P0687 Fault Code

ECM/PCM Power Relay Control Circuit High

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

The P0687 fault code indicates an issue with the ECM (Engine Control Module) or PCM (Powertrain Control Module) power relay control circuit being detected at a high voltage level. This can disrupt the operation of the control modules, potentially leading to poor engine performance or failure to start.

What are the symptoms of the P0687 code?

Symptoms that may accompany the P0687 fault code can include:

• Engine won't start or cranks without starting.
• Check Engine Light illuminated on the dashboard.
• Inconsistent engine performance or stalling.
• Electrical issues with power accessories or components.

What causes the P0687 code?

Common causes of the P0687 fault code include:

• Faulty power relay or its circuitry.
• Short circuits in wiring leading to the relay.
• Defective ECM/PCM.
• Poor electrical connections or corroded terminals.
• Issues with the battery or charging system affecting voltage levels.

How to fix P0687?

To resolve the P0687 fault code, consider these steps:

• Inspect and test the power relay; replace if faulty.
• Check the wiring and connectors associated with the relay for damage, corrosion, or shorts.
• Test the ECM/PCM for functionality; reprogram or replace if necessary.
• Verify the battery and charging system are in good condition, providing correct voltage levels.