Is a code P0051, bank 2, sensor 1 considered downstream?

Question

On a 2008 Subaru Tribeca. I just want to make sure I am ordering the right part.

Thanks!

Answer 1

P0051 H02S heater control circuit Bank 2 Sensor 1

This is for the upstream H02S sensor. Your engine design is considered a V-6 So where number 1 cylinder is located this would be considered the first Bank or Bank 1 (Because cylinder 1 is closes to the front of the engine) , the other side where cylinder 2 is this is the 2nd bank or Bank 2. Sensor 1 this is the upstream or the engine management sensor. Sensor 2 this is the downstream or the catalytic monitor sensor.Here all the Sensor 2 are monitoring the catalytic convertor.And all Sensor 1 monitor engine performance