The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

Can bad O2 sensors cause a bus communication error and then complete shut down of the engine?

My Jeep runs for a few minutes, then stumbles & quits running. When it does, all the warning dash lights come on, the gauges read zero, and my code scanner reports a link error. I often get several codes reporting such at throttle position sensor, crankshaft & camshaft sensors, idle air control, misfire, & bus failure communication errors. But I keep getting all four O2 sensors after clearing all the codes.

I have a 2005 Jeep Wrangler Rubicon with a 4.0 & manual trans. It has 90k miles on it and I replaced the upper two O2 sensors five years ago (with the correct NGK/NTK brand sensors) and I have put about 10k miles on it in the last five years.

I am leaning towards a bad PCM, but the repetitive O2 sensor codes is making me wonder if it could be the O2 sensors? I don't know if I should replace the PCM at the cost of $400 or place a $100 bet on four O2 sensors?

Thanks, Shimaze

O2 - 01.jpeg


O2 - 02.jpeg
 
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Update - I replaced both the crank & cam sensors

I still get all four O2 sensors reporting as bad. Specifically, I get P0031, 37, 51, & 57. This is the heater circuit low for all four O2 sensors. Is there a fuse somewhere or something else that would prevent the O2s from heating up? I could see one or two O2s being defective and failing to heat. But something else is else causing all four not to heat up. I get these codes soon after the engine starts.

Any ideas?
 
I did the TSB 25-001-07 modification in hopes that it would cure the problem with the O2 sensors. Needless to say this did NOT help the problem with the O2 sensors not heating up. In fact, this modification seemed to make the problem worse! It goes into communication failure almost immediately. It still gives the four trouble codes previously mentioned.

Is there a fuse I need to look for that goes to the heating elements on the O2s? Why does the gauges on the dash go out and the key light come on? What is the purpose of wack mode? I have a same year Scion xB that has 290k miles and it has problems with the O2s most likely because it smokes like a freight train. Yet it keeps running and has no wack mode and associated automatic shut down relay.

I am hesitant about having the PCM repaired and / or replacing the O2s. If I knew of a way to ditch all of the electronic crap and install a reliable distributor and carburetor I would do that. With all the problems related to sensors, computers. wack mode and ASD, a carburetor & distributor may be the only long term viable solution?

For any one wanting to do the TSB 25-001-07 mod, the best source of information can be found at:

http://future.obdclearinghouse.com/documents/newdocuments/tsb/jeep/25-001-07.pdf
 
shimaze said:
I did the TSB 25-001-07 modification in hopes that it would cure the problem with the O2 sensors. Needless to say this did NOT help the problem with the O2 sensors not heating up. In fact, this modification seemed to make the problem worse! It goes into communication failure almost immediately. It still gives the four trouble codes previously mentioned.

Is there a fuse I need to look for that goes to the heating elements on the O2s? Why does the gauges on the dash go out and the key light come on? What is the purpose of wack mode? I have a same year Scion xB that has 290k miles and it has problems with the O2s most likely because it smokes like a freight train. Yet it keeps running and has no wack mode and associated automatic shut down relay.

I am hesitant about having the PCM repaired and / or replacing the O2s. If I knew of a way to ditch all of the electronic crap and install a reliable distributor and carburetor I would do that. With all the problems related to sensors, computers. wack mode and ASD, a carburetor & distributor may be the only long term viable solution?

For any one wanting to do the TSB 25-001-07 mod, the best source of information can be found at:

http://future.obdclearinghouse.com/documents/newdocuments/tsb/jeep/25-001-07.pdf
Click to expand...



Shimaze,

I read on another forum of someone who was having almost exactly the same issues you are, and he had posted a picture of the problem. He had the 4.0l engine, and where the wiring harness came around the firewall end of the engine, one of the bolts sticking up from the engine had worn through the wiring loom and into one of the wires inside the loom. As I write this, it may have been that I saw it on a YouTube video.
He found it by starting the engine and then grabbing various wire looms and tugging around on them. He did this after confirming there was no corrosion inside the PCM connectors. But when he tugged the loom going behind the engine, it shorted that worn wire to ground and killed the engine - including sending all the dash gauges to a "dead" state.

Sorry to all for hijacking the thread, and hope that it can get back on track.
 
Chris said:
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



​
6 Cylinder Engines​
​
1997-1999​
NGK #23151 - 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)​
Click to expand...

please confirm: in the above drawing which way is the front of the jeep. I had assumed the front was the left side of the drawing. I'm in the middle of replacing the two upstream sensors for 6-cylinder 2000 Sahara. I have the NGK 23122 and NGK 23506. I thought the 23122 was for the front sensor (Bank 1) but the wires for the two sensors are different lengths. it appears they are only long enough if I switch them. this may be my answer but I'd appreciate independent confirmation.
 
