2003 4runner V6 w/ P0031 code

[mikebedis]

Check enine light and VSC lights both came on. Scanner reads a P0031 code which is bank 1/ sensor 1 O2 sensor. I understand this is sensor upstream of the cat but which side? Driver's or pass? Suggest just going forward to change sensor ?

 

[Stuck CAPS]

Check enine light and VSC lights both came on. Scanner reads a P0031 code which is bank 1/ sensor 1 O2 sensor. I understand this is sensor upstream of the cat but which side? Driver's or pass? Suggest just going forward to change sensor ?

I'd say just replace both, because it seems that, with me at least, when one part goes out, the other goes out near instantly.

 

[BOSMECH]

Passanger side is bank 1
If you go to the Service manual it shows a good picture of all the sensors on page 05-25 I just cant transfer a PDF file here or just don't know how but when you open the service manual up go to diagnostics, then to SFI system (1GR-FE), then go to parloc40 down at the bottom. That has the best picture ever.