Collector grade Jeep Wrangler TJs for sale

Getting my dad's TJ back on the road

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Navarone

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Original poster
Joined
May 19, 2026
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7
Location
SF Bay Area
Hey guys this is my first post here, and I just wanted to say hello to the forum, and get some guidance with my 2006 TJ with 2.4L engine.

I recently inherited my dad's Jeep and I am trying to get it back on the road. Mechanically, it's fine, but it sat for about two and a half years, and I am having an issue passing SMOG.

Here’s the situation so far:

  • 2006 TJ Wrangler
  • 2.4L 4-cylinder
  • 6-speed manual

There are no codes, but I have one incomplete readiness monitor (O2 HTR), which I cannot get to complete.
All other monitors have completed successfully. My scanner simply shows:

1 INC
O2 HTR

I’ve put roughly 400 miles trying to complete the check, including highway drives at steady 55–65 mph with gentle acceleration/deceleration as recommended by my SMOG shop.

Jeep starts fine, runs well with no driveability issues. Battery is fine.

So from what I've Googled, it looks like I have a bad upstream O2 sensor.I visually inspected it, and it seems fine to me, but I'm not a mechanic.

I have a Mopar part number: 56029049AA. I'm ready to order it, but I wanted to check here and see if I am missing anything, and to get as much education as I can. All thoughts and advice are appreciated.

Thanks in advance.
 
What voltages does the suspected bad O2 sensor range at? Without getting into too many details a "good" O2 sensor will range below .9v.

-Mac
 
I wish I could tell you, my scanner doesn't support live data. But even if the voltage check out, could the heater part still be bad? I have a friend with another scanner I can get my hands on later so I can check the voltage and post then
 
TheBoogieman said:
Only in Cali would you hear this statement. The most regulations, yet the worst of everything. :rolleyes:
Click to expand...

Well I live in a state that desperately wants to be CA east . The party in power , adopted CA's smog req's . This means if I had to replace a cat on my vehicles it would have to be a CARB approved cat . Even when all the vehicles were built to 49 state Federal standards . I can't even buy a 49 state cat through mail order . :rolleyes:
 
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macleanflood said:
Of course. Short of you and a handful of luddites, the Amish and Mennonites... it's a very safe assumption. =)

-Mac
Click to expand...

I love it when people call me a "luddite" as I've forgotten more about computers than most people will ever know. ;)

More serious question: I'm fixing on installing a pressure gauge on my fuel rail - I have the adapter, blah, blah, blah. I ASS-U-ME that I should pull the fuel pump fuse and run it until it stalls so I don't spray pressurized gas all over the place - or am I overthinking this?
 
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Zorba said:
I love it when people call me a "luddite" as I've forgotten more about computers than most people will ever know. ;)

More serious question: I'm fixing on installing a pressure gauge on my fuel rail - I have the adapter, blah, blah, blah. I ASS-U-ME that I should pull the fuel pump fuse and run it until it stalls so I don't spray pressurized gas all over the place - or am I overthinking this?
Click to expand...

That should work just fine . Also , only a small amount of fuel should spray out before the pressure drops to zero .
 
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Navarone said:
There are no codes, but I have one incomplete readiness monitor (O2 HTR), which I cannot get to complete.
All other monitors have completed successfully. My scanner simply shows:
Click to expand...

It's not going to complete if this TSB hasn't been done.
 

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Navarone said:
Hey guys this is my first post here, and I just wanted to say hello to the forum, and get some guidance with my 2006 TJ with 2.4L engine.

I recently inherited my dad's Jeep and I am trying to get it back on the road. Mechanically, it's fine, but it sat for about two and a half years, and I am having an issue passing SMOG.

Here’s the situation so far:

  • 2006 TJ Wrangler
  • 2.4L 4-cylinder
  • 6-speed manual

There are no codes, but I have one incomplete readiness monitor (O2 HTR), which I cannot get to complete.
All other monitors have completed successfully. My scanner simply shows:

1 INC
O2 HTR

I’ve put roughly 400 miles trying to complete the check, including highway drives at steady 55–65 mph with gentle acceleration/deceleration as recommended by my SMOG shop.

Jeep starts fine, runs well with no driveability issues. Battery is fine.

So from what I've Googled, it looks like I have a bad upstream O2 sensor.I visually inspected it, and it seems fine to me, but I'm not a mechanic.

I have a Mopar part number: 56029049AA. I'm ready to order it, but I wanted to check here and see if I am missing anything, and to get as much education as I can. All thoughts and advice are appreciated.

Thanks in advance.
Click to expand...

If it’s just an O2 sensor get after it. $30 and done. Get NTK/NGK sensor. Nothing else.
 
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Navarone said:
Hey guys this is my first post here, and I just wanted to say hello to the forum, and get some guidance with my 2006 TJ with 2.4L engine.

I recently inherited my dad's Jeep and I am trying to get it back on the road. Mechanically, it's fine, but it sat for about two and a half years, and I am having an issue passing SMOG.

Here’s the situation so far:

  • 2006 TJ Wrangler
  • 2.4L 4-cylinder
  • 6-speed manual

There are no codes, but I have one incomplete readiness monitor (O2 HTR), which I cannot get to complete.
All other monitors have completed successfully. My scanner simply shows:

1 INC
O2 HTR

I’ve put roughly 400 miles trying to complete the check, including highway drives at steady 55–65 mph with gentle acceleration/deceleration as recommended by my SMOG shop.

Jeep starts fine, runs well with no driveability issues. Battery is fine.

So from what I've Googled, it looks like I have a bad upstream O2 sensor.I visually inspected it, and it seems fine to me, but I'm not a mechanic.

I have a Mopar part number: 56029049AA. I'm ready to order it, but I wanted to check here and see if I am missing anything, and to get as much education as I can. All thoughts and advice are appreciated.

Thanks in advance.
Click to expand...

The TSB 25-005-13 Rev.A mentioned above by @JKP and @Steel City 06 is worth knowing about even if it doesn't fix your issue. That said, the TSB fix solved my readiness issue.

Many go with the NTK sensor that @JMT mentioned since the cost is generally lower than the Mopar o2 sensor (that NTK manufactured for Mopar).
 
Last edited:
MikeE024 said:
The TSB 25-005-13 Rev.A mentioned above by @JKP and @Steel City 06 is worth knowing about even if it doesn't fix your issue. That said, the TSB fix solved my readiness issue.

Many go with the NTK sensor that @JMT mentioned since the cost is generally lower than the Mopar o2 sensor (that NTK manufactured for Mopar).
Click to expand...

Didn't mean to resurrect an old thread but I came across some info that might help other people dealing with the same thing.

I came across that TSB too, and from what I understand, Jeep will do it free of charge if you want to take care of it.

I also found this: https://www.bar.ca.gov/obd-test-reference

It's a diagnostic test reference from the California Bureau of Automotive Repair (BAR), which is an agency I've never heard of before, but it's a legit state agency and it has a list of cars that have exemptions for certain known, SMOG diagnostic faults.

2005-2006 Wrangler is on that list.

This is how I got it to pass SMOG, I just mentioned this list. Had to go to two places, because the first place had no idea what I was talking about.
 
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I had an issue with that same thing, i bought a pr of "cheaters" they extended the downstream plugs out. I forget what they're technically called.
https://postimg.cc/3drv51wT
 

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