O2 Sensor Question

[Sayre]

Anyone have a diagram or a good explanation of which O2 Sensor Bank 1 Sensor 1 is? I know there are four of them but this particular one crapped out. Thanks!

 

[shineydave]

might help if you tell us what car this is on

 

[Sayre]

my apologies.... its a 2000 S4

 

[shineydave]

my 2001 S4 only has 2 sensors, standing at the front of the car looking back bank 1 is the left hand side, bank 2 the right. as you're stateside i'd guess that sensor 2 is the one after the cat since we only got the second sensor in the very last S4's. as standard we only got sensor 1 which is in front of the cat in the downpipes.

so to answer your question sensor 1 bank 1 is the passenger side front sensor