AutoCodes – Mercury – P0685 Mercury

P0685 Mercury Code - Powertrain Control Module Power Relay Control Circuit Open

Quick Answer

This DTC sets when the ignition switch position run circuit indicates the ignition is in the OFF, ACC, or LOCK position, and the amount of time the Powertrain Control Module (PCM) remains powered through the PCM power relay exceeds a predetermined amount of time. Common causes include Faulty Powertrain Control Module (PCM) Power Relay, PCM Power Relay harness is open or shorted, PCM Power Relay circuit poor electrical connection. 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 Mercury indicates Powertrain Control Module Power Relay Control Circuit Open.
Common causes: Common causes include Faulty Powertrain Control Module (PCM) Power Relay, PCM Power Relay harness is open or shorted, PCM Power Relay circuit poor electrical connection.
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 2,210

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 May 05, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0685 Mercury Description

OBDII Code P0685 Mercury - Powertrain Control Module Power Relay Control Circuit Open - AutoCodes.com — P0685 Mercury Code - Powertrain Control Module Power Relay Control Circuit Open

What does this mean?

What are the Possible Causes of the DTC P0685 Mercury?

Faulty Powertrain Control Module (PCM) Power Relay
PCM Power Relay harness is open or shorted
PCM Power Relay circuit poor electrical connection
Blown PCM fuse
Faulty PCM

How to Fix the DTC P0685 Mercury?

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 does this mean?

Code Tech Notes

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0685 Mercury 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 P0685 Mercury code?

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

Need Help with the Code?

Get the P0685 Mercury 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 Mercury Code

1. What are common symptoms of OBDII code P0685 in a Mercury vehicle?

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

2. What does the OBDII code P0685 on a Mercury indicate?

- The code P0685 indicates a problem with the Powertrain Control Module (PCM) power relay control circuit being open.

3. What are possible causes of the P0685 code in a Mercury?

- Possible causes include a faulty power relay, damaged wiring or connectors in the power relay circuit, or issues with the PCM itself.

4. How can I diagnose the P0685 code in my Mercury?

- Diagnosing the code involves inspecting the power relay, checking the wiring and connectors for any damage, and testing the PCM for proper functioning.

5. Can I still drive my Mercury with the P0685 code present?

- It is not recommended to drive the vehicle with the P0685 code present, as it can lead to more serious issues and potential engine damage.

6. How can I repair the P0685 code in my Mercury?

- Repairing the P0685 code may involve replacing the faulty power relay, repairing or replacing damaged wiring or connectors, or reprogramming the PCM.

7. Is it possible to reset the P0685 code in a Mercury without fixing the underlying issue?

- While you can clear the code temporarily, it will likely reappear until the underlying issue with the power relay control circuit is resolved.

8. Can a DIY enthusiast fix the P0685 code in a Mercury?

- Depending on your skills and experience, you may be able to diagnose and repair the P0685 code yourself, but it is recommended to seek professional help for accurate diagnosis and repair.

9. How much does it cost to repair the P0685 code in a Mercury at a mechanic?

- The cost of repairing the P0685 code can vary depending on the underlying issue, but it may range from $100 to $500 or more, including parts and labor.

10. Will fixing the P0685 code improve the performance of my Mercury?

- Yes, resolving the P0685 code will help restore proper engine function, improve performance, and prevent potential damage to other components in the vehicle.