JC123 said:
please confirm: in the above drawing which way is the front of the jeep. I had assumed the front was the left side of the drawing. I'm in the middle of replacing the two upstream sensors for 6-cylinder 2000 Sahara. I have the NGK 23122 and NGK 23506. I thought the 23122 was for the front sensor (Bank 1) but the wires for the two sensors are different lengths. it appears they are only long enough if I switch them. this may be my answer but I'd appreciate independent confirmation.
Click to expand...

Bank 1 is nearest the front of the Jeep, Bank 2 is behind it.

You can check the official NGK website as it has all of the part numbers and locations on the site. I pulled these part numbers directly from the NGK official website. It’s possible I made an error, so double check their website and confirm.
 
Thanks Chris.
I confirmed on the NGK website that you have it right. I submitted a question through the NGK website. we'll see what they say. I installed the 23506 sensor without issue. For now, I left the existing Bank 1, Sensor 1 (front, upstream) sensor in place.
To illustrate the issue, here's a photo of the 23122 and 23506 sensors next to the existing ones I'm trying to replace. I
probably need another 6"-8" of wire to make the 23122 to work.

oxygen sensors.JPG
 
JC123 said:
Thanks Chris.
I confirmed on the NGK website that you have it right. I submitted a question through the NGK website. we'll see what they say. I installed the 23506 sensor without issue. For now, I left the existing Bank 1, Sensor 1 (front, upstream) sensor in place.
To illustrate the issue, here's a photo of the 23122 and 23506 sensors next to the existing ones I'm trying to replace. I
probably need another 6"-8" of wire to make the 23122 to work.
Click to expand...
Where did you buy them? I'm wondering if someone, at sometime, got them mixed up at into the wrong boxes. Were they sealed when got them?
 
Code P0157, Voltage Low. Took my jeep into the shop and it was throwing the P0157. Changed all 4 spark plugs (only needed Bank2 Sensor2) using the recommended parts and followed the instructions on the first page. Couldn't of been easier, thank you for the original post. 2006 Sport, 47,000 miles.
 
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@dbbd1, I wondered the same thing. I purchased them through Amazon from a company called Sixity Auto and they were sealed.

update: I spoke to a service rep at NGK/NTK. He clarified that 23122 is for engines that comply with federal emission standards. Those engines apparently have only two sensors (one upstream and one downstream). Since mine has four sensors (two upstream and two downstream) that tells him that mine complies with California emissions. He confirmed that 23506 is the correct upstream rear sensor (Bank 2, Sensor 1) but told me that 23099 is the matching sensor for Bank 1, Sensor 1 (upstream, front). 23122 (the one I purchased) is 10" long (measured from the gasket) and 23099 is 18" long which is about what I thought I needed to reach the connector. I'll provide an update when the new sensor shows up and hopefully be able to report that it went in without difficulty.
 
update: went to install the NTK 23099 oxygen sensor today and, though the length is right, the wiring connector doesn't match up. In the photo below, the old sensor is on the right and the 23099 is on the left. The nubbin on top is at the 12 o'clock position on the old one but it's at the 1 o'clock position on the new sensor. NTK customer service is closed on the weekends so I'll call them monday and hopefully figure out which sensor I need.
0xygen sensor 23099.JPG
 
JC123 I have the California dual cat and I had ordered the 23122 and noticed there is no way that will reach with it being so short. With that being said what is the right now for the California dual cat?
 
atlantatjowner said:
Problem is that the site says its the 23122 but no way is that long enough. Its maybe 7" long at most
Click to expand...

That doesn't make any sense then. It sounds like you'll either have to extend the wires, or NGK has the wrong part number in their system.
 
atlantatjowner said:
JC123 I have the California dual cat and I had ordered the 23122 and noticed there is no way that will reach with it being so short. With that being said what is the right now for the California dual cat?
Click to expand...

atlantatjowner- what year is your jeep?
after much discussion with NGK rep and cross referencing the part number on the existing sensor I ordered 23151 which is indicated for the 1999 model year. I just checked the sticker on the door frame and saw that my jeep was mfg'd. in June of 2000, apparently before the model year change (though a search of the VIN number describes it as a 2000).
it's to arrive tomorrow and I'm hopeful this is the right one. I'll report back but you might need to use a sensor indicated for model year prior or following if yours was mfg'd. near the beginning or end of the model year.
good luck.
 
OK so I just contacted them and they only list the federal on their site and not the California for some reason. So the right one for NTK Bank 1 Sensor 1 on th California is 23099.




[/QUOTE]
atlantatjowner said:
They must have the wrong one listed because I just looked on Amazon where I purchased and product dimensions are 2x2x6

Click to expand...
 
one more thing: before ordering 23151 I tried 23506. NGK told me it is indicated for California emissions and is 14" long but the wiring connector didn't match up as shown in the photo I posted previously. that one could work for you, depending on your model year.
 
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