Are my O2 sensors bad?

[bornhunter]

Finally after a 2 year search for the right one, I pulled the trigger yesterday on a nice 06 unlimited LJ.

So I test drive it, no engine light. 2 days later I pick it up and drive it home 100+ miles, no engine light. I start it up this morning, engine light on. Oreillys checked it for me and said 02 sensor. The seller told me he just replaced the 02 sensors because the light came on a few weeks ago. O'Reilly guy sensors did look new. Code is P 0152. Any ideas?

 

[jchadscud]

If it wasn’t replaced with a NGK/NTK brand Sensor that could be your issue. Check out this thread:

The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

 

[bornhunter]

Hey thanks. I will get with the seller and see what he put in.

 

[jchadscud]

Congrats on the new purchase! There’s a ton of good people and info on this forum. Post some pics of the new addition!

 

[bornhunter]

Thats great. I just got it yesterday so no pics just yet. I am going to put a slight lift and add some nice tire and wheels and I will snap some pics. That causes me to ask more q's. With a 2 inch spacer lift, can I go 32's with no issues. And should I add a teack bar with a 2 inch?

 

[Jerry Bransford]

My 04 TJ's O2 repeated intermittent sensor codes were caused by a bad pre-catalytic converter. Still running the original O2 sensors with the new catalytic converters. No O2 codes in the 4-5 years since it got the new catalytic converters.

 

[KCsTJ]

Finally after a 2 year search for the right one, I pulled the trigger yesterday on a nice 06 unlimited LJ.

So I test drive it, no engine light. 2 days later I pick it up and drive it home 100+ miles, no engine light. I start it up this morning, engine light on. Oreillys checked it for me and said 02 sensor. The seller told me he just replaced the 02 sensors because the light came on a few weeks ago. O'Reilly guy sensors did look new. Code is P 0152. Any ideas?

Same thing happened to me.

The seller resets the obdii engine codes right before you pick it up so you get 50 miles of no codes then reality hits when codes start to appear.
That's a common tactic and i half expected it when i bought mine. :-/

 

[Jerry Bransford]

Same thing happened to me.

The seller resets the obdii engine codes right before you pick it up so you get 50 miles of no codes then reality hits when codes start to appear.
That's a common tactic and i half expected it when i bought mine. :-/

I never thought about it but 50 miles is about how far I made it after buying my TJ and got the first O2 sensor codes and CEL.

 

[pagrey]

Cats are bad, seller fooled you. Sorry.

 

[Chris]

If it wasn’t replaced with a NGK/NTK brand Sensor that could be your issue. Check out this thread:

The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

X2 to this.

Check out this thread as mentioned:
The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

 

[bornhunter]

Shame on people who do that stuff. Interesting thing is the seller replaced the 02 sensors? The guy who checked it for me said he could tell the sensors are new. Oh well. So whats involved with replacing the cats. Will engine light reset once replaced?

 

[JMT]

Shame on people who do that stuff. Interesting thing is the seller replaced the 02 sensors? The guy who checked it for me said he could tell the sensors are new. Oh well. So whats involved with replacing the cats. Will engine light reset once replaced?

You can reset it by just disconnecting the battery.
I’d try the right o2 sensors first

 

[bornhunter]

I will start there. Thank you.

 

[Jamison C]

I agree with the suggestion to start at the sensors. Whether the cats are bad or not, if the new sensors aren’t Mopar or NGK it’ll likely throw codes.

 

[bornhunter]

Ok thanks. Are there 2 or 4 02 sensors?

 

[Jerry Bransford]

Ok thanks. Are there 2 or 4 02 sensors?

There are four on your newer 4.0 TJ, two on early 2000 and older 4.0 engines.

 

[Hcwlsu101]

How many miles are on the Jeep? If they are original, it’s probably time to change the cats anyway.

 

[KCsTJ]

How many miles are on the Jeep? If they are original, it’s probably time to change the cats anyway.

I've noticed a pattern in my one whole year experience of being a jeep head..... when the 4.0L gets close to 100k the precats are done.

The 02 sensor codes show up first... when the 02 sensors are replaced and the same codes come back that means pre cats are toast and must be replaced.

 

[ZEN357]

I hope you don;t have to replace the cats, those are expensive!!! $$$

 

[KCsTJ]

I hope you don;t have to replace the cats, those are expensive!!! $$$

Yep $300