The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

Interesting, I thought most of the later model 2000s by that point had 4 sensors, but maybe I'm wrong. I knew that some 2000s had 2 sensors, and others had 4, but I'm not sure if there's any rhyme or reason to that.

Federal or California doesn't mean anything to my knowledge. The Federal ones should pass inspections just fine, as should the California ones. I've never heard of anyone having any issues with either.
I'm not so much worried about emissions, they're non-existent where I live, I just want to keep the CEL gremlins from harassing me until the ECU gets it's reprogram

Update: Just talked to NGK rep and he had me go to https://ngksparkplugs.com/en/part-finder and use their part finder. It does have listings for Federal and CA emissions.
2000 4.0l 5spd
Federal emissions (Only 2 sensors)
23122 upstream
23099 downstream
 
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Just bought all 4 for Ripley, 200.00 and change, hope she appreciates it and my mileage improves enough to pay for ‘em. Next Tuesday I’ll drop her off and let my mechanic wrestle with them along with my body mount bushings.
 
I'm not so much worried about emissions, they're non-existent where I live, I just want to keep the CEL gremlins from harassing me until the ECU gets it's reprogram

Update: Just talked to NGK rep and he had me go to https://ngksparkplugs.com/en/part-finder and use their part finder. It does have listings for Federal and CA emissions.
2000 4.0l 5spd
Federal emissions (Only 2 sensors)
23122 upstream
23099 downstream

Ohhh, is its check engine lights you’re worried about I wouldn’t worry at all as long as they are NGK sensors.
 
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Ohhh, is its check engine lights you’re worried about I wouldn’t worry at all as long as they are NGK sensors.
I see they list the NGK 23122 for the upstream, before I saw this thread I purchased 23506 which according to their chart that one is for CA emissions. Will I run into problems or will this be ok?
 
I see they list the NGK 23122 for the upstream, before I saw this thread I purchased 23506 which according to their chart that one is for CA emissions. Will I run into problems or will this be ok?

You'll be okay.
 
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While being a YJ guy for the last 23 years, i just got myself into the noble deed of resurrecting a friend's 2002 4.0L Sport, which was rotting away for the last 8 years. After getting the TJ to run again, i witnessed the transition from the last analogue jeep (YJ) to the first digital jeep (TJ) :) :). That means that i have to live with all the chimes and warning sounds and lights! But also with a better ride and more flex!

To cut a long story short, i get a CEL about the upstream O2 sensor. Since the jeep, which is a 2002 Sport with the 4.0L, is an export model (Europe), it has only 2 O2 sensors. One before the cat (upstream) and one after the cat (downstream). I pulled out the problematic upstream sensor and its part number is 56041887AA. Since the OEM is around 175$, I am trying to find the NTK equivalent but without luck. My question is: shall i go for the NTK 23151 (of the 97-99 yr model stated in the beginning of the thread) or is there another NTK part number for a direct replacement to 56041887AA? Any help will be appreciated!
 
While being a YJ guy for the last 23 years, i just got myself into the noble deed of resurrecting a friend's 2002 4.0L Sport, which was rotting away for the last 8 years. After getting the TJ to run again, i witnessed the transition from the last analogue jeep (YJ) to the first digital jeep (TJ) :) :). That means that i have to live with all the chimes and warning sounds and lights! But also with a better ride and more flex!

To cut a long story short, i get a CEL about the upstream O2 sensor. Since the jeep, which is a 2002 Sport with the 4.0L, is an export model (Europe), it has only 2 O2 sensors. One before the cat (upstream) and one after the cat (downstream). I pulled out the problematic upstream sensor and its part number is 56041887AA. Since the OEM is around 175$, I am trying to find the NTK equivalent but without luck. My question is: shall i go for the NTK 23151 (of the 97-99 yr model stated in the beginning of the thread) or is there another NTK part number for a direct replacement to 56041887AA? Any help will be appreciated!

I would use the sensors from the 97-99 models then, since export models to my knowledge never changed over in 2000 and kept the 97-99 emissions all the way until 2006.
 
