AutoCodes – Audi – P0685 Audi

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

Quick Answer

The Engine Control Module (ECM) monitors the power inputs. Common causes include Faulty Engine Control Module (ECM) power relay, ECM power relay harness is open or shorted, ECM 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 Audi indicates Engine Control Module Power Relay Control Circuit Open.
Common causes: Common causes include Faulty Engine Control Module (ECM) power relay, ECM power relay harness is open or shorted, ECM 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 21,566

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 Audi Description

The Engine Control Module (ECM) monitors the power inputs. The ECM sets the OBDII code when the ECM remains powered up after the ignition switch has been turned OFF.

OBDII Code P0685 Audi - Engine Control Module Power Relay Control Circuit Open - AutoCodes.com — P0685 Audi Code - Engine Control Module Power Relay Control Circuit Open

What does this mean?

What are the Possible Causes of the DTC P0685 Audi?

Faulty Engine Control Module (ECM) power relay
ECM power relay harness is open or shorted
ECM power relay circuit poor electrical connection
Blown ECM fuse
Faulty ECM

How to Fix the DTC P0685 Audi?

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 Audi 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.

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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 Audi Code

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

- Common symptoms include engine stalling, difficulty starting the vehicle, and illuminated check engine light.

2. What are the possible causes of OBDII code P0685 in an Audi?

- Possible causes include a faulty engine control module (ECM), a damaged power relay, loose or corroded electrical connections, or a wiring issue.

3. How can I diagnose the Engine Control Module Power Relay Control Circuit Open issue in my Audi?

- To diagnose P0685, it's recommended to perform a visual inspection of the power relay and associated wiring, check for loose connections, and use a multimeter to test the relay's functionality.

4. Can I drive my Audi with OBDII code P0685 present?

- It is not recommended to drive your Audi with code P0685 present, as it can lead to more severe issues like engine failure or electrical problems.

5. How can I repair OBDII code P0685 in my Audi?

- Repairing P0685 typically involves replacing a faulty power relay, repairing damaged wiring, or replacing the engine control module if necessary.

6. Are there any DIY tips for fixing OBDII code P0685 in my Audi?

- DIY tips include checking and cleaning electrical connections, inspecting and replacing damaged wiring, and ensuring the power relay is securely in place.

7. Is it necessary to reset the OBDII code P0685 after repairs are completed on my Audi?

- Yes, it is important to reset the code using an OBDII scanner after repairs to clear the fault code and turn off the check engine light.

8. Can a low battery voltage cause OBDII code P0685 to trigger in an Audi?

- Yes, low battery voltage can potentially cause code P0685 to trigger due to insufficient power supply to the engine control module and power relay.

9. What are the long-term effects of ignoring OBDII code P0685 in an Audi?

- Ignoring code P0685 can lead to more severe electrical issues, engine performance problems, and potential damage to other components in the vehicle.

10. Is it recommended to seek professional help for diagnosing and repairing OBDII code P0685 in my Audi?

- Yes, it is advisable to seek help from a qualified mechanic or dealership specializing in Audi vehicles for accurate diagnosis and proper repair of code P0685 to ensure safety and reliability.