GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Park Avenue 🢒 Suspension 🢒 Automatic Level Control 🢒 Automatic Level Control System Operation Check

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

Turn the ignition switch to the ON position.

Important: This action may be overridden by the height sensor if a load has been added or removed from the vehicle.

After approximately 35-55 seconds, the air compressor runs for 3-5 seconds.
    • The air compressor cycles on and off frequently. If no air leaks are present, go to the Rear of Vehicle Low .
    • The air compressor runs excessively. Check for a disconnected or damaged air tube or a damaged shock absorber. If OK, go to Rear of Vehicle Low .

2

Add a 300 lb. load to the luggage compartment.

After a 17-27 second delay, the air compressor runs and the rear of the vehicle rises to the correct trim height. Refer to Trim Height .
    • The air compressor cycles on and off frequently. If no air leaks are present, go to the Rear of Vehicle Low .
    • The air compressor runs excessively. Check for a disconnected or damaged air tube or a damaged shock absorber. If OK, go to Rear of Vehicle Low .

3

Turn the ignition switch to the OFF position.

Remove the load from the luggage compartment.

After a 17-27 second delay, a hiss of escaping air may be heard, and the rear of the vehicle lowers to the correct trim height. Refer to Trim Height .

After a 17-27 second delay the rear of the vehicle remains above the correct trim height. Refer to Rear of Vehicle High .

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.