Bank 0 Sensor 1 Error on Rav4 2006 2.4

[jonko_p]

Hello, I'm new in this forum, tried to find something on that matter, but didn't.

I have (Bank 0 Sensor 1) error on my Rav4, 2.4, 2006.
The mechanics told me this is the oxygen sensor, but when I read threads in this forum there are several oxygen sensors in a car.
Also I have Toyota EPC and found just 1 part number for oxygen sensor - 89465-42170.
When I look for oxygen sensors on the web, there are 2 Denso oxygen sensors for my car: 234-9044 and 234-4622.
On the Bosch site there are also 2 sensors - one After Catalyst Check and one before Catalyst Check.(part numbers match exactly the 2 models Denso oxygen sensors).

So my question is - are there 2 oxygen sensors working simultaneously in the car and which one is Bank 0 Sensor 1 and why on Toyota EPC is just one part number?

Thank you in advance!

[bepperb]

You have two 02 sensors. One is before the cat, and considerably more expensive.

You may have only found one in Toyota documentation because the upstream one is referred as an A/F sensor in some docs.

Is this under emissions warranty? It should be, depending on mileage and where you live.

[jonko_p]

Thank you for your reply,
Yes there are 2 sensors - one is called Air fuel sensor and it is before the catalyst, the other oxygen - after. I have the OE numbers of both of them and the related Bosch and Denso numbers.

But which one is Bank 0 Sensor 1?
and yes you are right the first one is a lot more expensive.