The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

L J

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Which one is bank 1 sensor 1 ect...

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eltavo619

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With regards to your postulation concerning the quality of AutoZone sensors compared to "OEM" which ARE NGK/NTK just
re-boxed with a Mopar number. Have you bothered to read all the information within this thread about why NGK/NTK is the only one recommended to use? It is the exact same part as "OEM" just in the original manufacturers own box and numbers. The aftermarket "AutoZone) sensors are a hit and miss crap shoot as to whether or not they will turn a check engine light off or allow the vehicle to run correctly. These Jeeps are NOT forgiving with aftermarket sensors in the slightest.


I think you'll find the OEM numbered parts are going to be slightly more expensive than the NGK/NTK part no matter where you buy them. NGK is your best option for finding the lowest price though... whether it's through Amazon, parts stores, or places like RockAuto...

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exec98

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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).

Be aware that NTK O2 sensors are identical to NGK and they share the same part numbers. NTK is more common so it will usually be easier to find. Use the same part numbers for NTK as shown below.


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 1, Sensor 2 (Downstream)​

2000 Federal Emissions (Non-Export)
NGK #23122 - Bank 1 Sensor 1 (Upstream)​
NGK #23099 - Bank 1 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.

Lastly, if you notice your O2 sensor harnesses are not long enough with the new O2 sensors, these extensions will solve the problem:

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When I look up sensor that you referenced for a 1998 6cylinder TJ it says that the NGK #23151 - Bank 1, Sensor 1 (Upstream) doesn’t fit my Jeep. Was this a misprint or parts companies wrong. Please advise what you recommend for a 1998 wrangler 6cyl TJ?
 
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Chris

Chris

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When I look up sensor that you referenced for a 1998 6cylinder TJ it says that the NGK #23151 - Bank 1, Sensor 1 (Upstream) doesn’t fit my Jeep. Was this a misprint or parts companies wrong. Please advise what you recommend for a 1998 wrangler 6cyl TJ?

Amazon must be wrong then. I pulled the numbers directly from the NGK website. This happens from time-to-time with Amazon.
 
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Rustynj

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how did you get to the 1/1 and 2/1 sensors? it is really tight in there. I'm dreading having to get those out

I took my jeep to pep boys to get a new wheel put on. While it was on the lift I asked the guy to kindly "break" the o2's for me. He happily obliged no charge. Got home, slid under there, and happily got rust in my eyes as I got each one out. Took 20m.
 
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NatesTJ

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Does anyone have any suggestions where to get a NTK 23151 in the UK?
All that seems to be available over here is the usual suspects such as Bosch.
Thanks
 

Boojadean

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I'm buying a 2000 4.0/auto and it doesn't have cats coming off of the exhaust manifolds. It has two oxygen sensors in the pipes, but the wires are cut off, and i can't find any plugs for them to plug into. There is a sensor just before and after the cat down below, would it be possible that they just put a couple old sensors in to plug the holes in the manifolds? There are no codes and the check engine light isn't on.

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reddvltj

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I'm buying a 2000 4.0/auto and it doesn't have cats coming off of the exhaust manifolds. It has two oxygen sensors in the pipes, but the wires are cut off, and i can't find any plugs for them to plug into. There is a sensor just before and after the cat down below, would it be possible that they just put a couple old sensors in to plug the holes in the manifolds? There are no codes and the check engine light isn't on.

View attachment 363886

2000 Fed Emissions TJs do not have the pre cats.

It could be that someone bought and installed a CA emissions manifold not knowing there was a difference.
 

Boojadean

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2000 Fed Emissions TJs do not have the pre cats.

It could be that someone bought and installed a CA emissions manifold not knowing there was a difference.

I'm thinking what happened is they may have replaced the manifold, but didn't have plugs for the oxygen sensor holes so just used old sensors. I wasn't aware that there weren't pre-cats on a 2000, but it makes sense.
 
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reddvltj

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I'm thinking what happened is they may have replaced the manifold, but didn't have plugs for the oxygen sensor holes so just used old sensors. I wasn't aware that there weren't pre-cats on a 2000, but it makes sense.

2000 was kind of a transition year. As usual California is the first to require higher emissions standards so any TJs sold in CA new had the newer '01and up 4 sensor system, the Fed emissions still ran the "99 and prior 2 sensor system.
2001 they all went to the 4 sensor system accept for export models, but that's a whole different can-o-worms.
 

Boojadean

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2000 was kind of a transition year. As usual California is the first to require higher emissions standards so any TJs sold in CA new had the newer '01and up 4 sensor system, the Fed emissions still ran the "99 and prior 2 sensor system.
2001 they all went to the 4 sensor system accept for export models, but that's a whole different can-o-worms.

Yeah, seems like it's kind of a "tweener". The VIN number reads partly like a 2000 as well as a 2001 too. According to the VIN decoder the 5th and 6th digit should be a Y1 for a Sport model on a 2000, but mine's shows A4, which it should be on a 2001. Build date says March 2000.
 
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reddvltj

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Yeah, seems like it's kind of a "tweener". The VIN number reads partly like a 2000 as well as a 2001 too. According to the VIN decoder the 5th and 6th digit should be a Y1 for a Sport model on a 2000, but mine's shows A4, which it should be on a 2001. Build date says March 2000.

I haven't found any other sensors fell victim to the "Is it the '01 or '99 version" but I haven't had to replace a them yet either. SO at least now you know its a 2000 Federal Emissions model.
 

reddvltj

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Shuttlesworth

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Since NGK has discontinued the 23151 for 1997-1999 4.0 Upstream sensor, has anyone found a good replacement for this? I can not find one in stock anywhere.

I just purchased a 23131 as eBay states its the same thing, but I will report back if there are any issues.
 

Mike Z

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Since NGK has discontinued the 23151 for 1997-1999 4.0 Upstream sensor, has anyone found a good replacement for this? I can not find one in stock anywhere.

I just purchased a 23131 as eBay states its the same thing, but I will report back if there are any issues.

Just bought this at NAPA. If you buy online and have it shipped to you, shipping is free and they give you 20% off. SHIP20 is the code.

Mike

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OXYGEN SENSOR
Part #: NGK 23151
Qty: 1
$59.99
$74.99 /each
- $15.00 SHIP20 Promo
Estimated Delivery: Thu, Oct 20