The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

Just replaced all four of my O2 sensors in my '06 with the appropriate NTK's. I was really surprised to find that all for came out VERY easily. I used the O2 socket that @Chris recommended in the original post and it worked well, along with a combination of a 3/8 drive breaker bar, 3/8 ratchet and a small adjustable wrench depending on how much room I needed. I didn't even spray any Kroil or anything on them. I wanted to see what I was headed for so I just put the tool on one to see how tight they were. It broke free relatively easily, so I tried the other three and they all broke free easily. One they were all loose I could turn them out by hand. I don't think I needed to based on how easily they came out, but since I had the tool, I chased the threads with a M18 thread tool. The beauty of not living in the salt belt. : ) Honestly, the hardest part for me was getting that rear post cat connector that's between the engine and firewall disconnected.

For those that have replaced them, did you torque them?

The papers in my sensor boxes said to turn them 1/2 to 3/4 turn after hand tight. It did list a torque, but I don't know if it meant that 1/2 to 3/4 past hand tight was equal to that or what. I just did 1/2 turn after hand tight for now. I don't know if I can get my torque wrench in there to do it, but I ran out of time to try before having to get ready for work.
 
MountaineerTom said:
Just replaced all four of my O2 sensors in my '06 with the appropriate NTK's. I was really surprised to find that all for came out VERY easily. I used the O2 socket that @Chris recommended in the original post and it worked well, along with a combination of a 3/8 drive breaker bar, 3/8 ratchet and a small adjustable wrench depending on how much room I needed. I didn't even spray any Kroil or anything on them. I wanted to see what I was headed for so I just put the tool on one to see how tight they were. It broke free relatively easily, so I tried the other three and they all broke free easily. One they were all loose I could turn them out by hand. I don't think I needed to based on how easily they came out, but since I had the tool, I chased the threads with a M18 thread tool. The beauty of not living in the salt belt. : ) Honestly, the hardest part for me was getting that rear post cat connector that's between the engine and firewall disconnected.

For those that have replaced them, did you torque them?

The papers in my sensor boxes said to turn them 1/2 to 3/4 turn after hand tight. It did list a torque, but I don't know if it meant that 1/2 to 3/4 past hand tight was equal to that or what. I just did 1/2 turn after hand tight for now. I don't know if I can get my torque wrench in there to do it, but I ran out of time to try before having to get ready for work.
Click to expand...

I only did my O2 sensors hand tight. There's no reason or need to torque them. Hopefully you put anti-seize on them!
 
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My TJ is 2002, 6 cylinder.
I have already received the O2 sensors (NJK). The mechanic surprised me ... He informed me that I did not have catalytic convertor !! That he had inspected the car but did not find a catalytic convertor ...!?!. Is it possible...? Is there anyone who has a model from 2001 to 2003 that changed the 4 o2 sensors and did he encounter any problem ...?
 
Medali said:
My TJ is 2002, 6 cylinder.
I have already received the O2 sensors (NJK). The mechanic surprised me ... He informed me that I did not have catalytic convertor !! That he had inspected the car but did not find a catalytic convertor ...!?!. Is it possible...? Is there anyone who has a model from 2001 to 2003 that changed the 4 o2 sensors and did he encounter any problem ...?
Click to expand...

Your country may not require catalytic convertors, which is probably the reason you don't have them.

Here in the U.S., all TJs have them, unless someone removed them.
 
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Chris said:
Your country may not require catalytic convertors, which is probably the reason you don't have them.

Here in the U.S., all TJs have them, unless someone removed them.
Click to expand...
Could this have an influence on the installation of the new O2 sensors ...?
 
Medali said:
Could this have an influence on the installation of the new O2 sensors ...?
Click to expand...

Well, the post-cat O2 sensors will still show check engine lights unless you disable the post-cat O2 sensors via the PCM (you need software to do this such as the HPTuner MPVI2). If yours came with catalytic convertors and someone removed them, then you'll have check engine lights regardless of whether you install new O2 sensors, as the post-cat O2 sensors will be expecting catalytic convertors there.

If you don't have emission testing in your country, then the smart thing to do would be to disable the post-cat O2 sensors via the PCM, then you can remove the 2 post-cat O2 sensors completely and just install new pre-cat O2 sensors (the upper 2).

