Engine light! - 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 06-17-2014, 11:59 PM
Thread Starter
  #1
Jeeper
 
Join Date: Dec 2012
Location: Green Bay, WI
Posts: 331
Engine light!

On and off, the engine light came on over the past months. Then it goes away. There seems to be no problem. The engine runs fine. But now it is on and stays on, and again everything runs fine.

Does anyone really think there is a problem with my engine, or is it just the computer. If it is just the computer, does anybody have a suggest of how to get that light to shut off.

Thanks.

Joe

Hazlitt777 is offline   Quote
Old 06-18-2014, 12:08 AM   #2
Jeeper
 
Join Date: Apr 2014
Location: Lake Murray, South Carolina
Posts: 2,173
You need to have the codes read!

Lakeman1 is offline   Quote
Old 06-18-2014, 01:20 AM
Thread Starter
  #3
Jeeper
 
Join Date: Dec 2012
Location: Green Bay, WI
Posts: 331
Okay. And then they reset it? In my manual it says it is either the engine, emissions or the automatic transmission. Well, it isn't the automatic because I have a manual. I bet it is emissions.
Hazlitt777 is offline   Quote
Sponsored Links
Advertisement
 
Old 06-18-2014, 01:47 PM
Thread Starter
  #4
Jeeper
 
Join Date: Dec 2012
Location: Green Bay, WI
Posts: 331
I had it checked. They say the the down stream o2 sensor is "shorted to voltage." I believe they want to replace both the down stream and up stream sensors. Parts and labor are $368.

The jeep runs fine and I just checked my gas mileage after driving mostly highway and some in town: 18.7 mpg!

So it runs fine. Why should I replace it while my fuel mileage is still good?

Tell me why I may be wrong or why I may be right?
Hazlitt777 is offline   Quote
Old 06-18-2014, 03:06 PM   #5
Jeeper
 
Roy626's Avatar
 
Join Date: Apr 2014
Location: Limestone
Posts: 703
Quote:
Originally Posted by Hazlitt777 View Post
I had it checked. They say the the down stream o2 sensor is "shorted to voltage." I believe they want to replace both the down stream and up stream sensors. Parts and labor are $368.

The jeep runs fine and I just checked my gas mileage after driving mostly highway and some in town: 18.7 mpg!

So it runs fine. Why should I replace it while my fuel mileage is still good?

Tell me why I may be wrong or why I may be right?
1) Depending on where you live if there is a vehicle emissions inspection you will NOT pass with a CEL on.

2) The CEL is letting you know something is wrong. (in this case O2 sensor) While your jeep may be running fine now it might not keep running fine and will most likely occur when you need it the most.(Murphy's Law)

If you are mechanical change them yourself and save the labor $$
__________________
Roy

My Build Thread:
https://www.wranglerforum.com/f322/97...on-720946.html
Roy626 is offline   Quote
Old 06-18-2014, 04:36 PM   #6
Jeeper
 
Join Date: Jun 2014
Location: Imperial Valley.... California's butthole!
Posts: 18
Most o2 sensors can be swapped out without hardly any mechanical background... It should be easy for you! May I suggest staying with oem sensors. Anything aftermarket, doesn't matter what vehicle, will just fail in a short amount of time.
Duncanhi9 is offline   Quote
Old 06-18-2014, 05:29 PM
Thread Starter
  #7
Jeeper
 
Join Date: Dec 2012
Location: Green Bay, WI
Posts: 331
Thanks guys. My dad and I will be able to do this. He even has the tool to reset the engine sensor light. It will sure be a lot cheaper.
Hazlitt777 is offline   Quote
Old 06-19-2014, 07:14 PM   #8
Jeeper
 
Join Date: Oct 2013
Location: Ontario, CDA
Posts: 18
Engine Light

Quote:
Originally Posted by Hazlitt777 View Post
Okay. And then they reset it? In my manual it says it is either the engine, emissions or the automatic transmission. Well, it isn't the automatic because I have a manual. I bet it is emissions.
Can I ask what year your jeep is? Mine is 2014 and the engine light just came on for no reason today. I was driving into a plaza and it lit up as well as the traction control light, but that one went out. Called dealership to make appt as still under warranty. Pending the visit on Tuesday to see what they say.
KarneyB is offline   Quote
Old 06-20-2014, 10:02 PM
Thread Starter
  #9
Jeeper
 
Join Date: Dec 2012
Location: Green Bay, WI
Posts: 331
Mine is a 1999. It cost me $63 dollars to have a Jeep dealership check it and determine what was wrong. It turned up to be the O2 sensor.

