C0604: Active Air Dam Control Circuit Performance

What it means

The control module monitors the active air dam actuator’s operation. It sets this code when the actuator does not perform as expected in response to a command.

At a glance

• Usually lights the ABS or stability-control warning light

How it works

The active air dam actuator positions the air dam in response to commands from the control module. C0604 sets when the module detects that the dam does not move or respond as expected, even though it has requested a change.

Common causes

Most likely first.

1. Actuator binding or mechanical damage
2. Obstructed air dam
3. Damaged wiring or poor connection
4. Actuator or control module fault

Symptoms

• Active air dam warning light may be on
• Active air dam may remain in its current position

How to diagnose it

1. Record freeze-frame data and use live data to compare the commanded air dam position with the reported position or movement.
2. With the vehicle safely parked, inspect the air dam for debris, impact damage, or anything physically blocking its travel.
3. Check whether the air dam or actuator linkage binds when inspected according to the vehicle's service procedure.
4. Inspect the actuator connector and wiring for damage, loose terminals, corrosion, or poor routing.
5. Test the actuator control circuit and actuator response using the manufacturer's procedure before considering a module fault.

Common fixes

• Remove debris or another obstruction from the air dam's path.
• Repair damaged wiring or clean and secure a poor connector.
• Repair or replace a binding or damaged air dam linkage.
• Replace a failed actuator after confirming its circuit and mechanical load are sound.
• Repair or replace the control module only if testing confirms it is not commanding the system correctly.

Can I keep driving?

A stuck air dam usually does not prevent basic driving, but its airflow function may be unavailable. Avoid driving if it is hanging loose or could detach, and arrange repair.