The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

TJ_Jake

New Member
Nov 22, 2018
21
8
Jamestown NC
Feel your pain LJ. I balled mine too. Before I give up, I’m going to try an old hot rodders trick with a Mapp Torch and some candle wax. Apparently the wax gets so hot when you touch it to red hot parts that it sucks it into the threads wicking it around and providing lubrication. Then I’m going to take a pipe wrench and get medieval on it. The guy who uses this technique said that you may have to try it multiple times. I realize you don’t have one but they can be had at Lowe’s or Home Depot with the Mapp and Torch for under 20 bucks. I’ll do this a few more time before taking it to the muffler shop on the corner. So wishing I had ordered the Kroil oil like Chris suggested. It would have come in the mail by now LOL
 
OP
OP
Chris

Chris

Administrator
Staff Member
Sep 28, 2015
31,836
19,413
Salem, Oregon
It might be time to drive to an exhaust shop, even if it means going out of your way. With a lift and the proper tools, it will come off. Either that or they can easily weld in a new bung and weld up the old one.
 
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Jeepers-N-Creepers

Have mud--will travel.
Supporting Member
Nov 5, 2018
162
176
Texas
Confession :(:

1543855191220.png


Early on in my TJ ownership (on the heels of a thoroughly enjoyable 6-year WJ ownership), I met with a protracted Oxygen Sensor saga.

I had entered into a maniacal game of "Whack-a-Sensor" (not unlike "Whack-a-Mole"). After several months, and in an exasperated state, I placed the world on-hold; I then donned my Carhartt coveralls and slid under the engine--but not before "dime'ing-out" (i.e., volume level "10") Dream Theater - "live."

1543855605331.png


While gritting my teeth and expelling callous four-letter words, I excised all sensors. Rather than simply discarding them, I then went to the litter box, which is frequented by my 2 cats, one of which is 20 lbs. I then laterally excised several of their "federal tax returns" (I refer to their "offerings" as federal tax returns) with a scooper, and placed them in the same bag with the sensors--ensuring that the sensors would suffer an eternity as I placed the mixed contents in the garbage.

I then plugged each oxygen sensor cavity with JB Weld.

After the JB Weld sat overnight, I took the Jeep for a long drive. No engine light. The engine light had appeared to re-set itself. I was then in a blissful state, while repeatedly self-affirming my creative wisdom. I then begin to whistle the tune, "What a Wonderful World," by Louis Armstrong.

1543857435444.png


Three weeks later, and during a beautiful Spring day, I was on a long trek into the countryside, continuing to marvel over my ingenuity. The flowers were sporting radiant colors, the birds were chirping, and the 4.0L was humming beautifully--when all of the sudden I noticed the engine light--again.

I pulled over, shut the Jeep off, and ran into open meadow--screaming like a madman. In fact, I do believe I was entering a state of optimal "Primal Scream":

1543856673880.png


I was found, nestled in a bed of daisies, as the sun was going down, by a good-natured local Sheriff, who asked if I needed a ride home. Declining the ride home, I sauntered to my Jeep and drove home in a posture of despair and resignation. I think I was weeping, and drooling as well (I rarely drool).

In the morning, I drove to a garage, whereupon they placed the dreaded meter on the ECU. The mechanic met with an engine code which read:

"YDA"

Upon inquiry, the mechanic explained to me that "YDA" stood for:

"You Dumb @$$!

And so the ongoing saga of my love-hate relationship with my TJ.

I am now in a 12-Step Recovery Group for TJ owners. My typical introduction therein?

"Hi, my name is 'Jeepers-N-Creepers,' I think I need to buy another part."


