I have been watching this site for about 3 months and I have noted the large number of posts related to complaints about the Check Engine Light being activated for many and varied reasons on the A4. Frequently, Audi is made the villian of these pieces, for engineering a system that is so arbitrary and aggravating.<p>During the holidays I found an article in the January '99(vol. 50 no. 5)issue of "Road & Track" magazine titled "Onboard Diagnostic Systems". This article, located on page 132, seems to indicate that most, if not all, of the problems with Check Engine Lights described on this forum can be traced to the Federally-mandated use of the OBD-II computer protocals on all current autos sold in the US.<p>I might suggest that everyone read this article and it might even be considered for inclustion in the FAQ section, to at least help those of us that experience problems with Check Engine Lights understand what is going on and who is actually responsible for this situation.

The big question is: "Who is supplying the engine management controls to Audi?" Some systems are better then others but there are also a lot of other factors too. I'm sure Audi will not tell you who they are using as a supplier. The electronics on the A4 appears to be it's biggest problem.