I would use the sensors from the 97-99 models then, since export models to my knowledge never changed over in 2000 and kept the 97-99 emissions all the way until 2006.

Thanks Chris, i also think it is a one way street solution. I would get the NTK 23151 and if the CEL doesn´t disappear i would go for the OEM part! Cheers
 
Thanks Chris, i also think it is a one way street solution. I would get the NTK 23151 and if the CEL doesn´t disappear i would go for the OEM part! Cheers

Yep, that's what I would do. And just so you know, the OEM Mopar O2 sensors are NGK / NTK :)
 
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Grabbed one for mine yesterday. It's the original as far as I know and approaching 130k miles it can't have much life left. I'd rather change it now vs dead of winter
 
@Chris, save me. I cannot unclip the bank 2/sensor 2 plug. It is driving me insane. I’ve been out there 1.5 hours trying to unplug it. Sensor came out fine, just the plug. It’s in the transmission tunnel. I THINK I know how to unplug it, just press-push-pull. Like on the new one.
09A61A09-1C9E-4AE9-AFA2-DAF863C8CB0D.jpeg

No luck. Any suggestions? Anyone?
277A43B2-BF78-4A76-BB29-435CD3F150F5.jpeg

In the process I unplugged this. Can’t find where it plugs back in now. Anyone know?
339608B0-D54B-45B2-AA0A-EC0F5BAFBDC2.jpeg


I’m working in this area of the engine bay.
EAF1DA04-0996-447E-B0FB-DA21E8F3F89F.jpeg
 
@Chris, save me. I cannot unclip the bank 2/sensor 2 plug. It is driving me insane. I’ve been out there 1.5 hours trying to unplug it. Sensor came out fine, just the plug. It’s in the transmission tunnel. I THINK I know how to unplug it, just press-push-pull. Like on the new one.

That's exactly how you unplug it, unfortunately those connectors can be a son of a bitch when they've been exposed to the elements and never removed before.
 
That's exactly how you unplug it, unfortunately those connectors can be a son of a bitch when they've been exposed to the elements and never removed before.
Well crap! There’s almost no way to get your hand in there. Did you see the rest of my post? I unplugged something else while trying to unplug the O2 sensor plug and don’t know where it goes now. Got tired of looking
 
Well crap! There’s almost no way to get your hand in there. Did you see the rest of my post? I unplugged something else while trying to unplug the O2 sensor plug and don’t know where it goes now. Got tired of looking

I missed that part, I'm not sure where that goes. @toximus or @jjvw knows I'll bet.
 
That's a vacuum line likely from the intake manifold.

Can't help on the plug beyond keeping at it. I wonder if that is the one I didn't fully seat when I changed sensors? Later on, that loose plug led to the ASD relay killing the engine in certain situations.
 
Ok, found where the vacuum line plugged back in. O2 sensor plug still giving me fits. What a bear!
 
Try cleaning the connector with electrical contact cleaner (because it's safe for the plastic and seals).

Sometimes grit works it's way into the connector. It'll mess them up slightly, but you might need to use pliers to get enough grip on them.

Another option is to pull a fender for easier access to that spot.
 
Try cleaning the connector with electrical contact cleaner (because it's safe for the plastic and seals).

Sometimes grit works it's way into the connector. It'll mess them up slightly, but you might need to use pliers to get enough grip on them.

Another option is to pull a fender for easier access to that spot.
I had channel locks on one side and pliers on other several times to no avail. My next idea is to cut that tab off with some wire cutters. I literally can’t push it down. The channel locks seemed to move it down some, but any other method of pressing is futile. I felt stupid even posting this but any idea is worth trying
 
Is it normal for there to be a burning smell after installing a new 02 sensor? I cleared the code, went for a short drive and burning smell started. Wires aren’t touching the transmission.
 
Is it normal for there to be a burning smell after installing a new 02 sensor? I cleared the code, went for a short drive and burning smell started. Wires aren’t touching the transmission.
Wiring? or oily smell? Did you use a penetrating oil before removal? If so did you wash off any left over residue with brake parts cleaner?