AutoCodes – Isuzu – P0685 Isuzu

P0685 Isuzu 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 Isuzu 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 19,777

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

What does this mean?

What are the Possible Causes of the DTC P0685 Isuzu?

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 Isuzu?

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 Isuzu 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 Isuzu code?

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

Need Help with the Code?

Get the P0685 Isuzu 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 Isuzu Code

1. What are the common symptoms of OBDII code P0685 in an Isuzu vehicle?

- Common symptoms include engine misfires, poor acceleration, stalling, and an illuminated Check Engine Light.

2. What does the OBDII code P0685 Isuzu indicate?

- The code P0685 indicates a problem with the Engine Control Module Power Relay Control Circuit being open.

3. What are the possible causes of the P0685 code in an Isuzu?

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

4. How can I diagnose the cause of the P0685 code in my Isuzu?

- To diagnose the issue, you can use a multimeter to check the continuity of the power relay circuit, inspect the wiring and connectors for any damage, and test the engine control module relay for proper functioning.

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

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

6. How can I repair the Engine Control Module Power Relay Control Circuit Open issue?

- The repair typically involves replacing the faulty engine control module relay, repairing any damaged wiring or connectors, or replacing the engine control module if necessary.

7. Will resetting the OBDII code P0685 clear the issue in my Isuzu?

- Resetting the code may temporarily clear the Check Engine Light, but if the underlying issue causing the code is not addressed, the code is likely to return.

8. Is the P0685 code specific to Isuzu vehicles?

- While the code P0685 is commonly associated with Isuzu vehicles, it can also occur in other makes and models that use OBDII systems.

9. Can a DIY enthusiast fix the P0685 code issue in an Isuzu?

- Depending on your level of experience and access to tools, a DIY enthusiast may be able to diagnose and repair the P0685 code. However, professional help is recommended for complex electrical issues.

10. How can I prevent the recurrence of the P0685 code in my Isuzu?

- Regular maintenance, checking and replacing relays as needed, and addressing any electrical issues promptly can help prevent the recurrence of the P0685 code in your Isuzu.