I replaced the original CATS with after market CATS which I purchased on eBay. CAN Muffler was the seller from Ontario. I had the CATS installed by an Audi Tech who does some work on the side. Everything was fine for about 6 weeks when my check engine light came on. I pulled a code and it indicated I needed a bank 2 driver side O2 sensor. I had a new Bosch O2 sensor installed but still have the check engine light on. New code indicated driver CAT intermittent and passenger CAT static. I am not convinced the CATS are bad. Anyone have any thoughts? I would like to get the check engine light to go out.

 

This is a typical issue with our cars. Really sensitive when it comes to catalytic converter threshold... Anyways here are a couple of things which may address your issue.

1) You have four o2 sensors. You probably meant to say Bank 2 Sensor 2, meaning driver side rear sensor. Anyways, at that mileage, if one of them went bad, then the others are following. O2 sensors are designed to work for about 100K and the rest are probably on their way out. If the rear sensor is picking up proper readings, and the front sensor is being lazy, then you may get a converter related code.

2) There was an ECU update for ATQs for catalytic converter threshold setting. Supposedly the setting on the ECU was too low from the factory. Updated software raises the threshold. Unfortunately it is a dealer the stealer only procedure. I had mine done for the same issue, and it hasn't come back in the past 2 years. I paid about $300.

Either one of the 2 will probably solve your issue. Option 2 is the cheaper of the 2 options to start with, but I suspect you would need to deal with your o2 sensors soon anyways.

 

Thanks. That is great information which I will pursue

 

I just learned that my 2.8 is not an ATQ and I do not think an update exists.