Does anybody know which aftermarket cat will not throw codes on a 2000 A6 4.2?

 

One that works LOL! Any cat that is functioning won't throw a fault code. If you have fault codes for your cat converters but engine performance is still good you might need the re-flash from audi. It basically flashes the ECM to make it less sensitive to the rear O2 sensors.

 

everything works and performance is good, but code keeps coming back. Mr. Converter cat.
Where do you get the reflash?