unsure, it is best to consult a professional mechanic.

8. How much does it cost to repair the P0685 code in a 2008 Honda Accord at a dealership?

- The cost of repairing the P0685 code at a dealership can vary but typically includes the cost of parts, labor, and any diagnostic fees.

9. Will the P0685 code in a 2008 Honda Accord affect fuel efficiency?

- Yes, the P0685 code can potentially affect fuel efficiency due to engine performance issues caused by the faulty engine control module power relay.

10. How long does it take to repair the P0685 code in a 2008 Honda Accord?

- The repair time for the P0685 code can vary depending on the extent of the issue, but it typically takes a few hours to replace the engine control module power relay and address wiring problems.

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