1543857031441.png
 
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TJ_Jake

New Member
Nov 22, 2018
21
8
Jamestown NC
:) I want to plug them up too. It’s supposed to be such an archaic vehicle. A legendary 4.0 whose roots go back to the AMC late 50s I believe, yet here I am staring at an anomaly.... wireless rail spark distribution and 4 sensors that bring the Jeep into the 21st century I suppose. I dare say... still easier to wrench on than my Mazda. Not apples to apples but scoring a brake cylinder for under 10 bucks?! For the most part we got it good with inexpensive parts (compared to other vehicles) except for that bank 2 downstream sensor that has been rusted to my 2001 TJ since the Jurassic period. I am going to try one last time with a pipe wrench.
 

Jeepers-N-Creepers

Have mud--will travel.
Supporting Member
Nov 5, 2018
162
176
Texas
:) I want to plug them up too. It’s supposed to be such an archaic vehicle. A legendary 4.0 whose roots go back to the AMC late 50s I believe, yet here I am staring at an anomaly.... wireless rail spark distribution and 4 sensors that bring the Jeep into the 21st century I suppose. I dare say... still easier to wrench on than my Mazda. Not apples to apples but scoring a brake cylinder for under 10 bucks?! For the most part we got it good with inexpensive parts (compared to other vehicles) except for that bank 2 downstream sensor that has been rusted to my 2001 TJ since the Jurassic period. I am going to try one last time with a pipe wrench.
Here's wishing you the utmost volition of your personal will--combined with the utmost of your patience:)
 

Willys LJ

TJ Enthusiast
Oct 26, 2018
102
99
Dyer TN
Confession :(:

View attachment 66235

Early on in my TJ ownership (on the heels of a thoroughly enjoyable 6-year WJ ownership), I met with a protracted Oxygen Sensor saga.

I had entered into a maniacal game of "Whack-a-Sensor" (not unlike "Whack-a-Mole"). After several months, and in an exasperated state, I placed the world on-hold; I then donned my Carhartt coveralls and slid under the engine--but not before "dime'ing-out" (i.e., volume level "10") Dream Theater - "live."

View attachment 66237

While gritting my teeth and expelling callous four-letter words, I excised all sensors. Rather than simply discarding them, I then went to the litter box, which is frequented by my 2 cats, one of which is 20 lbs. I then laterally excised several of their "federal tax returns" (I refer to their "offerings" as federal tax returns) with a scooper, and placed them in the same bag with the sensors--ensuring that the sensors would suffer an eternity as I placed the mixed contents in the garbage.

I then plugged each oxygen sensor cavity with JB Weld.

After the JB Weld sat overnight, I took the Jeep for a long drive. No engine light. The engine light had appeared to re-set itself. I was then in a blissful state, while repeatedly self-affirming my creative wisdom. I then begin to whistle the tune, "What a Wonderful World," my Louis Armstrong.

View attachment 66240

Three weeks later, and during a beautiful Spring day, I was on a long trek into the countryside, continuing to marvel over my ingenuity. The flowers were sporting radiant colors, the birds were chirping, and the 4.0L was humming beautifully--when all of the sudden I noticed the engine light--again.

I pulled over, shut the Jeep off, and ran into open meadow--screaming like a madman. In fact, I do believe I was entering a state of optimal "Primal Scream":

View attachment 66238

I was found, nestled in a bed of daisies, as the sun was going down, by a good-natured local Sheriff, who asked if I needed a ride home. Declining the ride home, I sauntered to my Jeep and drove home in a posture of despair and resignation. I think I was weeping, and drooling as well (I rarely drool).

In the morning, I drove to a garage, whereupon they placed the dreaded meter on the ECU. The mechanic met with an engine code which read:

"YDA"

Upon inquiry, the mechanic explained to me that "YDA" stood for:

"You Dumb @$$!

And so the ongoing saga of my love-hate relationship with my TJ.

I am now in a 12-Step Recovery Group for TJ owners. My typical introduction therein?

"Hi, my name is 'Jeepers-N-Creepers,' I think I need to buy another part."


View attachment 66239
ROFLMAO! Sounds like something I'd have done back when I was prone to that kind of thing.

