Which 02 sensor? - Jeep Wrangler Forum
Jeep Wrangler Forum

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

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 01-24-2008, 03:58 PM   #1
Jeeper
 
Boulderv7's Avatar
 
Join Date: Nov 2006
Location: Grand Rapids MI
Posts: 127
Which 02 sensor?

My jeep is throwing code p0138 (Oxygen sensor input voltage maintained above normal operating range.) Does this mean my 02 sensor is bad? and if i'm correct, there are two of them, one on the manifold and one after the cat, correct? How do i know which one to replace? Should i just replace them both? Little jerks are kinda pricey for how small they are...

__________________
Boulderv7

.....01 TJ 4 banger, 2 in lift, 32x11.5 on 15x10 black steelies.....
Boulderv7 is offline   Quote Quick Reply
Old 01-24-2008, 05:57 PM   #2
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 29,190
Images: 2
The rear (downstream) 02 sensor monitors the catalytic converter for proper operation. It's the front 02 sensor that affects how well the engine runs and its mpg by monitoring the air-fuel mixture. When the front (upstream) 02 sensor goes bad, it signals the engine computer that the engine is running too lean so the computer sets the air-fuel mixture to full rich which reduces mpg and performance. It's the front 02 sensor that goes bad more often and when it goes bad, it causes performance/mpg problems.

A bad rear/downstream 02 sensor would only falsely claim the catalytic converter is not performing properly.

P0138 technically decodes to Bank 1 Sensor 2 which means it's the downstream sensor which would indicate the 02 sensor on the catalytic converter. That's the one I'd swap first. Or perhaps the cat is going bad...

__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 01-24-2008, 09:07 PM   #3
Jeeper
 
Boulderv7's Avatar
 
Join Date: Nov 2006
Location: Grand Rapids MI
Posts: 127
yeah, i haven't noticed any performance problems, or bad mileage, so i'll replace the downstream sensor... if it keeps throwing the code after that, its probably my cat, huh? That'll be a good excuse to buy a high flow cat.... well, thanks alot for the info, WF comes through once again!!!!
__________________
Boulderv7

.....01 TJ 4 banger, 2 in lift, 32x11.5 on 15x10 black steelies.....
Boulderv7 is offline   Quote Quick Reply
Old 01-25-2008, 09:38 AM   #4
Jeeper
 
TXST8tj's Avatar
 
Join Date: Jan 2007
Location: Katy, TX
Posts: 1,780
Send a message via AIM to TXST8tj
not sure what the upstream sensor runs, but i just bought a bosch downstream for $90. expensive little buggers.
__________________
- Patrick
TXST8tj is offline   Quote Quick Reply
Old 01-25-2008, 04:06 PM   #5
Jeeper
 
Boulderv7's Avatar
 
Join Date: Nov 2006
Location: Grand Rapids MI
Posts: 127
yeah, pretty damn ridiculous.... what are they made of gold, platinum, and puppy dog hearts or what!?!
__________________
Boulderv7

.....01 TJ 4 banger, 2 in lift, 32x11.5 on 15x10 black steelies.....
Boulderv7 is offline   Quote Quick Reply
Old 01-25-2008, 04:58 PM   #6
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 29,190
Images: 2
Quote:
Originally Posted by Boulderv7 View Post
yeah, pretty damn ridiculous.... what are they made of gold, platinum, and puppy dog hearts or what!?!
Exactly, they have some expensive stuff inside like platinum and zirconium inside. Same reason thieves are making a good living stealing and selling catalytic converters.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 01-25-2008, 05:01 PM   #7
Jeeper
 
Join Date: Nov 2006
Location: Chicago, IL
Posts: 8,286
Send a message via AIM to Triple88a Send a message via MSN to Triple88a Send a message via Yahoo to Triple88a Send a message via Skype™ to Triple88a
Jerry whats in a cat? jw
Triple88a is offline   Quote Quick Reply
Old 01-25-2008, 05:07 PM   #8
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 29,190
Images: 2
Quote:
Originally Posted by Triple88a View Post
Jerry whats in a cat? jw
Platinum, rhodium and/or palladium. That stuff is seriously expensive, they're even toying with using gold which is cheaper yet works even better.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote Quick Reply
Old 01-25-2008, 07:05 PM   #9
Jeeper
 
Boulderv7's Avatar
 
Join Date: Nov 2006
Location: Grand Rapids MI
Posts: 127
damn, jerry's a smart guy.... so if i replace my cat can i dissasemble and melt down my old one, sell the metals and get some cash back or what? that'd be nice....
__________________
Boulderv7

.....01 TJ 4 banger, 2 in lift, 32x11.5 on 15x10 black steelies.....
Boulderv7 is offline   Quote Quick Reply
Old 01-25-2008, 07:42 PM   #10
Jeeper
 
Join Date: Nov 2006
Location: Chicago, IL
Posts: 8,286
Send a message via AIM to Triple88a Send a message via MSN to Triple88a Send a message via Yahoo to Triple88a Send a message via Skype™ to Triple88a
Quote:
Originally Posted by Boulderv7 View Post
damn, jerry's a smart guy.... so if i replace my cat can i dissasemble and melt down my old one, sell the metals and get some cash back or what? that'd be nice....
Isnt an old dirty cat filled with toxic gases and such things?

Triple88a is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
O2 sensor problem solved! dr_donahue TJ General Discussion Forum 73 09-26-2013 03:11 PM
Sensor Info Needed JDsDream TJ Tech Forum 1 01-07-2009 11:36 AM
02 Sensor Heater Circuit (Bank 2 Sensor 2) cork1958 TJ General Discussion Forum 0 11-09-2008 09:56 PM
97 TJ O2 sensor problem HarryJeeper61 TJ Tech Forum 2 11-30-2007 05:29 AM
Oxygen Sensor OBD Code - How to fix?? AggieChris TJ Tech Forum 15 06-14-2006 11:05 AM



» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 04:05 AM.



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