when i shut the car off and then back on, it lets me change the suspension. and it goes up and down with no problem. but after i drive it for a little bit, the light comes on and then all suspension options are gone except for the one i am currently on.
so we plugged in the vagcom and it had a few red codes. but they had nothing to do with the suspension. there were no codes for suspension. he tweaked around with it for a little, lowered it about a half an inch while we were at it, and i drove about 100 miles since then and the problem hasn't happened again. i parked up at home, put it in standard, lifted perfectly fine. put it in lift, perfectly fine. put it back to dynamic, everything was good. ill be driving the car later tonight again, i hope the light doesn't come back on. but for now, its all good. doesn't even seem like its a relay or a leak. maybe it was just a malfunction?
as i said before, the car is perfectly level. i don't hear the compressor running, it is in limp mode, and it rides rough. any idea if it could be anything else other than that sensor? doesn't seem to be a leak since the compressor doesn't really run and the car is still perfectly leveled.
When I got my A8 it had a recurring 01772 G291 fault on the suspension. My local VAG specialist took a look over the suspension for me and found three issues which are now resolved.
1) One of the four level sensors had water ingress into the electrical connection which confused the suspension when it was driven on wet roads. He fixed this by cleaning up all the contacts, and used a non conductive grease before reassembling.
2) The car thought that all four corners were at different ride heights, so he recalibrated all four corners.
3) The compressor was only outputting 6 bar of pressure, this meant that although the car would raise and lower it did take forever for the front end to lift up. He fixed this by dismantling the compressor and fitting a repair kit which is readily available. The car now rises and lower perfectly, with the front raising smoothly and instantly after the rear has gone up.
Ultimately my 01772 was cured by rebuilding the compressor, the rest of the system was fine including the valve block.