Bought my 2006 4.8iS in August with 83,000 miles. At about 86,000 started getting the suspension inactive warning. All 4 corners held their height positions and the ride never felt any different.
Took it to an Indy who scanned and found code 74 accumulator pressure remains constant. Clear the code and it just comes back a little bit later.
Took it to a BMW dealer and they just deactivated the system. No longer had the green LED in the height adjustment switch, but still had the annoying error light in the dash.
After reading all I could about the system and people's problems, I had the Indy clean and lubricate all 4 height sensors. Error light stayed off for about a week, and during that time I could raise and lower the height. Error light came back and I have just left it for a couple months until I found a thread mentioning BagpipingAndy.com and his repair kit. For $35 I gave it a try. I rebuilt the compressor in about an hour and then took it to my Indy to clear the code. Still too early to tell if the system is fixed, but I can say this. The height adjustments are much faster than they ever have been since I've owned the car. Fingers crossed it's fixed!
Sent from my iPhone using Tapatalk