Oxygen sensor PO136

[cadreck]

I've got check engine "PO136 code heated oxygen sensor bank 1 sensor2", I have checked 14 ohms resistance on terminals +B and HT of the sensor - as per alldata manual it should be between 11-16 ohm.
OBDII live data shows zero voltage from the sensor though.
Is the sensor gone?
The truck is 2000 4Runner SR5 V6 3.4L auto single cat. converter.
If I need a new sensor what brand is to go with, Denso or NGK?

Thanks.

 

[TheDurk]

The ohm test only confirms that the heater resistance is good. That's one circuit. That does not mean the sensor is working. P0136 does not indicate a heater problem anyway.

If OBDII shows no voltage, either the sensor is toast or its associated wiring is toast.

Only use Denso sensors. Amazon usually has the best prices. You can get the Denso part number here:DENSO Aftermarket Online Catalog Search | Vehicle Parts Search

Then use that number to shop on Amazon.

 

[cadreck]

Is there a way to check the second circuit, perhaps to measure a voltage on other 2 pins?

Thanks for reply.

 

[TheDurk]

Is there a way to check the second circuit, perhaps to measure a voltage on other 2 pins?

Thanks for reply.

With a live scanner, you can look at the waveform. A multi-meter will just freak out because the voltage changes too quickly. You can check the circuit continuity at the ECM behind the glovebox, but the pin-out changes year-to-year. I have for my '99 and '02 is on-line. What year are you? It helps to have vehicle info in your sig so we don't waste time asking.

 

[FdcCal]

Get a new Denso from Sparkplugs.com, don't mess with any of the non-OEM brands. Factory are Denso.

 

[cadreck]

The truck is 2000 4Runner SR5 V6 3.4L 4WD automatic single cat. converter (non California).
I've found DENSO Part #234-4162 selling on Ebay new for $70, is this the right one?

Thanks for help,

 

[TheDurk]

The truck is 2000 4Runner SR5 V6 3.4L 4WD automatic single cat. converter (non California).
I've found DENSO Part #234-4162 selling on Ebay new for $70, is this the right one?

Thanks for help,

Yep. Also on on Amazon for $63.37.

Amazon.com: Denso 234-4162 Oxygen Sensor (Air and Fuel Ratio Sensor): Automotive

Remember, Sensor #2 is the downstream sensor after the cat. Your truck uses the same one in front and back. Don't change the wrong one!

 

[thirstyturtle]

Remember, Sensor #2 is the downstream sensor after the cat. Your truck uses the same one in front and back. Don't change the wrong one!

If I'm getting code P0136 and P0125 but having no loss of power or rough idling issues or poor fuel economy, do you think it's the pre-cat or post-cat O2 sensor that needs replacing?

 

[TheDurk]

If I'm getting code P0136 and P0125 but having no loss of power or rough idling issues or poor fuel economy, do you think it's the pre-cat or post-cat O2 sensor that needs replacing?

P0136 is the post-cat sensor heater--no 'think' about it. Do that and see if the P0125 also goes away. Logic says they are in fact unrelated, but experience says do the more specific fix first, and then reassess.

http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/di/eg5vzfe/cip0136.pdf

http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/di/eg5vzfe/cip0125o.pdf

 

[thirstyturtle]

P0136 is the post-cat sensor heater--no 'think' about it. Do that and see if the P0125 also goes away. Logic says they are in fact unrelated, but experience says do the more specific fix first, and then reassess.

http://tacoma.site40.net/4Runner_96...02rmsour/2002/024runne/di/eg5vzfe/cip0136.pdf

http://tacoma.site40.net/4Runner_96...2rmsour/2002/024runne/di/eg5vzfe/cip0125o.pdf

Well disregarding your advice (but based on other people's experience on the forums and the pre-cat sensor failing more often), I replaced the pre-cat sensor and cleared the code. Before replacing the sensor, clearing the code only kept the CEL away for a day or two. Since I replaced the sensor, the code has been gone for about 2 months.

Today it threw P0136 by itself...I suppose the post-cat sensor must be the problem for sure this time ya?

Just strange that the pre-cat sensor fixed it for a few months...maybe it was the problem and now the post-cat sensor has failed as well. They were both original I suspect as they were practically welded on. Had to have the front sensor cut out and a new bung welded in. I hope the post-cat sensor doesn't require that $160 treatment.

