The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

So I noticed while installing a lift on my TJ that the bank 1 sensor 2 or it could be bank 2 sensor 2 wiring for the O2 sensor had another plug not plugged into anything. It’s about 4” long and looks similar to the plug that the O2 sensor goes into but it was not in use. Should this be hooked up to something? At quick glance I didn’t see anything from underneath that was disconnected. Is there a service plug or option plug that shares the same wiring loom as the second O2 sensor? I’ll try to get a picture tonight when I’m back under the jeep. I have been getting random misfire codes but Jeep runs great so ¯\_(ツ)_/¯ just seeing if someone else knows what I’m talking about since I don’t 😀.
 
In case anyone was wondering I ended up getting this NTK sensor from NGK.com and they said that they had 125 in stock at time of ordering. Might be worth looking into.

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I’m gonna put this in soon but I can’t get rid of the concern that it only started popping the day after I pulled the battery and PCM to replace the blower motor. It popped, then went out on its own, then popped again yesterday.
 
are there any sensors further down the exhaust system? I understood that there was one just prior to cat converter, underneath skid plate, and another after cat just prior to muffler. Am I wrong, or are these something separate?
 
are there any sensors further down the exhaust system? I understood that there was one just prior to cat converter, underneath skid plate, and another after cat just prior to muffler. Am I wrong, or are these something separate?

Yes, on the '97 through '99 models there are only the 2 O2 sensors.


Edit: For anyone reading this with a 2000
Federal Emissions '00 model year only have 2 sensors in relatively the same place, but they redesigned the exhaust manifold to a 2 piece so the intermediate pipe (the cat is part of this pipe) is different.
 
But that is one of the upstream sensor , And the other one ? Is discontinued, so? What are you going to do? Put only one ? or do you know if you can put two the same for the upstream sensors ?

NTK was really good at using identical sensors and only changing the length of the wires to fit the lower sensors.
If you look at the Walker numbers and cross them over to the NTK sensors you can see which sensors NTK did that with. Walker will list the same part number for sensors that NTK has different numbers for.
 
NTK was really good at using identical sensors and only changing the length of the wires to fit the lower sensors.
If you look at the Walker numbers and cross them over to the NTK sensors you can see which sensors NTK did that with. Walker will list the same part number for sensors that NTK has different numbers for.

So you think that ntk 23179 fits for the two upstream sensors ? I havent been able to crosschek that. Ntk has diferent refs for the upstream sensors, not sure if they have diferent refs and diferent wire lenghts, or they have diferent refs but same wire length
 
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So you think that ntk 23179 fits for the two upstream sensors ? I havent been able to crosschek that. Ntk has diferent refs for the upstream sensors, not sure if they have diferent refs and diferent wire lenghts, or they have diferent refs but same wire length

I would have to cross check them with Walkers numbers to say one way or the other. We, as a collective, have just figured out that's how Walker saves a little coin on manufacturing over the way NTK did it. The likely reason NTK used identical sensors with different part numbers and wire lengths was because they were contracted by Jeep to build to exacting specifications for the Mopar part numbers.
 
I would have to cross check them with Walkers numbers to say one way or the other. We, as a collective, have just figured out that's how Walker saves a little coin on manufacturing over the way NTK did it. The likely reason NTK used identical sensors with different part numbers and wire lengths was because they were contracted by Jeep to build to exacting specifications for the Mopar part numbers.

I undestand , thats the main reason yes
 
Hi Chris, just ran across this thread by chance and it is proven to be super helpful. My only question is how does one go about gaining access to the upstream sensors? My intake is in the way and access is super difficult. Downstream sensors required a lot of torque, so expecting the same from the upstream ones.
 
Just wanted to take a minute to thank the folks on this thread. I just changed all four oxygen sensors on my 2005 LJ and this thread was perfect. Thanks for taking the time.

How did you get to the Bank 2 Sensor 2 plug? I have an 06 LJ and the plug is on top of the transmission. I can’t seem to squeeze my arm in and bend it to get at the plug.
 
How did you get to the Bank 2 Sensor 2 plug? I have an 06 LJ and the plug is on top of the transmission. I can’t seem to squeeze my arm in and bend it to get at the plug.

Not sure if you saw it or not but that post is from August of 17 not to mention it was the only post that member left on the forum.

Now to your dilemma, yep, it's a PITA to get to that plug. First thing you want to make sure of is that it's as clean as you can possibly get it so no dibris is interfering with manipulating the clip once you can get to it.

I don't know that there is a "best way" to get to it, but I seemed to be able to reach it better from below with the drive shaft removed, or at least the front u-joint unbolted and the shaft swung over out of the way.

Hope that helps.