P0431 code. Replace front or back o2 sensor before the cat?

Question

Where are the front and back O2 sensors located also.

Answer 1

P0431 Warm up catalyst efficiency below threshold Bank 2

The way to find the Bank are to first find Bank 1, from there the other side is Bank 2,  Bank 1 is always where cylinder 1 is located,

​ Here the cylinder where cylinder 1 is located anything on that side is Bank 1, the other side is Bank 2

 Here the over view of the engine where cylinder 4 ,5 ,6 is this is Bank 2, For your code P0431 , the Downstream 02 sensor which is the 02 sensor behind the catalytic convertor these are catalytic monitor sensor all they do is monitor the efficiency of the catalytic convertor, , P0431 is behind the catalytic hopefully it is a fauylty 02 sensor and not a catalytic

Read more :https://www.autocodes.com/p0431.html