Novak Conversions Jeep Wrangler TJ engine mounts

Codes for all four O2 sensors coming up on my 2006 Rubicon

Northgeorgiarider

Northgeorgiarider

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Original poster
Joined
Sep 24, 2019
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26
Location
North Georgia
All four codes are coming up on my 2006 Rubicon
P0135
P0141
P0155
P0161
I've changed out the sensors with NTK sensors. I've sent the computer off to SIA Electronics and they reported the ECM is fine. Any ideas to get me going. The codes come on all at the same time.
 
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How old are your Cats? Those will plug up and throw codes for your 02s. Do you feel any loss of power lately?

Swapped my plugged cats for Walker cats and cleared all my codes.
 
I was getting random O2 sensor codes too, fortunately I talked to the previous owner (Gerald of Savvy) who said he had already changed all four sensors which didn't help. It turned out to be my pre-cats causing the codes. Replacing them stopped all the codes and I haven't had a check engine since which has been 7-8 years.
 
Jerry Bransford said:
I was getting random O2 sensor codes too, fortunately I talked to the previous owner (Gerald of Savvy) who said he had already changed all four sensors which didn't help. It turned out to be my pre-cats causing the codes. Replacing them stopped all the codes and I haven't had a check engine since which has been 7-8 years.
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What are pre cats? Are you saying I need to replace my cataLytic converters. I thought the code for catalytic problems was P0432.
 
Northgeorgiarider said:
What are pre cats? Are you saying I need to replace my cataLytic converters. I thought the code for catalytic problems was P0432.
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Yes.

Pre-cats are the two cats in your downpipes right under the intake manifold. There is also a third cat under the vehicle next to the transfer case.

There are codes for a bad catalytic convertor, but more often than not those codes (or at least not all of them) will not be displayed when the pre-cats are going bad, instead the O2 sensor codes (all four of them) will show.

It's a crap shoot, sometimes you get the bad cat codes, other times you don't.

What we are saying is that you need to replace your pre-cats. I posted a link to the replacement part in my post above.
 
Chris said:
Your cats are done for, I'd bet on it.

Same thing happened on my 2005 Rubicon and it was the cats.

Replaced them with a set of these (which also work on your 2006):

https://www.amazon.com/dp/B0031G6YT6/?tag=wranglerorg-20

That got rid of the issue. The cats plug up over time, especially on a 13+ year old vehicle.
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Hey Chris, Do you see any reason that the cats you have marked above wouldn't work in a 2001. On amazon it says it doesn't fit. I know on mine the rear cat bolts on and this one is welded on. thanks
 
sawmillman said:
Hey Chris, Do you see any reason that the cats you have marked above wouldn't work in a 2001. On amazon it says it doesn't fit. I know on mine the rear cat bolts on and this one is welded on. thanks
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I can’t see why they wouldn’t. The exhaust systems are the same from 2001 on up.
 
I used the flowmaster exhaust system and it worked great. Codes gone. I also installed a quiet muffler and a new tailpipe. I did not want loud. My exported Jeep only has one O2 sensor, but this sytem is made for US models. I used bung plugs. Well, I should say O2 sensor bung hole plugs. I don't want to be taken out of context.


https://www.amazon.com/gp/product/B01MUT0383/?tag=wranglerorg-20
 
I have this same issue with all 4x O2 sensors throwing the heater codes on my LJR. P0135, P0155, P0141 and P0161. I just got this Jeep. The previous owner just replaced the battery prior to selling to me. I replaced Bank 1 pre and post Cat O2 sensors but didn't change anything. I have chased the wiring from the O2 sensors back to the PCM with no issue. The resistance on the O2 sensor circuit is ~5 ohms (in spec). When checking voltage at the sensor, it appears low (>8V). Does this point to a PCM failure? or needing new Cats?

I am also having issues with the factory locker system. The computer will not register that the T-case is in 4wd. I have chased the T-case sensor switch and closed the circuit. I know the circuit is closed at the PCM. Seems like multiple issues with a potential root cause of the PCM. Thoughts?
 
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rdharms said:
I have this same issue with all 4x O2 sensors throwing the heater codes on my LJR. P0135, P0155, P0141 and P0161. I just got this Jeep. The previous owner just replaced the battery prior to selling to me. I replaced Bank 1 pre and post Cat O2 sensors but didn't change anything. I have chased the wiring from the O2 sensors back to the PCM with no issue. The resistance on the O2 sensor circuit is ~5 ohms (in spec). When checking voltage at the sensor, it appears low (>8V). Does this point to a PCM failure? or needing new Cats?

I am also having issues with the factory locker system. The computer will not register that the T-case is in 4wd. I have chased the T-case sensor switch and closed the circuit. I know the circuit is closed at the PCM. Seems like multiple issues with a potential root cause of the PCM. Thoughts?
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Welcome

O2 codes are usually telling you there's something wrong with the cats. The sensors are doing their job.

The 4WD switch is not a simple open/close circuit.
You should start a separate thread.
 
rdharms said:
I have this same issue with all 4x O2 sensors throwing the heater codes on my LJR. P0135, P0155, P0141 and P0161. I just got this Jeep. The previous owner just replaced the battery prior to selling to me. I replaced Bank 1 pre and post Cat O2 sensors but didn't change anything. I have chased the wiring from the O2 sensors back to the PCM with no issue. The resistance on the O2 sensor circuit is ~5 ohms (in spec). When checking voltage at the sensor, it appears low (>8V). Does this point to a PCM failure? or needing new Cats?

I am also having issues with the factory locker system. The computer will not register that the T-case is in 4wd. I have chased the T-case sensor switch and closed the circuit. I know the circuit is closed at the PCM. Seems like multiple issues with a potential root cause of the PCM. Thoughts?
Click to expand...

Please fill out your profile so we know more about your Jeep. The more we know the quicker we can diagnose the problem.
 
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Thanks for the replies. New to the group here and appreciate the feedback. This is a 2005 LJR. 138k miles.

I know very little about the maintenance history of this vehicle. I will go ahead and start a new thread with all the details. I listed the 4wd issue because my understanding is the PCM sends the 4wd switch closed signal via the CANbus to the ElectroMechanical Instrument Cluster (EMIC). I know the switch is closed at the PCM. So I have two issues with both having the potential root cause of the PCM.
 
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