Oxygen sensor location

It is upstream and number 16 in the diagram.

In the diagram it looks like it is the sensor located between the fan and engine. is that correct?
When i went to Autozone they showed the upstream sensor was different then the downstream sensor, but when i go online for the part it shows you can use the same sensor for upstream and downstream.
Is that true? do you know why?

It is screwed into the exhaust manifold that diagram is horrible. Also, the upstream screws in and the down stream sensor bolts in so there is no way they can be the same. Have you tried a website called rock auto dot com for parts? They have good prices and I have bought a ton of parts from them over the years. I also have a five percent discount code for them if your interested.

Hi again Saturntech9..ty .i replied Aug 23, but i don't know why my reply is not here..but here's an update as of now..had to get new battery so nothing done for5 days.

i was told to test the heating element of the bank2sensor1 with a multimeter b4 replacing it to make sure it was no good..

While still on car i tested the2black wires and it read 3.2..as far as i know that means it's good so i left it in?.i had to replace my old battery so CEL was auto reset..now it will idle 4ever, but once i drive 2 blocks the CEL comes on with same code p1150 b2s1 (autozone)..
P1150 Lack Of HO2S-21 Switch Fuel Trim At Limit (2carpros site)

I'm so confused..also once i reconnected the sensor after just testing it, it brought my rpm from1500 (where it always was, i didn't know that wasn't normal) to now it is 700-750..

it puuurs like a kitten n so quiet now..i didn't realize the past 2yrs (since that sensor was installed by shop) it was running like crap i just thought it was how a 17yr old runs..

Can it still be sensor if it reads ok?
Am i testing the wrong sensor?(By radiator)
Can you really even test a sensor?
Can something else make sensor code p1150?
I bought a OBD2 scanner and use the app "torque lite" that checks a "million" things(throttle position manifold, Mass air flow rate, fuel trim short term, Etc) but i don't know exactly what to check or what numbers are good or bad..i only know CEL codes..
Could it be a fuse? If so where?please help..ty..

Honestly i don't think it's my b2s1 because it only has 6000 miles on it unless 3.2 is not good..

All of this started when i dropped a screw in between the battery n air filter compartment that has the MAS on top..,and i was digging my hand in between battery n air filter thing ..which was making the air filter thing move..but I've checked for hoses or anything that could have become disconnected..

Here are the testing procedure and location for the sensor.

Disconnect the A/F sensor connector.
Using an ohmmeter measure the resistance between terminals +B and HT. Resistance: 0.8 - 1.4 Ohms at 20 °C (68 °F) It the resistance is not as specified, replace the sensor.
Torque: 44 Nm (440 kg.cm, 31 ft.lb) Reconnect the A/F sensor connector.

If the sensors tests good you can have a MAF sensor that is slightly off but not enough to cause a code or a misfire can cause this as well, have you installed new spark plugs lately?

Here are a few guides that can help us get the problem fixed.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

and

https://www.2carpros.com/articles/how-to-change-spark-plugs

Please let us know what happens.

Cheers, Ken

The code isn't for the heater circuit it's for the o2 sensor readings number one fix is replacing the sensor.But if it started since you were messing with the air box tubes check for rips recheck for loose connections etc that will set a code.

Sorry ken but i have no clue about cars I'm learning as i go...I have no idea what terminals +B and HT are..can you tell me? Is that sensor wires? If so what colors and what color to connect to on multimeter?

When checking for resistance should the ignition be on or car be started? And what settings on multimeter would i use ?

Also saturntech9 still checking for loose or damaged hoses..
Thank u both so much..

Hi no problem getting people to know car repair is what we do! It is fun most of the time. :) Set the volt meter to OHMS here is a guide to help you see how to work a volt meter

https://www.2carpros.com/articles/how-to-use-a-voltmeter

The terminals you need to test are the two near the three notches on the connector. Check out the diagram above and see how they are holding the connector to the oxygen sensor.

I agree with Saturntech9 that the problem could have nothing to do with the sensor the code is saying the sensor reading is out of range which can be caused by an engine misfire. Have you done a full tune up lately?

