Hello, I have a 2001 A6 4.2L. The car runs perfectly fine, however the check engine light is always on untill i erace the codes, but even then the light comes back on in only a few days. The codes have to do with the catalytic converters, both of them. However it doesnt seem like i need to change them any time soon. So if anyone could please tell me if there is a way of getting the check engine light to stop from coming back on? thank you!

 

Rig the oxygen sensors after the cat to read a constant .75 volts.

 

Yeah actually i read about that somewhere, do u have a detailed instruction anywhere on how its actually done? or maybe an article or something. Thanks for the help!

 

You should take it in to have the cat looked at. I have the exact same car and model and mine is at Audi right now to have the cat and mass flow sensor replaced. They are both covered by warranty and you won't have to pay a thing. I bet it's your CAT.

 

ye, just have to put your feet down at the dealer.
and if they refuse then follow the thing on my website. if you put a constabt .75V then the CEL will still pop up. the voltage needes to vary between .1 to .8 to make sure that the CEL wont pup out again.

 

Where would i be able to find the guide on ur site? and about the warranty, the car isnt under warranty anymore, so how would those components still be under it? and if they are would they be willing to change the cats for free?

 

Some emissions componants are warrantied after the initial vehicle waranty. The cat is probably one of those. The ecm doesnt look to see that the o2 after the cats is cycling only that it is reading. If everything is working ok with the o2 and the cat it should read around .75. There is a slight possiblity that you will get an 02 no activity code if rigged that way but usually only a steady .450v will throw that code.

 

The CATs are covered under a federal warranty until 77,000 miles along with the Mass Air Flow Sensor. I have an extended warranty but didn't have to pay my deductible because of the federal warranty. How many miles do you have on your car? I'm sure your CATs are covered. I can't wait to get my baby back. It has been at the stealership since Saturday morning. I get her back tomorrow!!!!