I haven't attacked that stubborn last one again due to other stuff having gotten between me and it. But it's giving me time to think of other ideas.

I've got a couple of impact wrenches (3/8 & 1/2") but not much air compressor capacity, but it's good for short bursts which in my case is probably a good thing. If I go that route, I'll try the "lil 'un" first, then on the "big 'un".
 

Jeepers-N-Creepers

Have mud--will travel.
Supporting Member
Nov 5, 2018
162
176
Texas
ROFLMAO! Sounds like something I'd have done back when I was prone to that kind of thing.

I haven't attacked that stubborn last one again due to other stuff having gotten between me and it. But it's giving me time to think of other ideas.

I've got a couple of impact wrenches (3/8 & 1/2") but not much air compressor capacity, but it's good for short bursts which in my case is probably a good thing. If I go that route, I'll try the "lil 'un" first, then on the "big 'un".
:sisi1
 
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Willys LJ

TJ Enthusiast
Oct 26, 2018
102
99
Dyer TN
Well, I got a reprieve of sorts. While it was warm and I had the LJ in my shop, I also installed a new radio along with all but the one O2 sensor. And I disconnected the battery while doing that. After I finished and started it up, I got the CEL again and wasn't surprised considering the crap I'd dished out on the 4th sender.

The CEL went off (bulb still works) yesterday morning and has stayed out so far. I drove it over about half the county yesterday afternoon so it has had ample time to come back on. Guess I need to hook the OBD reader again and see what's up.

It might be trying to do me like Jeepers Creeper's TJ did him. Jeeps can be sneaky like that.

I forgot to mention on the front driveshaft that I just unhooked it from the axle and swung to the side out of the way. I didn't disconnect it from the t/c.
 
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TJ_Jake

New Member
Nov 22, 2018
21
8
Jamestown NC
That’s great. Glad you got something working... Wins are important when an O2 sensor is stubborn. Mine like yours is the downstream bank 2. When I reconnect the batt, the CEL stays out for a couple of days but then comes back on. I’m going to come back to it after I chase the coolant leak which appears to be leaking due to using worm gear clamps on the lower rad hose. I’ve ordered the constant tension spring clamps per Jerry and Chris’s advice. They are what the manual calls for. So I was surprised when I called my local Jeep dealer to see if I could swing by and purchase one from Parts and was told that all they carry are the universal worm clamps!
 
Last edited:

kevcam

New Member
Dec 6, 2018
1
0
Ashburn, VA
What are Bank 1, Bank 2, etc.?
Since this question pops up from time-to-time, here's an easy to follow diagram that illustrates what they mean when your OBDII code scanner (or manual) tells you something like "O2 sensor, Bank 1, Sensor 2":

View attachment 12208


What does upstream and downstream mean?
Simple, upstream means the O2 sensor is "upstream" of the catalytic convertors, meaning before the catalytic convertors. Downstream means the O2 sensor is "downstream" of the catalytic convertors, meaning after the catalytic convertors.


What brand of O2 sensors should I use for replacements?
Pay close attention to this one so you can do it once and do it right! The Jeep Wrangler TJ is extremely sensitive to all oxygen sensors other than NGK / NTK. Bosch O2 sensors and all the others (including the crappy Chinese brands you'll buy at your local auto part store) are very well documented as not working properly with our TJs. In other words, you plug them in and you assume all is well, until you notice your check engine light isn't going away. This is almost always due to the fact that you didn't use an NGK / NTK replacement O2 sensor.


Okay, so why don't other sensors (i.e. Bosch) work on our Jeeps?
Glad you asked! Check out this video for a detailed explanation of why other brands of O2 sensors don't work on our TJs:



So which O2 sensors do I need?
I'm going to break down which sensors you need based off what year your TJ is. The part numbers (and information) below were taken directly from the NGK website, so you can assure it is 100% accurate (even double checked each individual year and model before writing this thread).


