Kev 3.0

I just went to autozone and said i had a p0421 error on my car. The guy said is is from a catalyst warm-up efficiency below threshold. I just had my catalytic converter changed a month ago, so i think its the O2 sensor, which is supposedly not covered under the emissions warranty from the federal government. I was wondering if anyone know what the repair is gonna cost and how much the part is going to be. If anyone also knows where i can find the part for cheap it would be appreciated.

Bronze

His code definition is correct. P0xx codes are OBD-II standard. Also, oxygen sensors are absoultely part of the emissions hardware and should be covered under warranty. However, if the O2 sensors were bad, I would think you'd get a P01xx code, not a P04xx. Do some searching of the archives for this code, and see what you can find. Codes are across vehicle, so don't feel confined to search the B6 A4 forum. The B5 forum archive may have better info.

Depending on your mileage, this fault should be covered under OBD-II warranty, which I thought was 70k or 80k miles.

akula-ssh

I don't recall which parts are covered, but IIRC my dealer said only the parts that're part of the warning subsystem about emission failure is covered. (I know for sure O2 sensors were not covered when a couple failed on my parents' '01 Allroad)

Bronze

Wow. In the US, they are covered, IMHO.

Kev 3.0

I have 59,000 mi on my car does that make a diff? Is there a place to prove to my dealer that the O2 sensor is covered.

A4SnowBoard

My 02' 3.0 had this code come up about a month ago. I got the code cleared and this week it came up again. I checked on some prices for the O2 sensors and the guy from http://www.sjmauto.com told me: "You may want to try replacing the pre cat O2 sensors first, and then run the vehicle and recheck for any stored codes to see if you really need to replace the post cat O2's"
The pre catalytic O2 sensors are $111.79 each, left or right.
Hope this helps.

auditech8309

code for catalyst warm-up efficiency is usually the catalyst. did the dealer replace both banks?

Bronze

Check the owner's manual.

Kev 3.0

not sure he just told me the catlytic converter was replaced.