Hi Alex ... Here's a link to what Consumer Guides has to say on the matter ...http://consumerguideauto.howstuffworks.com/1992-to-1997-audi-100-s4-a6-s6-2.htm ... Hope that helps. Good luck with your new car!

The "check engine" light comes on for several reasons.  Hopefully the link LouB sent you will be helpful.   The "check engine" light flickered on my 1994 Audi with similar milage to yours.  I was told that the oxygen sensor needed to be replaced.  Good luck.