I received a H02S Heater control circuit low Bank 1 Sensor 1. I'm assuming this is an oxygen sensor problem. Correct me if I am wrong. Where do I find Bank 1 Sensor 1? A picture would be great or description.

 

Welcome to CL. This may help. Searching would show that this has been asked before: https://www.clublexus.com/forums/rx-...numbering.html

 

hmm... 6 year old Lexus already having sensor problems. These days it is all about cost cutting, no more quality cars... sad.

 

Do you have access to a scan gauge or similar? Look at your fuel trims and the O2 sensor voltage pattern. This can assist in determining if it's a sensor issue or wiring etc.

 

Clutchless: Thanks for your reply. I've seen this link you attached before but I dont think it relates to the 2010 rx 350 AWD. (Correct me if i am wrong)
i've asked the lexus dealer about the location of B1 S1 and they said it was in the engine bay on the back side of the engine attached to the rear exhaust manifold. (The only exhaust manifold i see is in the front of the engine close to the bumper not the windshield, so i dont know if they are trying to mislead me)

I asked Napa auto parts and they said B1 S1 is on the driver side before the catalytic convertor.
A Garage mechanic said B1 S1 is on the passenger side before the 3 way convertor.
...Solution:.....
I know that there is 2 sensors before the catalytic converter and 2 after. from reading a lot from websites in some cars they mention bank 1 to be after the cat convertor and some before the cat converter. that is why i cant figure this out.

I'll mention a few more things that I think are the cause of this: I was using 87 octane gas more than 91 octane, and i did top it off once
I got the AWD check system, Engine light, trac off lights all on. Car runs fine although i think it might be burning fuel more than the usual.
I received a P0031 saying that a H02S Heater control circuit low Bank 1 Sensor 1 is faulty. That is where the assumption came from that it is a O2 sensor.
I'm hoping it is not the charcoal canister (if it even has one) or any other thing expensive.

The other thing that Im having difficulty in is choosing the correct part number for the Denso O2 sensor. I dont know if it is an upstream or downstream. (i have a feeling its upstream) but also which one right or left. how does Denso define left and right (driver side or passenger side would be better)

afpj: No i dont have a scan gauge just a OBD 2 device Roadi NGS100. i will be using a volt meter and i will light up one end of the O2 sensor to see if i get a volt reading. hope this works ...

 

Here is what an experienced used said in the ES forum and should apply to ur engine also:

"Bank" is which cylinder bank of the V it controls, identified by starting w/either #1 or #2 cylinder from the front. Bank "1" on a Toyota is the R side of the engine, or along the firewall in your transverse application.
"Sensor #" is order from exhaust heading downstream. #1 is before the catalytic converter, #2 after.

So yours should be behind the engine (firewall side) and before the catalytic converter.

Also, look at this video for B1S1 on an rx