They used to use an OBD scanner to check the readiness, but it's been a while. Basically, when you clear the CEL, it resets the readiness codes. Takes 50 miles or so of driving to get them to adapt.

I'm not a VAG guru, but is there something I'm supposed to do to keep them cleared? They shop relocated the 02s, but I've had this CEL ever since then. I have some small pin holes in the welds where I can see exhaust is getting out, and I tried swapping the sensors around too. Thanks for the insight!

my cel was on but i dont know if it is the programming that flagged a code they couldnt find or what but they still passed me. that was in mid august

<ul><li><a href="http://www.aircarecolorado.com/elements.htm#Visual%20Inspection">http://www.aircarecolorado.com/elements.htm#Visual%20Inspection</a</li></ul>