I bought an '01 A4 1.8Tqt a couple weeks ago, and after driving it for about a week the CEL came on. I peeked under the hood and noticed a pile of shop rags (seriously, there were like four or five of them) underneath the oil filter. I pulled these out and the next day the CEL went away. Then, last week, it came on again. A couple days after that, I got a BRAKE LIGHT error on the DIC. So today I checked my driver's side brake light and the bulb was broken. Replaced it, but I still had the BRAKE LIGHT error. However, the CEL was off. Replaced the other brake light, and now I have no errors and no CEL.

Could the broken bulb have somehow triggered the CEL? I don't have a VAG-COM (yet), so I don't know what code it was throwing, but does this sound possible? Or is there any infamous condition that B5s get that causes this? Maybe something with a cracked vacuum line or a partially-plugged gas tank vent or something?

 

A brake light bulb being out wouldnt throw the cel, thats why the other warning is there. As for why the CEL was coming on, theres no way to tell without codes. Get it scanned at one of the autoparts stores around you and post back with the codes. Also do me a favor and post or link me to some pics of your 944. Thanks.