02 sensor location and description, upstream, downstream, bank 1, bank 2 narrow ban or wide ban?

Hi,

They aren't the same. I have attached the OEM part numbers below for you. There should be a total of three on the vehicle. Two upstream are mounted to the exhaust manifold, and there is one downstream from them. Also, the directions for replacement are included.

Take a look at the pics and let me know if that helps or if you have other questions.

Take care,

Joe

See pics below.

There are 4 1 in each exhaust cat/manifold and 2 in the y pipe that goes to the rear cat/resinator pipe 1 on each side mating to the front bank and 1 for the rear bank most information i have found says front/banks/manifolds is the upstream side and the 2 in the y pipe are down stream but parts houses say different and some say all 4 are the same i have all factory lexus repair manuals the 3 book set wit all the wiring and test values along with the chiltons and motors manuals alond with all factory included lit that comes in the glove box cheap sensors are unreliable and factory sensors are break the bank expensive so i am doing all that is required to get the right sensors in the right spot i am replacing all 4 thank you

That should have two upper wide band sensors and the lowers are "standard" O2 sensors. The normal thing for Toyota and Lexus is to call them an air fuel ratio sensor when they are the wideband versions and heated oxygen sensors when they are the common ones. The problem is that many parts places just call them all O2 sensors. All 4 positions use different sensor part numbers. However like many imports they might be the same sensor but with a different color connector or different length harness which gives them a different part number, even though the part is the same and the changes really don't matter. I've used NTK on Lexus before and they reported correctly, avoid the really off brands though, Like many imports Toyota-Lexus can be very finnicky when it comes to parts. I prefer OE if at all possible.
Bank one is the rear bank on that car, So the way they are listed in the parts is a mess. The Front upper is B2 S1, The Rear upper is B1 S1 (both wide band air fuel), Center is B2 S2 and the Lower is B1 S2 (both standard O2 sensors)

Thank you for all your trouble. Stay well and God bless.

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