BMW
BMW Repair Questions? Ask a Mechanic for Answers ASAP
Hi..there..
Could be several things to cause that issue..obviously the first thing to be checking is for air leaks, normally the airbags or the supply line connections are quite prone to small leaks..ceetainly where the airbags are concerned around the base where it creases can cause cracks in the rubber bellows and cause small leaks which cause the car to drop overan extended period of time.. easy method to confirm that is to get a spray botttle - some soap and water mix and generally spray in the areas around the circuit/ air bags and look for any tiny bubbles of course the system needs to be charged with air before hand... other than that the other usual culprit could be faulty solenoid valve this valve in between the airbag and the main pump circuit behind the rear bumper..so again that needs to be checked out..if the pump itself is actually charging the airbags up and holds then the pump can be ruled out for now
Thats why i mention the control solinoid valves they are quite common for failing internally allowing the suspension to drop..but as precaution inspection wise you have to do the basic checks first like inspecting the airbags and the line connections..with soap/water trick...its not a hard task to carry out..so any good garage should be able to do this for you..as ideally it needs to be on a 4 poster ramp lift "not a 2 post with the wheels hanging" with the suspension fully charged to do a proper inspection..