EG9 K20A3 4/11/2012Sounds like the seals may have failed in the air shocks themselves. I also think you may have a bleeder valve problem. Follow the lines back and check the bleeder valve to see if it is leaking when you have someone else turn the vehicle on.
The rear height sensor will turn the air suspension on if it see's the suspension is too low. One of the rear air springs is probably dry rotted and cracked, leaking air.You can spray soapy water onto the rear air springs to check for a leak.Other air leak area is under the brake master cylinder ht air line disintergrates.Check for air leaks.Once it gets to the desired height it should shut down. A diagnostic check for codes with a scan tool made need to be done to check system operation and integrity.