Update on my problem.
Problem: Rear left side of the air suspension keeps deflating.
What I have done so far:
-Air bag replaced with an aftermarket (http://www.air-suspension-shop.com/A...rear-4F0616001
-Dealer searched for leakage. None found.
-Replaced air valve unit with an aftermarket one (http://www.air-suspension-shop.com/A...unit-4F0616013
-Read error code: 02646 plausibility level control
But I still have the same problem. I am totally stumped and would really appreciate any suggestions or ideas..
On the side note I had some trouble trying to locate the air compressor and air valve unit so I want to share it here.
Both the air compressor and the valve unit are located on the far right side behind the bumper. I decided to remove the bumper to have better access but you might get away with just removing the cover behind the wheel.
Removing is easy, just the two screws in the front and the power connector. The replacement can only fit one way so you can use the color codes. Just be careful and keep it clean.