Hi everyone,
I just purchased a 2001 Audi A6 2.8L v6 few weeks ago. This morning the check engine light came on. I took it to Autozone to scan it and this is what came up:

Trouble shooting PO420
Catalyst efficiency Low-bank 1
Explanation: The oxygen sensors monitor the catalytic converters
ability to store oxygen.
The PCM has determined that the catalyst system efficiency for bank 1
is below the threshold for the current operating conditions. (Bank 1
identifies the location of cylinder #1 while bank 2 identifies the
cylinder on the opposite bank)
Probable causes:
1) Catalytic converter defective (possibly due to #2, #3, or #4)
2) Engine misfire or running condition
3) Large Vacuum leak
4) Engine oil leakage into exhaust-valve guide seals, piston rings

Somebody told me that there is a wayI canbypass the sensor so the check engine light can stay off...if there is a way, does anyone know how I can do it?
Thanks

 

I recommend just erasing the fault. If it comes back a 2nd time then the Cat needs to be replaced.