Wish you good luck! Judging from the threads here dealers have not been all that successfull at resolving issues around the air suspension.

What stumps me is that the system pops up with "Airsusp. Inactive" on my 4.4 (rear only) from time to time but nothing is wrong and I ignore it.

On 4.8 the pump was clearly not running and the LF was low by an inch, causing real scary problems under braking and the system is completely silent..... There seems to be no pressure sensor in the system which is odd as loss of pressure could cause severe handling problems. I just don't understand the logic of how it behaves.

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2003 4.4i black ext./black int./black headliner (kid's runabout)
2014 535d X-drive, M package, silver/black interior

Sold but not forgotten:
2009 E70 35d, black ext./black int./black headliner (sold 2021)
2006 4.8iS Le Mans blue/cream int./black headliner, SOLD in 2012 sadly...

Other hardware:
2015 Cayenne S (wife's new DD and definitely wroooommmmm)
2016 Tundra 1794 edition crew cab, luxo hauler
2005 Tundra crew cab, weekend hauler. Sold after 150k very happy miles.