Where is bank 1 sensor 2?

I have to change my third 02 sensor this year. Do they usually go out in succession? Anyways, anyone know which one is bank one sensor two? Drivers side downstream? Thanks!

 

https://www.google.com/search?q=tac...GNC4xOC4xmAEAoAEBsAEKyAEKwAEB&sclient=gws-wiz

 

Isn’t that for first gen? Is it the same?

 

Bank 1, sensor 2 is the rear sensor, behind the catalytic.

Bank 1 sensor 1, is the front one near the engine, depending on the model year, an Air/Fuel sensor (2000 and after) or a regular o2 sensor (before 2000)

Only get DENSO sensor. Toyotas are known to be picky with other brands

 

^^^

 

https://www.google.com/search?q=tac...yAEKwAEB&sclient=gws-wiz#imgrc=bfdYWNNNCwLs4M

 

if im not mistaken the 4.0 v6 cylinders go like this:

5 - 6
3 - 4
1 - 2

So bank 1 would be passenger side sensor 2 is downstream

 

The cylinders order are correct but on the Tacoma's 4.0 along with many toyota engines, Bank 1 is located on the same side as cylinder 1(driver's side). Sensor 1 is pre cat /sensor 2 is after cat.

OP, you are correct. (B1S2) O2 sensor is located on driver's side after cat. As suggested, stick with Denso.

 

Per what you said wouldn't that make bank 1 on the passenger side? Since cylinder 1 is on passenger side? Bank 1 is on the side with the forward most cylinder, correct?

 

You are right. Brain fart. Sorry OP, disregard previous post. Sensor is on passenger side after cat. Thanks Strictlytoyz for the correction. One too many beers right now.

 

No hard feeling brotha! I've been there haha, cheers!

 

If they are all high mileage then it's a matter of time before they start going out in succession. The rears do not go out as often as the fronts, but they do go out on occasion.

If you are having rear oxygen sensor problems AND you have high mileage on an early gen 2nd gen, I would strongly suggest you take a look at the cylinder head gasket on bank 1 and get a cylinder leakage test on that side before replacing that sensor.

 

I just replaced this one 6 months ago ‍♂️

 

Why are you changing it? What makes you think it's bad? What code are you getting?

 

P0138

 

Swap your downstream sensors and see if the problem follows to the other side.

 

Yep. Before you do anything outside of testing and replacement this is a viable option and a valid test.

Just make sure you clear the code and re- run it to see where the code repopulates.

 

P0138 says it could be an injector problem. It says it’s a lean issue. You think it would be compression or exhaust from the head instead of a bad injector?

 

Its hard to say without knowing anything more than we do. I would do what I suggested above first. Swap the sensors. Clear the code and go for a drive. Will give us more info if it comes back with the same or different code.

 

Yes. You need to make sure engine integrity is ruled out. P0138 bank 1 sensor 2 oxygen sensor if that is the code description that is indeed what the label is via FSM or similar then it is a symptom code not a cause code. I say this based upon the prior test described above. Do a quick swap and see where the code lands, if it's still the same code you may have a big problem on your hands at which point I would take a hard look at the engine integrity via cylinder leakage test.