My 03 A4 1.8T just threw code P0420, looks like either the catalytic converter or one of the O2 sensors in front of or behind it is bad. The catalytic converter is covered by my 8 year/80,000 mile emissions performance warranty, however according to the dealer, the O2 sensors are not. Any idea how much it costs to have one of the O2 sensors replaced? From what I remember hearing in the past, its not too expensive.

 

my rear one is bad, cost at the dealer for the part alone is $198.. you can get it online for about half that... im sure they will charge two to three hours labor,plus $100+ to clear the code so if the dealer does it, i would say $500 minimum

 

this may be a dumb question, but when the time comes for clearing the codes can he use the obd II scanner at auto zone or advance auto to clear them or wont that do the job?

 

Well, the scanner at Autozone cleared my P0300s earlier. Should work ...

 

yeah you can do that, they usually make u press the button... find someone local with vag to do it

 

Bosch oxygen sensor is about 125 dollars over the net. A local garage can change it and would probably charge 75 dollars labor. It is a simple DIY, except that the sensor is usually frozen in place with rust. After ripping every muscle in my arm, I gave up and had my garage take it out.

 

I think there was a thread like this on one of the other audi forums recently. I believe they figured out that the O2 sensor is covered under the 8/80k warranty. They had to contact AoA to get it taken care of.

Take a look for that thread. it may save you some $$.

 

damn i just rolled over 80k..... mine came out with a little muscle, but nothing crazy hard, just had to get a good angle on it

 

i agree, i too attempted a diy on this but rust stuck the sensor in place so its pretty difficult to force it free without damaging the surrounding parts.