If you have a friend with the right equipment, they can check it for you and save you a bit.
Hazlitt777 is offline   Quote
Old 06-21-2014, 11:08 AM   #10
Jeeper
 
Neil F.'s Avatar
 
Join Date: Nov 2007
Location: Marlton, NJ
Posts: 6,886
Quote:
Originally Posted by Hazlitt777 View Post
Mine is a 1999. It cost me $63 dollars to have a Jeep dealership check it and determine what was wrong. It turned up to be the O2 sensor.

If you have a friend with the right equipment, they can check it for you and save you a bit.
Unfortunately 99 cannot read it on the odometer (other years can) but many places, Autozone, AAMCO, Midas will read codes for free
__________________
2003 TJ, 33" BFG AT, 2" BL, 2" BDS spring lift, Truck Lite headlights, Homemade sunrider top.
Neil F. is offline   Quote
Old 06-21-2014, 02:19 PM   #11
Jeeper
 
Join Date: Apr 2014
Posts: 88
Never go to a shop to get the codes read.
Most auto parts places will read for free.

Its a $10 socket (tool)

Replace the o2 sensor that's after the cat.

I had a random p0420 code on my 2004 LJ.

Ran great. Avg mpg
I did the anti-fouler trick and no more issues with cel.
Old Man Hatch is offline   Quote
Old 07-02-2014, 05:17 PM
Thread Starter
  #12
Jeeper
 
Join Date: Dec 2012
Location: Green Bay, WI
Posts: 331
What is the "anti-fouler trick?"
Hazlitt777 is offline   Quote
Old 07-02-2014, 07:44 PM   #13
Jeeper
 
Join Date: Apr 2013
Posts: 13,017
The o2 sensor on tj is old school voltage generating o2 sensor

Typically 3 wires one is a key controlled plus 12 volts to power a heater element inside the sensor
Then a ground wire
Finally the sensor signal wire
When good and hot the sensor itself generates a small voltage based on the difference in oxygen concentration of air outside and exhaust flowing past the tip of the sensor
Higher difference makes for more voltage but always small like under 2 volts

You can actually test a sensor with a propane torch and a voltmeter

If as you say the fault is sensor shorting to voltage look at harness of wires going to the sensor as that would mean friction or heat damaged insulation and metal inside of wire supplying power to sensor heater is touching metal inside wire that gets sensor signal

Find it and fix it might not cost you anything but some electrical tape
Digger84 is offline   Quote
Old 08-13-2014, 10:05 PM
Thread Starter
  #14
Jeeper
 
Join Date: Dec 2012
Location: Green Bay, WI
Posts: 331
Well, I replaced the sensor...but I had to Jerry rig it. I ordered the right one...for the 1999 with the 4.0. But the plug did not mate up perfectly. The plastic plug didn't line up correctly...the four wires did...but a plastic clip was wrong. So I cut if off and plugged it in. The sensor light went off. I hope I didn't do something wrong.
Hazlitt777 is offline   Quote
Old 08-14-2014, 06:02 AM   #15
Jeeper
 
Neil F.'s Avatar
 
Join Date: Nov 2007
Location: Marlton, NJ
Posts: 6,886
The sensors are the same. The plugs are just keyed different.
__________________
2003 TJ, 33" BFG AT, 2" BL, 2" BDS spring lift, Truck Lite headlights, Homemade sunrider top.
Neil F. is offline   Quote
Old 08-15-2014, 02:39 PM   #16
Newb
 
Join Date: Jun 2013
Posts: 13
on an 05 tj it is a 7/8 box wrench. hit with PB Blaster and let it sit for an hour...loosen nut, remove sensor, unplug from harness, and repeat in reverse order with new sensor. Do not get Bosch....they often come right back up and foul the system, giving you error codes again and check engine light. each sensor if OEM is 45$-65$ each. on an 05 wrangler rubicon there are four. two before the minicats, up close to the engine manifold and two after the mini cats.

marylandrubi is offline   Quote
Reply

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 11:42 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, Gladiator, Mopar and Grand Cherokee are copyrighted and trademarked to FCA US LLC.
Wranglerforum.com is not in any way associated with FCA US LLC.