Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the part of the car that helps control air flow to make the car more efficient. It's like a flap that opens and closes, and right now it's not working right.
The C0604 code is triggered when the vehicle's computer detects a problem with the active air dam control circuit, which is responsible for adjusting the position of the air dam to optimize aerodynamics.
The active air dam is a component that adjusts its position based on vehicle speed and other parameters to improve aerodynamic efficiency. The control circuit for this system monitors and adjusts the air dam's position. A performance issue in this circuit indicates that the system is not operating as expected, which could be due to electrical or mechanical faults.
• Reduced fuel efficiency
• Check engine light on
• Unusual noises from the front of the vehicle
• Faulty active air dam actuator
• Wiring issues in the control circuit
• Faulty control module
Active Air Dam: A component that adjusts to improve aerodynamics.
Actuator: A device that moves or controls a mechanism or system.
• Inspect the active air dam for physical damage.
• Check the wiring and connectors for signs of damage or corrosion.
• Test the actuator and control module for proper operation.
• Replace the faulty air dam actuator.
• Repair or replace damaged wiring or connectors.
• Replace the control module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Regularly inspect the air dam for damage.
• Keep the vehicle's electrical system in good condition.
• Avoid driving over debris that could damage the air dam.
Control System Issue
• Have the vehicle inspected by a professional if you notice decreased fuel efficiency.
• Do not ignore the check engine light.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code has become more common with the introduction of active aerodynamic components in modern vehicles.
Moderate – While not immediately dangerous, it can affect fuel efficiency and should be addressed soon.
Driving with a malfunctioning air dam may not be illegal, but it can reduce vehicle efficiency and increase emissions.
• Vehicle at operating temperature
• Vehicle speed above 30 mph
The active air dam is located at the front lower section of the vehicle, typically under the bumper.
Q: Can I drive with a C0604 code?
A: Yes, but it's best to get it fixed soon to avoid reduced fuel efficiency.
Q: How does an active air dam improve efficiency?
A: It reduces aerodynamic drag by adjusting its position based on speed, improving fuel economy.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
Useful when wheel, hub, or suspension hardware needs correct reassembly torque.
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Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
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