Need help finding oxygen sensors on 2.7t...I think there is 4.

I'm sure there is a post about already....just cant find it.

Thanks
J

 

There are 4, 2 which control fuel trim, located on the downpipe just after the turbo flange and before the pre-cat, 2 others just after the pre-cats on the downpipes. Rear or lower sensors are easy to change, Front or primary sensors are the ones that are nasty to change. Check the audi diy site in either the B5 S4 or C5 A6 section for O2 sensor removal. Make sure you have lots of skin on your hands, casue your gonna lose some