Air loss under the choke of the air suspension on VW Touareg
The front valves of back pressure (gearboxes) rot and start to lose an air. It must be replaced or try to clean. First, air suspension line (tube) is removed, the valve around is cleared of oxides. Then the tube is installed again and checked for leaks. If after cleaning the valve does not break, and the system doesn’t lose air, then all is well. Otherwise, the valve needs to be replaced.
How to change dust cover on VW Toureg air suspension?