Diagnosing Codes - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ General Discussion Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 04-10-2009, 05:27 PM   #1
Newb
 
Join Date: Apr 2009
Location: Flint, MI
Posts: 6
Diagnosing Codes

Hi guys! Just got my first Jeep earlier this week. First day off the lot the check engine light came on. Of course, it's an as-is deal so I can't take it back in and have them fix it. So, I was wondering if anyone here could give me some insite.

We looked up the codes the computer gave us and found that they were for misfires and the oxygen sensor.

Our first theory was that the spark plugs/wires were bad, but it seemed a bit weird that 4 of 6 would have went bad at once, but the dealer might have hid that, too. Before I spent the money to change them all I wanted to see if there may be something underlying one of you might have run into before.

It's a '97 Wrangler Sport, btw.

Codes: P0300, P0301, P0302, P0303, P0306, P0138

Babs is offline   Quote Quick Reply
Old 04-10-2009, 05:33 PM   #2
Jeeper
 
TerryFaust's Avatar
 
Join Date: Oct 2008
Posts: 137
change your o2 sensors, about 75 bucks each

__________________
2000 Jeep Wrangler Sahara TJ
S&B Cold Air Intake
31'' BFG A/T
4.0L I-6 5SPD Man
"going topless"
Roads? Where were going we dont need roads.
TerryFaust is offline   Quote Quick Reply
Old 04-10-2009, 05:52 PM   #3
Newb
 
Join Date: Apr 2009
Location: Flint, MI
Posts: 6
I was planning on that. Will that fix the misfiring messages, also? Or will I just have to change it and find out?
Babs is offline   Quote Quick Reply
Old 04-10-2009, 05:58 PM   #4
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 31,527
Images: 2
Here's how to display your engine's diagnostic codes, this method works for most model year TJs with the exception of late-model 98 to early 2000 or 2001 or so: Turn your ignition key on-off-on three times within five seconds and then leave it in the On position. Wait, and eventually any stored codes will display in your odometer as well as causing the Check Engine light to flash the codes... as in five flashes, pause, five flashes would equal a '55' code. If you did the procedure correctly, you will at least get the 55 code which indicates the cycle worked properly and that no more codes follow. The 55 code will always follow any other codes present.

Post the codes up here and we'll be able to decipher them for you. I'd post up the list of codes for you so you don't have to wait but I'm at work and don't have the list bookmarked. Maybe someone else can post up the link the the older two-digit DTC codes like will come up on his '97 TJ.
__________________
Remember that having a different opinion doesn't also require one to be a jerk when expressing it.

When you have a choice, buy American.

Jerry Bransford is online now   Quote Quick Reply
Old 04-10-2009, 06:37 PM   #5
Newb
 
Join Date: Apr 2009
Location: Flint, MI
Posts: 6
Did what you said. These codes came up:

12, 21, 43

After 43 came up, it continued to show up. No other codes came up.
The check engine light was flashing for all the codes.
Babs is offline   Quote Quick Reply
Old 04-10-2009, 07:28 PM   #6
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 31,527
Images: 2
Ok I don't need the list of codes to decode those, I'm very familiar with that particular set of codes.

The 12 is pretty much normal, it just means the battery has been disconnected in recent history. The 21 code indicates a bad 02 sensor, likely the one nearest to the engine, and the 43 codes that continued to show up? That just means there are multiple 43 codes... you didn't wait long enough for them to finish and the 55 code to show up.

The multiple 43 codes indicate multiple cylinder misfires. I have had as many of three of them on my '97 TJ... like 12 43 43 43 55. There is a TSB (technical service bulletin) for multiple 43 codes. There was a bad batch of weak valve springs installed into '97 and early '98 4.0L engines. The are a common cause of these misfires and the TSB consists of replacing the springs and cleaning up the combustion chambers because the bad springs can cause the combustion chambers to become loaded with carbon.

Unfortunately if the valve springs aren't replaced soon after the misfires start happening, the valves or valve seats can burn which then requires a valve job. It often takes a valve job and new springs to get rid of the 43 codes that will come back off and on if you don't do anything about them.

Or you can often find new ready-to-install 4.0L heads for $500 or so which would mean you can avoid a valve job which can easily exceed that $500 by the time the machine shop starts telling you all the new parts they need to "really do the job right" as mine did.

