Hello all, I have a 2002 A6 3.0 fwd and need to replace the cats. The dealer said 1600 so im going an alternate route. Can I just buy universal cats and get them welded on with no problems? Is the o2 sensor in the cat itself?

 

From what i know of the sensor is before and/or after the cat - im not sure if you could go the universal route - i have an 02 a6 3.0 awd and have to replace mine soon but with mine theres that flex tube **** before it that allows independent movement so im not sure if you are looking at welding it into that which mine is starting to rust around there so i have this project coming up soon

 

before you change your cats do a 30 minute good fuel inj service to cleean carbon build up did this too mine cat codes went away

 

BG 44K, or seafoam fuel system cleaners may help but I doubt it.

 

I have 2 universal cats installed, not because my oem cats went bad, but because I broke my flex pipes driving through snow banks. There was no place to weld the new flex pipes onto the cats that wasn't either broken or rusted. I have magnaflow brand aftermarket cats, parts and labor to have them installed cost me ~$600.00. It's only been 5 months since getting them installed but I don't expect to have any issues with them.

For the original poster with his 02 FWD A6, I would consider selling the car now to avoid spending money on the cats and the eventual replacement of your CVT transmission.

If by chance your car is less than 10 years old and has less than 80k miles on it, the cats are still under warranty.

 

Some people have luck with universal and other have a bunch of trouble.
I'd call Chris at Force Five in Concord NH -
I'll bet he'll sell you Audi Cats for a lot less than the dealer.