Hello everyone,

Okay, putting this up for reference. Got this information from someone directly from Denso who helped clarify everything.

Denso 234-4261 Oxygen Sensor - Downstream Front - Bank 2, Sensor 2
Denso 234-4064 Oxygen Sensor - Downstream Rear - Bank 1, Sensor 2

Densor 234-9047 Air Fuel Ratio Sensor - Upstream Rear - Bank 1, Sensor 1 ( closest to firewall )
Densor 234-9042 Air Fuel Ratio Sensor - Upstream Front - Bank 2, Sensor 1

 

This gets very confusing because in the Lexus service manual sometimes they call the drivers side* (if you have a LHD car) bank1 but in other places in the manual they say the opposite. I would go with the description for the parts maker, if they have one. This was asked and answered a while back someone posted (sorry can't remember who) the "correct" info meaning how parts suppliers designate banks. Hopefully that person sees this thread.

I'll search and post the info if I find it.

*drivers side if the engine was north/sound in a RWD car, if FWD then left is in fact closest to the radiator. That is how Lexus and Toyota designate banks, except when they don't depending on where in the service manual you are.

 

After a quick search didn't find the post that described where all the sensors are, but parts stores and the like will usually say bank1 is by the firewall. I personally disagree with this but that's another discussion..... so consider firewall bank1.

 

Bank descirption

 

Thanks for this. Though, according to the document, I would have just one Bank 1, and three Bank 2's it looks like, so it doesn't help with the picture reference I have.

 

Thank you fortitude and Lexus2000 . I've updated my original post with the information I was looking for.