P0685 Fault Code

ECM/PCM Power Relay Control Circuit/Open

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0685 fault code indicates an issue with the ECM (Engine Control Module) or PCM (Powertrain Control Module) power relay control circuit, specifically when there is an open circuit. This can lead to complete failure of the engine management system, affecting the overall performance and functionality of the vehicle.

What are the symptoms of the P0685 code?

Symptoms associated with the P0685 fault code often include:

• Engine not starting or failing to run.
• Unresponsive dashboard lights or warning indicators.
• Reduced engine performance and efficiency.
• Random engine stalling while driving.

What causes the P0685 code?

Possible causes of the P0685 code include:

• A faulty ECM/PCM power relay.
• Broken or shorted wires in the relay control circuit.
• Poor connections between the relay and the ECM/PCM.
• A defective ECM/PCM itself, which may be unable to provide the necessary ground signal to operate the relay.

How to fix P0685?

To resolve the P0685 error code, consider the following steps:

• Inspect the ECM/PCM power relay and replace if found defective.
• Check the wiring and connectors in the control circuit for signs of damage or corrosion and repair as necessary.
• Test the ECM/PCM to ensure it is functioning properly; replace it if it is defective.
• Clear the error code and perform a test drive to ensure the issue is resolved.