My CEL light just came on recently at 89K miles, P0037 which from what i read online is "P0037 Lexus - Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 2".

I think this pretty much means to replace that O2 sensor, right?

I know on the 2GR engines Bank 1 means cylinders 1,3,5 which face the firewall and pretty much everything back there is a pain to get to. has anyone attempted to replace the O2 sensors back there as a DIY? Is this one of those times to just suck it up and take it to a dealer or third party mechanic?

UPDATE WITH DIY INSTRUCTIONS for bank 1 sensor 2 O2 Sensor:

Did this in an hour. I did NOT need to jack the car up. i slid right in from under the drivers side door and had plenty of clearance to work with.
the new O2 sensor was a drop in replacement, exact same wire length and with all of the clips in the exact spots they needed to be. Everything clipped right in. This is the best part, unlike the sienna, highlander and rav 4 DIY's i've seen for this sensor, you don't have to do anything inside the car to wire up the sensor. no need to remove panels, seats, carpets or anything! everything is plug and play beneath!!

I bought this replacement part, DENSO 2344509 (234-4509).
Also got the Oxygen Sensor Socket, LISLE 12390.




Breaker Bar, O2 Sensor Removal socket, ratcheting socket wrench, pliers, flat head screw driver, PB blaster, safety glasses and flash light. Also pictured is the old O2 sensor and the packet of thread grease included with the new O2 sensor





Close up of the o2 sensor removal tool.





1. Using a flathead, stick flathead into bottom of harness and pull back the cabling that's attached to car.
2. Remove the clip from this "horseshoe" looking part by pressing the clips in from the other end






3. the other clip that just needs to be jiggled to be removed. the whole black plastic part gets replaced.





4. Spray some PB blaster and wait 5 minutes. Place the O2 sensor removal socket onto sensor and turn counter clockwise with breaker bar. I braced myself against the front left tire and kicked the breaker bar with my feet to loosen.





old o2 sensor.

5. Not shown: the new o2 sensor comes some gold colored anti seize grease. lube up the o2 sensor threads and screw in the new part. clip everything back together.

Next, put an OBD II scanner into the OBD II port and clear the check engine code. I cleared out my P0037 code with my trusty old scangauge 2. Turn the car on, take it for a test drive. tighten the new o2 sensor and you're good to go

Probably would have paid $450 to get this done at lexus. they wanted $250 for the part.
I got the same part online for around $77 bucks, the o2 socket was $15, and the pb blaster was $5.

Now hopefully bank 1 sensor 1 doesn't crap out, because I think that's tucked all the way back by the firewall. If that happens im just going to suck it up, take it toyota and get my spark plugs replaced at the same time since they probably are going to need to remove the manifold and stuff to get to it!!

 

O2 sensors are usually quite easy to get to.

one tip for removal, cut the wire close to the sensor so you can fit a deep socket over it, if there isnt room, use the box end of a wrench. an open wrench will usually slip off.

they make special tools for this too, i have one, about 30 bucks.

and dont forget jack stands.

 

updated with DIY instructions on how to do this. Mods, can you change the title? Also, not sure why two of the images rotated on their own when i uploaded the pics.

 

Nice work. Very clear write-up.

Mods sticky this.

 

evident, Thanks a lot for your instructions and pics.
This weekend my wife's rx350 07 engine check in went on and error code called for B1S2, just exactly your situation. The biggest challenge was to locate the sensor and no way I could do it without your thread, including part numbers.
Local store has no idea which one is B1S2.
Good job

 

Thank you very much for this detailed tutorial. I had the exact same error code on my wife's 05 RX330. Initially i thought i was going to have to take it in for service and since its due for spark plugs figured i'd go ahead and get that done and break the bank but thanks to your post i was able to target the specific issue and get it resolved for a little under $100 altogether. Thanks again.

 

Wow, what a find! Same situation as arsharp84, car threw a CEL, scanned - same code for B1S2! Bought the sensor on rockauto. Actually, bought both, B1S2 and B2S2 as I was told to have them both replaced but, it seems that the B2S2 is way up there and hard to get to... Will look and report back if I am able to replace it as well. Question: What size socket is it? I do not have the O2 sensor socket so will follow the tip and just cut the wire to fit a deep socket over the sensor.

 

Turns out, B2S2 is upfront in the bottom-middle of the car and, actually, easier to get to then to the B1S2! Save yourself some elbow grease and rent a O2 sensor tool kit from Autozone or any other automotive store! Soaked the sensors with PB Blaster for a few minutes and it was relatively easy to unscrew them. Someone told me you could put a propane torch to it and warm it up a little. I did not have to do that.

 

Dear ALL,

i have problem with oxygen sensor bank 2 sensor 1 for lexus RX 350 model 2009.

Can i anyone help me to find the location for Bank 2 sensor 1 with picture if possible and also the spare part#. for the same.


Appreciate your kind assistance.

 

Only cut the wire at the 02 sensor if you are 100% sure that the 02 sensor is bad. Often a "too lean" code for an 02 sensor is vacuum related (crack in a line letting in too much air) and a "too rich" code could be a leaky fuel injector, MAF sensor issue, etc.

 

Bank 2 is the forward exhaust, sensor 1 will be before the catalytic converter. So, it is basically right near the top, pointing to the driver's tire. I'll upload a picture I have that might help.
In this image, the sensor is at the bottom of the picture. This is taken standing in front of the car, looking down between the engine and radiator. This is a fine piece of <explicative deleted> workmanship from Eastern Catalytic that was not more than 15 months in service.
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Add me to this list. Mine popped on yesterday. Time to start looking for a deal on a Denso sensor...

Is the '05 330 in the same place?

 

Depends, both 350 and 330 will have 4. One upper and one lower on each of the 2 banks. Which does you DTC say?

 

It says the same thing discussed here: P0037

 

That will be 2ND sensor bank 1, it will be down under you car. Get under there, remove pans as necessary and follow bank 1 down until you get to the second sensor is best way. Google it and there are diagrams.