Here is a guide to help

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Please let us know what you find.

Cheers, Ken

Or a air leak in the air filter inlet tube or a vacuum leak.

yes it is so much fun.. im learning so much.. but frustrating at the same time.I dont want to make it worse so I've been without my vehicle for 3weeks trying to do it on my own..and i cant pay a shop to play a guessing game at my expense..

oh my i feel so duh...i just found out that +B and HT are on the voltmeter...im laughing at myself right now..i just need to know what color are the correct 2 wires im suppose to test? with ignition switch in on position {vehicle not started} I previously tested the heating element {2black wires} measured 3.2..was told black wires was wrong 2 wires.

FOR NEW TEST
once i know "THE CORRECT" color wires I'm suppose to test,{with igniton switch in on postion} and if not between 0.8 and 1.4 then i should replace sensor..and if within range then its dirty MAFS..

I did buy new air filter, and iridium spark plugs and was going to install once the sensor problem was resolved.. but dont think i can do spark plugs because i hear the back 2 on the rx300 are extremely difficult to get to..

also i keep hearing about dirty MAFS so i bought CRC mafs cleaner but "in the directions" is says not to be used on Lexus vehicles because Lexus has a unique brand MAFS and will be damaged..what brand cleaner do you recommend i use to clean MAFS since i cant use CRC MAFS cleaner?

oh my god i think im going to lose my mind...im WRONG WRONG WRONG...the +B and HT are NOT on the voltmeter...but i cant find what the correct wire color is for +B and HT...i did the 2 black wires 2weeks ago and they were 3.2ohms but was told those were the wrong wires to test because the heating element is not the trouble code im getting..

Im glad you are having fun, I do too it why I got into this field many years ago. Here is the engine wiring diagrams (below) so you can find which wires you are looking for to complete the test.

The wires you want to test are black/white and blue.

Please let us know what you find.

Cheers, Ken

SORRY I don't understand the diagrams...but over the weekend i tested white n blue w/multimeter,it read nothing.. I was so frustrated I went ahead and just replaced air filter, and the bank 2 sensor 1 on my own and turned off the CEL with the OBD2 scanner..so far I have only driven about 40 miles on a full tank on freeway n streets to see if CEL would come back on..it hasnt so far ,,but now when i connect the OBD2 scanner after driving for 15 minutes then have car at IDLE it says..closed loop using 02sensor for fuel mix.

CAN YOU PLEASE PLEASE PLEASE LOOK AT THE INFO AND NUMBERS BELOW AND TELL ME IF YOU SEE ANYTHING BAD OR ANYTHING I NEED TO CHECK, TEST. FIX, OR DO??

engine load- 14.7 throttle position 10.2% MAF 3.2% intake air temp 108f timing advance 15
stft bank2- -0.1% ltft bank2-3.0% stft bank1- 0.1% ltft bank1- -2.3 coolant -194
02s5 wr lambda v- 3.3 02s5 wr lambda ratio- 1. 02s1 wr lambda v- 3.3 02s1 wr lambda ratio- 1.


AFTER SENSOR REPLACED +++ BEFORE SENSOR REPLACED
misfire- complete
fuel system- complete
components-complete
catalyst- complete +++ catalyst- incomplete
heated catalyst- not available evap system- incomplete +++ evap system- complete
secondary air system- not available
A/C refrigerant- not available
o2 sensor-complete +++ 02 sensor - incomplete
02 sensor heater-complete
EGR system- not available

THANK YOU SO MUCH FOR ALL OF YOUR HELP.

also it seems when 1thing goes wrong everything follows suit...
there is a buzzing noise that comes and goes behind component screen heater / A/C / radio..the heater, a/c, everything are "OFF" when it buzzes,..BUT i can also purposely make it buzz by pushing dial to switch the positioning of where i want heat or air to go if it were turned on,..Do you know what that could be??

The last problem seems like something different but it looks like you might have the original problem fixed. Keep driving the car so the computer monitors can run and that should satisfy the remaining operations.

It would be good if you can make a video with your phone of the buzzing noise and upload it here. Should be ready later today.

Cheers, Ken