Can someone tell me which side of my 2009 gs350 would the downstream O2 sensor be with a PO420 code?

 

Bank 1 is passenger side Bank 2 is driver side, P0420 is Bank 1.



Make sure it's actually the sensor at fault though.
CONDITIONING FOR SENSOR TESTING

 

Thank you Skur. The reason I asked is I have seen info that says Driver's side and other info saying it's the passenger side. I appreciate all the info you sent

 

Recently got this code as well. Had VSC, check engine light etc. Mechanic replaced exhaust flanges since they were burnt and everything was fixed. Also thought that problem was with O2 sensor but nope. Exhaust is all original.

 

Thanks, Have been reading posts that mention exhaust problems such as pinholes, will have flanges looked at also