awdinut

clearing code out only keeps CEL off for a few days so I guess I will have to get the problem resolved. Is there a common failure as far as the component is concerned ?

MP4.2+6.0

it was connected to vacuum hose leaks--the small (+/- 3mm) stuff. Would often feel a little motor shaking when cold too. IIRC, that system also takes two motor warm up cycles to throw the CEL, and the CEL also turns off if the system later reports ok. Hence why you wouldn't see the light come on right after clearing codes, even if problem remained the whole time.

awdinut

The vacuum hose material on the D3 A8 4.2s is not the same as what they used on the D2/A6 4.2 . The newer stuff does not shrink away from the connectors and cause a vacuum leak. So there is something else going on. Used to be every now and then but now as soon as the neccessary number of drive-cycles take place the CEL comes back on.

The Simps

I have had the same issue for months. Had pump checked, lines checked up to the inlet. Now need to strip a lot of the inlet out to check the remaining hoses but I suspect its one of the control solenoids.