I have an O2 sensor problem in my 92 SC300 and its causing my ck eng. light to come on and gas mileage to drop dramatically. I get code 27 and it says its the sub O2 sensor malfunctioning. Which O2 sensor is the sub O2 sensor? I have only found the 2 on the headers. Are there any others some where else along the exhaust?

 

there are 2 right by the tranny tunnel if i remember correctly. right under the shifter area.

if you look under the cabin area, you can see 1 wire on each side coming from the tranny tunnel.

 

Alright, I climbed in, under, over, around and everywhere I could get to and did not see any O2 sensors in the tranny tunnel. The only 2 sensors I found were on the headers right before the first Cat. I even went so far as to grab the exhaust pipe from the 1st cat. and with my hands around the entire pipe, I slid all the way down the the 2nd cat. and didnt feel 1 single o2 sensor. So i am wondering where the heck is the sub O2 sensor located so I can remove it and get it replaced?

 

I believe you only have the 2 that you found already on your 92 sc300. If it was an sc400 it would be a different story.

 

Ok so if there are only the 2 O2 sensors, which one would be considered the sub O2 sensor? They both only have 1 wire coming out so I am just a little confused. Thanks for the all the info and help.