rmccomiskie

97 A6. I have a CEL for bank 2 sensor 2. So, I think that's the sensor after the cat but I don't know if it's driver or passenger side.

EDIGREG

Bank 2 is driver's side, cylinders 4,5,6.

Fair Cape-Cape Town

Bank 1 is on the right if you are sitting in the drivers seat. Same side as the air filter.

rmccomiskie

...Not too much trouble although it's a pain to have to remove the crossmember to get at the wires. It really helps to have access to a lift. Had to heat the bung with a torch before I could turn the sensor. Left cat matrix looked good at 177K miles.

Thanks all for the bank info.