does anyone know which part # is the downstream O2 sensor on 2001 20th? if you look at all the O2 sensors they dont make sense, all 3 appear to be before rear exhaust enters pipe. i thought downstream was supposed to be behind the cat.

 

there are no o2 sensors behind the main cat on a 01 on any trim level because its cali spec. the downstream o2 sensors are monitoring the precats. do you know if the o2 you are looking for is bank 1 or 2?

 

neither, i have 3 O2 sensors. bank 1, bank 2, and downstream. at least this is how it looks. the code states "downstream O2 sensor high voltage" & "downstream O2 sensor slow response"

 

all 2k1 are cali spec and have 4 o2 sensors. two are upstream and two are downstream. none are after the cat unless they have been relocated. check out this link -http://maxima.theowensfamily.com/tsb/NTB02-051a.pdf
that is a tsb for both secondary (downstream) o2 sensors.