2003 E500 air suspension clicking
 

My 03 E500 has 4 corner airmatic suspension. The car never sags, even when it's parked for days without driving so I'm pretty sure I don't have a leak in any of the bags. The car will raise and lower when I click the button. I can also feel the change in the ride between the sport settings and the comfort and the comfort with the vehicle raised and it rides amazing. Periodically the air ride malfunction light will come on, but everything seems to still operate fine. I also hear a clicking noise at all 4 corners of the car sometimes. Has anyone had any symptoms like this at some point so I know where to start trouble shooting?