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  Topic Review (Newest First)
04-20-2017 11:49 PM
Rburkhart_is300 Just curious if anyone has the Denso part # for the 2 pre cat O2s. Ordering them off Amazon and just wanna make sure I get the right one. Thanks!
11-21-2016 04:32 PM
naragon94 I think it should be noted that on both banks, sensor 1(precat, upstream) is the one that will effect performance. B1S2 and B2S2 (post cat, downstream) really only need to be replaced if you live in an emissions county.

Also, when it comes to getting these little b****** off, PB Blaster seemed to work wonders. Also, my local Autozone had a o2 sensor socket set that they rented out to me. This made it super easy for me. Especially B2S1(beside firewall).
11-01-2016 11:30 AM
Originally Posted by dallison View Post
I've got that, but there is limited space to work.
You can use a wrench, then lock another wrench on it to use as leverage. You'll need to disconnect it and slip the ring side of the wrench in.
11-01-2016 07:31 AM
MALAWI Very helpfull info that i'm using it to fixe my car! thank you.
03-02-2016 02:44 PM
Originally Posted by trd_inside View Post
You need to use an O2 sensor socket. It's a socket with a slot on the side for the wires to pass through. You can buy them at any auto parts store.
I've got that, but there is limited space to work.
03-02-2016 08:27 AM
Originally Posted by dallison View Post
How did you guys get b2s1 sensor out? Trying to do it with the socket seems inpossible. Do i need to use a wrench for that one?
You need to use an O2 sensor socket. It's a socket with a slot on the side for the wires to pass through. You can buy them at any auto parts store.
03-02-2016 03:15 AM
Originally Posted by Baphometpwnsyou View Post
Good brand? I always go to autozone

Denso. Autozone is always overpriced I've found. Amazon or Rock Auto is your best bet.
03-01-2016 08:49 PM
Baphometpwnsyou Good brand? I always go to autozone
02-09-2016 04:57 AM
Originally Posted by lextasy23 View Post
Here's my problem: All sorts of codes (6 total...)
P0130 - B1S1 Sensor Circuit Malfunction
P0133 - B1S1 Sensor Circuit Slow Response

P0141 - B1S2 Heater Circuit Malfunction

P0150 - B2S1 Sensor Circuit Malfunction
P0153 - B2S1 Sensor Circuit Slow Response

P0161 - B2S2 Heater Circuit Malfunction

It seems to me like there's a pattern here - both upstream sensors show a malfunction and slow response. Both downstream sensors have a heater circuit malfunction... Could this be because of something else? The heaters have fuses, right? Does anyone know where they are on this car?

I don't want to replace 4 oxygen sensors if I don't have to. I got the car a year and a half ago, and it had O2 codes then (less, forget which ones), at 126k. It has 172k now, and the 6 codes. I'm just afraid replacing all 4 sensors is a waste if I don't have to... ya know?

Any help is appreciated!
Old thread revival!!! Has this problem been fixed?? If so, how?
02-08-2016 08:53 AM
Originally Posted by jasonm4 View Post
You can unplug both B1S2 and B2S2 with no problems or effect on performance besides a CEL. Those two sensors only monitor cat performance, that's it.
On some OBD-II vehicles, the post-cat (S2) o2 sensors are indeed used for fine fuel trim corrections, not only for the cat monitoring. According to some sources, some Toyotas are affected.

Is there any trustworthy evidence that it's not the case with our car?

I read many o2 sensor related discussions here and saw forum members reporting better performance and fuel mileage after fixing S2-related codes like P0161 or P0141 by replacing the affected sensor. How could this be explained?
01-27-2016 01:30 PM
dallison How did you guys get b2s1 sensor out? Trying to do it with the socket seems inpossible. Do i need to use a wrench for that one?
08-07-2015 08:40 AM
onebratt08 I would be careful with the simulators. I had one on my car for years and it worked fine. I had actually forgotten that we installed it. My car recently needed some major repairs (cats and new O2 sensors) and that simulator caused a lot of confusion. It caused the computer to keep throwing O2 sensor codes after all the sensors were replaced. The shop couldn't figure it out. It wasn't until I was looking around here and saw some posts about the simulator that I remembered that my car has one. I thought it was a long-shot, but told the shop about it. After the removed it, the last code cleared. They "shamed" me telling me that I could have ruined my computer...and I am $2200 poorer and spent 10 days without a car. I suspect given the age and mileage of my car, the cats needed replaced anyway, but the extra trouble cost me an extra $600. The O2 sensors are relatively cheap...not much more than I recall paying for the simulator. I wish I had been smart enough years ago to replace the sensor, rather than put the simulator on.
05-03-2015 02:46 PM
tinku There are thick ones that are really plug n play and do not need repining or splicing. They are actually not that expensive they are around 80 something dollars

12-26-2014 11:04 PM
denso o2 part numbers

Find My Part | DENSO Auto Parts
10-09-2014 03:34 PM
IanH Well I finally got round to replacing one of my O2's (B1S1) with the Denso part 234-4209. The wires color codes matched up fine. Note the Denso has crimp connectors in the box, When I tried to solder I found out the wires do not solder well, the wires do not want to wet and are probably not a copper alloy.
So just crimp them in to the original harness.
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