O2, Oxygen Sensor, REAR or Secondary Cylinders 1-4 – PASSENGER SIDE originating pipe (OEM) for Audi D4-D4.5 A8-S8 & C7-C7.5 S6-S7-RS7 w 4.0t

New Factory or Quality brand Audi/VW Part, see product name.

latest revision and replaces 4H0906265B

IMPORTANT NOTE: The factory and some aftermarket downipes criss cross to you need to go with the starting location of the pipe that attaches to the turbo. So this O2 would be physically on the DRIVER side of the vehicle on the PASSENGER side originating pipe on a stock or some aftermarket downpipes.  JHM and some other aftermarket pipes do NOT criss cross the pipes so this O2 would go on the PASSENGER side of the vehicle on the PASSENGER side originating pipe.  If the rear O2s get crossed from bank to bank you can have weird fuel trim and other such codes.