Check engine light came on in my 2002 A6 3.0 took it to Auto Zone and got the following code...

P0421

Anyone know where my problem is and how to fix?

 

From the Bentley:

2 hits for the 3.0-

P0421
16805
Primary catalytic converter, Bank 1 Too inefficient
- Replace catalytic converter


P0421
Warm Up Catalyst Efficiency Below Threshold Bank 1

- Check Oxygen Sensor (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC) Page 24-124
- Check Oxygen Sensor (O2S) and oxygen sensor control behind Three Way Catalytic Converter (TWC) Page 24-135
- Check catalytic conversion Page ST-43

Sounds like an O2 sensor or catalytic converter problem.

Do a search for the code on AudiWorld. I found this -


http://forums.audiworld.com/a6/msgs/623856.phtml

 

Ok, I went back to Auto Zone and they gave me the printout for the code.

It says...

"The PCM has determined that the warm up Catalyst efficiency for bank 1 is below threshold for the current engine operating conditions. (bank 1 identifies the location of cylinder #1, while bank 2 Identifies the cylinders on the opposite bank)

So I'm figuring it's the O2 sensor and I will attempt to replace. has anyone here ever replaced them and does anyone know which side this is? before or after the converter? I read through some of the searches and there is a lot of debate on what side is what.

Any DYI info out there?

 

I just thought of something, so maybe someone can help with information.

Is the O2 sensor and Converter part of the emissions warranty? And if so aren't the emissions warranties longer than the standard warrant?

The car is a 2002 model and has 55,000 miles on it

Is Audi responisble for fixing it?

 

Cat yes, O2 no The cat has a 8 year 80000 mile fed. warranty