 

[TheDurk]

Well disregarding your advice (but based on other people's experience on the forums and the pre-cat sensor failing more often), I replaced the pre-cat sensor and cleared the code. Before replacing the sensor, clearing the code only kept the CEL away for a day or two. Since I replaced the sensor, the code has been gone for about 2 months.

Today it threw P0136 by itself...I suppose the post-cat sensor must be the problem for sure this time ya?

Just strange that the pre-cat sensor fixed it for a few months...maybe it was the problem and now the post-cat sensor has failed as well. They were both original I suspect as they were practically welded on. Had to have the front sensor cut out and a new bung welded in. I hope the post-cat sensor doesn't require that $160 treatment.

All I can tell you is the front sensor has nothing to do with a P0136. It is specific to the rear sensor heater circuit.(Bank 1 Sensor 2). I can't imagine anyone said different with respect to that specific P-code. And yes, the front sensor usually fails first, but it throws different codes when it does. You may have an intermittent wiring problem on the rear sensor. Other than that, I have no idea why it stayed off.

The good news is you needed to change the front sensor anyway if original. The rear one also owes you nothing. So go ahead and change it and inspect the wiring while you do it. Clean the truckside connector.

 

[sterbenlicht]

The code said it all, sensor two is the second sensor on that side. Bank 1 sensor one is the one pre cat, sensor 2 is the one after the cat. Same goes for bank 2. Then only time this gets hairy is when identifying which is "bank 1" sensor #1/2 and "bank 2" sensor #1/2 on 4cyl.

The code probably went away for a while because it was just beginning to see the issue and finally saw it enough to throw a code. Clearing it means it'll take it a while to repeat it if it's on the way out depending on what's wrong with the sensor. It's a super common problem though, and usually not worth trying to diagnose with meters.

Also, usually the pre-cat sensor will cause driveability issues. The post-cat sensor's only function is causing a CEL to let you know the cat isn't functioning properly. If the second one goes bad, you usually won't notice anything aside from the CEL. The first one is technically an A/F sensor and is used to give the computer readings from the exhaust it can use to keep everything running correctly.

 

[thirstyturtle]

Thanks fellas! You've confirmed what I thought, I'll order the sensor today and HOPEFULLY this time I'll be able to get the sensor off without having to take it to a shop.

 

[sterbenlicht]

Soak it down. I would also purchase a special sensor socket if you don't have one already.

 

[thirstyturtle]

Soak it down. I would also purchase a special sensor socket if you don't have one already.

I soaked it a bit this morning and will probably hit it every day until the sensor arrives on Friday.

What is the "special sensor socket" that you suggest?

 

[TheDurk]

I soaked it a bit this morning and will probably hit it every day until the sensor arrives on Friday.

What is the "special sensor socket" that you suggest?

Won't work on a flange type socket like you have on your 2000. Those are for screw-in type sensors which are only found on '01-'02 rear sensors.

 

[thirstyturtle]

Won't work on a flange type socket like you have on your 2000. Those are for screw-in type sensors which are only found on '01-'02 rear sensors.

10-4, hope this clears the code up once and for all (or at least another 14 years).

 

[sterbenlicht]

Won't work on a flange type socket like you have on your 2000. Those are for screw-in type sensors which are only found on '01-'02 rear sensors.

Ah yes, good point. I completely forgot these are different haha.

 

[masphx]

Yep. Also on on Amazon for $63.37.

Amazon.com: Denso 234-4162 Oxygen Sensor (Air and Fuel Ratio Sensor): Automotive

Remember, Sensor #2 is the downstream sensor after the cat. Your truck uses the same one in front and back. Don't change the wrong one!

Will this one work for my upstream in my 1998 5speed? Amazon says it is not a match for my rig. A few times I have had a pending PO133 but then it goes away. Not sure if the O2 sensor has been replaced but at 203K and at lesser and lesser good fuel economy I would like to replace.

 

[JayRolla]

Will this one work for my upstream in my 1998 5speed? Amazon says it is not a match for my rig. A few times I have had a pending PO133 but then it goes away. Not sure if the O2 sensor has been replaced but at 203K and at lesser and lesser good fuel economy I would like to replace.

I just did mine on my 96. No more CEL. Per URD you should use this 234-4161. 4162 is for the auto.
https://urdusa.com/index.php?cPath=9_13