4 Cylinder Engines
1997-2000
NGK #23506 - Bank 1, Sensor 1 (Upstream)​
NGK #23151 - Bank 1, Sensor 1 (Upstream) (1998 ONLY)​
NGK #23099 - Bank 1, Sensor 2 (Downstream)​
2001-2004
NGK #23138 - Bank 1, Sensor 1 (Upstream)​
NGK #23141 - Bank 1, Sensor 2 (Downstream)​
2005-2006
NGK #23159 - Bank 1, Sensor 1 (Upstream)​
NGK #23159 - Bank 1, Sensor 2 (Downstream)​
6 Cylinder Engines
1997-1999
NGK #23151 - Bank 1, Sensor 1 (Upstream)​
NGK #23099 - Bank 2, Sensor 2 (Downstream)​
2000
NGK #23122 - Bank 1, Sensor 1 (Upstream)​
NGK #23506 - Bank 2, Sensor 1 (Upstream)​
NGK #23099 - Bank 1, Sensor 2 (Downstream)​
NGK #23099 - Bank 2, Sensor 2 (Downstream)​
2001-2003
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)​
2004
NGK #23137 - Bank 1, Sensor 1 (Upstream)​
NGK #23135 - Bank 2, Sensor 1 (Upstream)​
NGK #23132 - Bank 1, Sensor 2 (Downstream)​
NGK #23531 - Bank 2, Sensor 2 (Downstream)​
2005-2006
NGK #23018 - Bank 1, Sensor 1 (Upstream)​
NGK #23160 - Bank 2, Sensor 1 (Upstream)​
NGK #23159 - Bank 1, Sensor 2 (Downstream)​
NGK #23158 - Bank 2, Sensor 2 (Downstream)​
Misc Installation Notes
When installing new O2 sensors, be certain to use some anti-seize on the threads of the new O2 sensors! This is important, and will save you a huge headache should you ever need to remove them in the future.

In addition, a O2 sensor socket will greatly aide in the installation and removal of O2 sensors. I recommend this one.
I'm a touch confused and hoping someone can help. I have an error code that reads O2 sensor circuit high voltage bank 1 sensor 2. I have a '98 6 cyl. I don't see a listing for bank 1 sensor 2 above for the 6 cyl. Can someone point me in the right direction? Thanks!
 
OP
OP
Chris

Chris

Administrator
Staff Member
Sep 28, 2015
31,836
19,413
Salem, Oregon
I'm a touch confused and hoping someone can help. I have an error code that reads O2 sensor circuit high voltage bank 1 sensor 2. I have a '98 6 cyl. I don't see a listing for bank 1 sensor 2 above for the 6 cyl. Can someone point me in the right direction? Thanks!
Your 98 has only 2 O2 sensors, whereas the later models have 4.

The only two O2 sensors you have are as follows:

NGK #23151 - Bank 1, Sensor 1 (Upstream)
NGK #23099 - Bank 1, Sensor 2 (Downstream)

I updated the original post to reflect this, as it was merely a typo on my part (though the part numbers were correct).

I'd replace both at the same time, it's the smart thing to do.
 
Nov 22, 2018
21
8
Jamestown NC
Latest update from downstream bank 2. Half of the sensor is out. Ceramic / nut / probe still intact. Sprayed some Sea Foam Deep Creep gave it an obligatory tap. Gonna get this baby out before scheduling a c section at the muffler shop. Considering dipping my drill on some oil and drilling a hole through the sensor and working it out some more. I’ve used hot wax too woo this puppy but it’s not budging. Meanwhile in coolant leaky news the spring clamps are getting here tomorrow. Foot of snow here to add to the shade tree fun!
 
Nov 22, 2018
21
8
Jamestown NC
It’s two. Chris recommends NGK, I believe. I would check your VIN to see exactly when yours was built because the 98 appears to be a different part just to be sure. See page 1-2 for the table and more info. Good luck. Mine is still stuck.
 

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