That's what I did on mine.
 
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Chris said:
Well, the post-cat O2 sensors will still show check engine lights unless you disable the post-cat O2 sensors via the PCM (you need software to do this such as the HPTuner MPVI2). If yours came with catalytic convertors and someone removed them, then you'll have check engine lights regardless of whether you install new O2 sensors, as the post-cat O2 sensors will be expecting catalytic convertors there.

If you don't have emission testing in your country, then the smart thing to do would be to disable the post-cat O2 sensors via the PCM, then you can remove the 2 post-cat O2 sensors completely and just install new pre-cat O2 sensors (the upper 2).

That's what I did on mine.
Click to expand...
Thank you for your advices.
In my country we don't have emission testing... And I don't have any problem of check engine light... But my real problem is with my bad fuel economy... That's for this reason that I bought news o2 sensors.
 
Medali said:
Thank you for your advices.
In my country we don't have emission testing... And I don't have any problem of check engine light... But my real problem is with my bad fuel economy... That's for this reason that I bought news o2 sensors.
Click to expand...

Yes, the new O2 sensors should help with fuel economy to some degree. Of course you still have to understand that with a lift and big tires, you're going to get pretty poor fuel economy to begin with. These things are definitely bad vehicles for fuel economy.
 
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Hi Chris
Your info has been very helpful, I am looking at replacing my sensors on my 05 wrangler unlimited with 85,000 on it and one of the ones you listed keeps coming back as not compatible for my jeep but the other 3 are compatible
2005-2006
NGK #23018 - Bank 1, Sensor 1 (Upstream)
NGK #23160 - Bank 2, Sensor 1 (Upstream)
NGK #23159 - Bank 1, Sensor 2 (Downstream) This one pops up as not compatible
NGK #23158 - Bank 2, Sensor 2 (Downstream)

Thanks again this has been a great thread
Don
 
Hi,
I got a P0141 error to replace sensor Bank 1/sensor 2.
I bought all 4 O2 sensors for my TJ 2001 4.0L Automatic Sahara, right wheel drive (Exported). I double checked with Rockauto and also NGK website to be sure I get the right sensors.
NGK #23139 - Bank 1, Sensor 1 (Upstream)
NGK #23138 - Bank 2, Sensor 1 (Upstream)
NGK #23142 - Bank 1, Sensor 2 (Downstream)
NGK #23141 - Bank 2, Sensor 2 (Downstream)
My mechanic guy searched thoroughly under the vehicle and insisted that there only 2 sensors to replace, one before the catalyst and one after.
What are we missing? where are the other sensors located? the diagram on the first post here doesnt look like what I have in regards to sensor location. am I supposed to use only 2 sensors, like a 4 cylinder engine? many thanks for the help.
 
Phuket said:
Hi,
I got a P0141 error to replace sensor Bank 1/sensor 2.
I bought all 4 O2 sensors for my TJ 2001 4.0L Automatic Sahara, right wheel drive (Exported). I double checked with Rockauto and also NGK website to be sure I get the right sensors.
NGK #23139 - Bank 1, Sensor 1 (Upstream)
NGK #23138 - Bank 2, Sensor 1 (Upstream)
NGK #23142 - Bank 1, Sensor 2 (Downstream)
NGK #23141 - Bank 2, Sensor 2 (Downstream)
My mechanic guy searched thoroughly under the vehicle and insisted that there only 2 sensors to replace, one before the catalyst and one after.
What are we missing? where are the other sensors located? the diagram on the first post here doesnt look like what I have in regards to sensor location. am I supposed to use only 2 sensors, like a 4 cylinder engine? many thanks for the help.
Click to expand...
Not the same problem but similar problem with my 2002 4.0 l sport automatic.
The mechanic found only one downstair Sensor installed but no upstairs one ... He did not find a free electric box either to be able to install other O2 sensors and to connect them with the central computer ( PCM) ... And before that he had not found a catalytic converter ... Always looking for ... I look forward to a solution to this problem
 
Thanks for this thread. I had already ordered some cheap sensors from RockAuto but hadn't yet installed them. I'm returning them and buying the NTKs.
 
I had to ask, I thought that it would be a tuning software-type thing.

I wonder if the "non-fouler" trick would work on our TJ's.

Thanks.
 
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