air suspension warning lights comes on after the first start.

The car sits evenly even when parked for a while (a week or more) and no noticeable change in heights. The lights comes on when driving after this long period of unuse but turns off after a few re-starts. I did notice that the car don't hiss and lower or goes up after I park. How do I check to make sure the air suspension /auto leveling function still works?