DA8

I've had the yellow light for some time off and on. Would restart the car and it would go off. Over a few months yellow light came on more frequently and would not go off with restarting the car. Now stays on all the time suspension in hard mode, with green light coming on to keep it company sometimes. I ran Vag scan and got 01487-System Function Test 008 -Implausible Signal.

There does not seem to be any leak, no one side or end is lowering significantly. But the main problem seems to be the compressor is not running. I've rebuilt my original compressor 2 times, the last time about a year ago. The measuring blocks on Vag show 6.8Bar pressure in the system and RELAY OFF for compressor status. I have not seen it come on at all during drive test it stays in RELAY OFF status and the pressure only changes slightly around 6-8Bar, but the compressor does not come on at speed or stopped.

So unless I'm missing something I've narrowed it down to something is preventing the compressor from running? I changed the relay last night under the steering wheel left side and checked the "level control' fuse on the right side pillar. This had no effect.

Is there a compressor fuse that is separate from the fuse on the right side pillar for level control? Could my compressor be shot and not running? What would cause it to not run and is there a way to test it?

dvs_dave

So you’ve tried to run the output tests and it won’t let you? What measuring blocks can you read, and do the readings make sense?

DA8

I started it after writing this post and for the first time the compressor ran. The yellow light was not on at first, then the green light was on, then the green light went out, and the yellow light came on.

I have run the measuring blocks, and they seem normal to me. All of the heights are plausible. Nothing is not showing green in the measuring blocks until you get up to about 14 or 15 and then they are red.

The output test don’t seem to work. Which function is that under. I try to do adaptation and it runs through a series of leveling exercises for each corner, but that didn’t really accomplish anything.

​​​​​​​I think the problem still has something to do with the compressor. Even though the compressor did come on, it only came on when there were no lights on. As soon as the yellow light came on no more compressor, so something is preventing the compressor from running, and that something is the actual problem but I don’t know what it is?

dvs_dave

You need to run the output tests in VCDS as a start, to see which tests pass/fail. Output test sequence is started by selecting the option when in the level control module, and then following the prompts to cycle through them all.

quattropowerA8

Puede ser el sensor de temperatura del compresor , que esté roto y no deja arrancar al compresor .

DA8

That was it. 209,000 miles and I finally gave up after 12 years of ownership. The suspension is frustrating, but I know I could have fixed it. The real clincher was that the transmission was thunking on 2nd and 5th gears. After changing the tranny fluid didn't fix it, just replaced the fuel injector connectors, front wheel bearings, and oil leaks in the last year. But the tranny was the killer, I knew it was only a matter of time before I could no longer manually shift it. Auto shift had already failed. So I traded it in to off load it. Got a 2013 BMW M6 with low miles on it for a replacement. The A8 was the best car I ever had so far and I outlasted many members on this forum. But I thank the forum, this forum has been a great community.

dvs_dave

Dumped it huh. Good luck with the M6, you’ll definitely need it. Maintenance ****-shows.