I read many post on here about the location and codes and what not. I have located the sensor, passenger side after the cat but I cannot find the clip. I've seen in videos that on the es and rx models you have to remove the seat from the car. Do you have to do the same on the is models? If so I'm just going to the dealership.

 

Put the seat all the way back. Pop the door sill up and peel the carpet back. Rite on the underneath of the center console furthest up that were the clip is to unplug it. About five min to do.

 

The above is not 100% necessary. With a little bit of force, grab the end of the carpet on the passenger side nearest the center console and pull back towards the seat. With a little persuasion, you can get it folded over and pulled out from under the center console enough to access the downstream sensor connector that is fastened on the structure of the center console. No tools needed, just your two hands.

This goes for both sides too!