Oxygen Sensor assistance - Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today

Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 08-06-2013, 09:53 AM
Thread Starter
Join Date: Jun 2013
Posts: 63
twmattox is on a distinguished road
Oxygen Sensor assistance

2005 LJ, 4.0

Well, at around 106k miles I got my first check engine light P0153 code. Figured I would replace all 4 oxygen sensors. The only ones in stock were Bosch. Well, about 2-days later same code popped up. Replaced a couple of the sensors twice same code. Performed the TSB 25-001-07 rewire and same code.

So, I bought new NKT sensors. All seemed fine for a day. Now, same stupid code.

So, looks like my issue is NOT the sensors. I recently had the rig into the muffler shop for a leaky muffler. May have an exhaust leak. I know on my wife's old Grand Cherokee with a 4.0 that the exhaust manifolds had an issue with cracking. Does the 2005 4.0 have the same issue? Where would you start looking for an exhaust leak?

I assume that if this is not the case, I look at electrical. Thoughts on where to start?

'83 Scrambler (CJ-8) / 258 / T-5 / D-300 / DANA 30-AMC20 (3.31)
'88 Grand Wagoneer (SJ) / 360 / TF727 / NP229 / DANA 44 (2.73)
'05 Wrangler Unlimited (LJ) / 4.0L / NSG 370 / NV231 / DANA 30-44 (3.73)
'15 Wrangler Unlimited (JKU) / 3.6L / 42 RLE / NV 241 / DANA 30-44 (3.73)
twmattox is offline   Quote
Old 08-06-2013, 10:34 PM   #2
ChasUGC's Avatar
Join Date: Jul 2013
Posts: 2,974
ChasUGC is on a distinguished road
Start with the cat. O2 sensors are above the cat. Most people seem to think that it means the O2 sensor is malfunctioning. Even the dealership changed mine. I came to find out that the O2 sensor was working as it should and it informed me of the problem with my cat. The cat is much more sensitive than the O2 sensor because it is made of ceramic(I.E. glass) inside. If the cat is going bad, you will know in time. Eventually it will break down completely and you will hear lots of broken glass sounds inside it when you tap or shake it. Your performance will suffer, you might get stalling, difficulty switching gears, improper high revs, and I've heard that engine fires have happened(Backfiring), from the clogged exhaust system. Tap, or shake the cat and see if you hear broken glass like sounds inside it. My guess is that your cat is going bad, and your O2 sensor is giving you fore warning. I imagine this is common in vehicles like Jeeps which take a lot of jostling in off road excursions.

ChasUGC is offline   Quote
Old 08-07-2013, 02:27 PM
Thread Starter
Join Date: Jun 2013
Posts: 63
twmattox is on a distinguished road
I am really hoping it is an exhaust leak. I have a slight tap coming from the driver side engine bay. Only happens under load (not while parking).

This weekend I will put my shop vac hose (connected to the exhaust side) into my tail pipe and hit the whole thing with soapy water. IF I am lucky it will be a simple fix...I hope...
'83 Scrambler (CJ-8) / 258 / T-5 / D-300 / DANA 30-AMC20 (3.31)
'88 Grand Wagoneer (SJ) / 360 / TF727 / NP229 / DANA 44 (2.73)
'05 Wrangler Unlimited (LJ) / 4.0L / NSG 370 / NV231 / DANA 30-44 (3.73)
'15 Wrangler Unlimited (JKU) / 3.6L / 42 RLE / NV 241 / DANA 30-44 (3.73)
twmattox is offline   Quote
Old 08-07-2013, 02:33 PM   #4
Commercial Member

5-Year WF Supporting Member
Big Sarge's Avatar
Join Date: Dec 2012
Location: Fort Drum NY
Posts: 5,790
Big Sarge is on a distinguished road
yes the 4.0s are prone to having cracked manifolds, could very well be the issue.


/l ,[____],
l---L -OlllllllO-
()_) ()_)--o-)_)
Big Sarge is offline   Quote
Old 08-07-2013, 07:40 PM   #5
Shelby427's Avatar
Join Date: May 2011
Location: Lakeland FL and Hooversville PA
Posts: 2,379
Shelby427 is on a distinguished road
Yeah not always an O2 sensor when you have that code. Gets folks into trouble as they think it's the sensor, when in fact it can be quite a few things that will set the code.

Like mentioned, an exhaust leak can set it, bad wiring to the sensor, inlet air leak, even a faulty MAF sensor can cause it. And yes even a faulty O2 sensor.

But what I'm getting at, don't jump the gun and throw parts at a problem. Can get expensive if you guess wrong. There is a diagnostic flow chart for each code, follow it and it will lead you to the correct fix. Could be something as simple as a loose fitting ahead of the MAF. Replacing the O2 sensors isn't going to correct that.

The code tells you what part of the system is acting up, in this case it's telling you that the fuel mixture is not being adjusted properly or at a normal amount of times when the engine is in closed loop.
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.
Shelby427 is offline   Quote
Old 08-07-2013, 08:06 PM   #6
Join Date: Mar 2010
Location: Warner Robins, GA
Posts: 756
jkp is on a distinguished road
The exhaust flange bolts on the converters are known to loosen.

The code indicates that the sensor response is slow. Causes could be the wiring, exhaust leak, O2 sensor.
'92 Islander
'06 Rubicon
jkp is offline   Quote
Old 08-07-2013, 08:14 PM   #7
I am JD and it's My Dream

WF Supporting Member
::WF Administrator::
JDsDream's Avatar
Join Date: Jan 2009
Location: The Peach State
Posts: 29,262
JDsDream is on a distinguished road
I had the same issue and the same code with my 06 LJ. Replaced the manifold gasket and that took care of it.
The kind of woman that when my feet hit the floor each morning the devil says "Oh Crap, She's up!"

To All Of Our Forum Veterans and Active Service Members.
Our Debt To You Is Greater Than We Could Ever Repay.
Thank You


Become a Supporting Member!
JDsDream is offline   Quote
Old 09-05-2013, 10:48 PM   #8
Join Date: Mar 2012
Location: Cleveland Heights, OH
Posts: 1
ngostout is on a distinguished road
Send a message via Skype™ to ngostout
I have pretty much the same problem only on my 03 and I get the rough starts occasionally though. Glad I found this thread. I like the idea of the shop vac reverse, and soapy water to look for a leak. Will a gasket leak show up with this method too? I also wasted cash replacing sensors. (Also had a mechanic say it was a vacuum leak and want to charge me >1k to repair it.)

ngostout is offline   Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 12:27 AM.

User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC
« Back

Enter your email address:

Delivered by FeedBurner