It's been a while, but I thought I'd wrap this up. I appreciate everyone's suggestions; I discovered what the problem was after I gave up and bought a set of springs and removed the air suspension completely. As I was dismantling everything I discovered that the "air supply control unit" had corroded at the contacts, in spite of their being no water damage in that area at all (which, I'm told, is something you have to watch out for.) Part #13 in the diagram, can get used ones on the eBays for maybe $40. But now I don't have to worry about that system malfunctioning and eating my money ever again, so I'm ok with that. :thumbup:

Thanks for sharing , sad that since money men got more involved in car making the longevity a reliability took side of things took a nose dive

I have the same issues and going to replace with springs.

Highjacking this thread since I'm having somewhat similar problems with my air suspension, and at a loss for what to do next:

2005 e53 4.8iS with the intermittent Inactive Suspension message, which I finally diagnosed to a bad passenger side front sensor (using INPA). Soon after the sensor was replaced, the rear driver side started sagging to the bump stop and the rear passenger side would also drop but not as much. The system resets itself sometimes to normal height all around, and at other times gets stuck and be completely inactive.

What should I be looking for? Does the system need to be reset/recalibrated after a sensor swap? Or is this an entirely new problem?

Same things happened until I replaced the seals in my pump. This also happened when the suspension bits were replaced and the sensor was attached incorrectly.

Passenger side front sensor was replaced and installed properly, that I'm sure about.

Are you then suggesting that it's the compressor? And once again, once a sensor is replaced does the system need to be reset or recalibrated?

See the rear springs for our car, do they use the same springs in any other model? Hoping to get them cheaper.

You should really make a new thread. I have some tips to share, had the same issue and now I'm trouble free after a month of daily driving.

Took your advice and started a new thread: https://xoutpost.com/bmw-sav-forums/...ml#post1176727

I must have a loose wire stopping mine working. Every time I push to clear the message off my dash to view other things the message pops up again right away. Finding that wire ain't going to be fun.