2001 Audi Allroad Quattro Active Suspension Air Spring Control Solenoid Replacement Cost

Vehicles with air ride suspension use air bags, or air springs, instead of metal coil springs. These allow for variable ride height, automatic leveling, and a very comfortable ride. The drawback is that there must be a system to maintain the amount of air going in and out of the system, and the controller for this system is the air spring control solenoid.

There are two different types of air spring control solenoids. The unit may have solenoids for each airbag installed in one location, or the control solenoids may be located at each wheel. Though these components are located in different positions, they still operate the same way. Either the air bag control solenoids respond to input from the ride height sensors or air pressure sensors by opening valves to let air pressure into the air bag, or relieve pressure from the air bag. This will change the ride height, level the vehicle automatically, make the suspension more or less firm, and stabilize the vehicle.

When the airbag control solenoid fails, the vehicle may not level properly, the vehicle may ride too high or too low, the ride may become unstable, and the driver will be prompted for service by a warning light specific to the manufacturer of the vehicle. Also, vehicles with driver adjustable active suspension systems will notice they are unable to adjust the suspension, or adjusting the suspension does not result in the desired end state.

This issue should be repaired immediately, even in cases where the vehicle simply fails to adjust. Driving with a faulty air bag control solenoid can cause severe instability, quick and unexpected changes to the vehicle's ride height at any wheel, and damage to one or more of the air springs.