And no, replacing the plugs, distributor cap, rotor, ignition wiring, fuel injectors, cleaning the fuel injectors, fuel injector wiring harness, ignition coil, etc. will not likely cure the 43 codes. Doing so certainly doesn't cure it for most '97/98 TJ 4.0L engine owners.
__________________
Remember that having a different opinion doesn't also require one to be a jerk when expressing it.

When you have a choice, buy American.

Jerry Bransford is online now   Quote Quick Reply
Old 04-11-2009, 12:51 PM   #7
Newb
 
Join Date: Apr 2009
Location: Flint, MI
Posts: 6
Thank you so much! I'm sure that information will be very helpful for my mechanic buddies to fix what I can't do myself.
Babs is offline   Quote Quick Reply
Old 04-12-2009, 03:27 AM   #8
Jeeper
 
dwdrums801's Avatar
 
Join Date: Aug 2006
Location: Long Island, NY
Posts: 1,298
Quote:
Originally Posted by Jerry Bransford View Post

The multiple 43 codes indicate multiple cylinder misfires. I have had as many of three of them on my '97 TJ... like 12 43 43 43 55. There is a TSB (technical service bulletin) for multiple 43 codes. There was a bad batch of weak valve springs installed into '97 and early '98 4.0L engines. The are a common cause of these misfires and the TSB consists of replacing the springs and cleaning up the combustion chambers because the bad springs can cause the combustion chambers to become loaded with carbon.

Unfortunately if the valve springs aren't replaced soon after the misfires start happening, the valves or valve seats can burn which then requires a valve job. It often takes a valve job and new springs to get rid of the 43 codes that will come back off and on if you don't do anything about them.

Or you can often find new ready-to-install 4.0L heads for $500 or so which would mean you can avoid a valve job which can easily exceed that $500 by the time the machine shop starts telling you all the new parts they need to "really do the job right" as mine did.

And no, replacing the plugs, distributor cap, rotor, ignition wiring, fuel injectors, cleaning the fuel injectors, fuel injector wiring harness, ignition coil, etc. will not likely cure the 43 codes. Doing so certainly doesn't cure it for most '97/98 TJ 4.0L engine owners.

Can this be the problem in a 99? I have bad mis fires and cant figure out why, I have changed plugs, distributor and cap, rotor, ignition wiring and fuel injectors and the wiring harness but still get the random miss fires...
__________________
06 Rubi Unlimited, 3.5" Rubicon Express LA, OME Shocks, Metal Cloak Aluminum Bumper, Warn Winch, Power locks/remote start.
dwdrums801 is offline   Quote Quick Reply
Old 04-12-2009, 09:53 AM   #9
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 31,527
Images: 2
Quote:
Originally Posted by dwdrums801 View Post
Can this be the problem in a 99? I have bad mis fires and cant figure out why, I have changed plugs, distributor and cap, rotor, ignition wiring and fuel injectors and the wiring harness but still get the random miss fires...
I dunno, I thought the valve spring problem was taken care of by '99. A compression check might help, it might pinpoint a cylinder leaking from valves that aren't sealing well.
__________________
Remember that having a different opinion doesn't also require one to be a jerk when expressing it.

When you have a choice, buy American.

Jerry Bransford is online now   Quote Quick Reply
Old 04-22-2009, 10:21 PM   #10
Newb
 
Join Date: Apr 2009
Posts: 1
Hey, I just got this problem (P0300) resolved. I got a 05 wrangler w/2.4L, It turns out that the double platnum plugs I put in dont work with 99 and up Jeeps. The dealer told me to put in a set of regular plugs ( copper) and most likely that would resolve my issue. I thought they were full of it but, I went ahead and swapped them. " Problem Gone!" Sounds crazy but it took care of the problem. Quick cheap way to trouble shoot. I spent $9.00 not bad for a problem that was driving me nuts! Good Luck!
jerjeep is offline   Quote Quick Reply
Old 04-23-2009, 12:35 AM   #11
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 31,527
Images: 2
Quote:
Originally Posted by jerjeep View Post
Hey, I just got this problem (P0300) resolved. I got a 05 wrangler w/2.4L, It turns out that the double platnum plugs I put in dont work with 99 and up Jeeps.
No, the issue is with single-tipped platinum plugs and not with double-tipped. The dealer rep you spoke to doesn't understand the issue. Double-tipped platinum plugs like the Champion 7034 and Autolite APP985 plugs are well known to work in the newer engines. The newer engines run fine on either conventional plugs or double-platinum plugs, just not single-platinums. The dealer's TSB (technical service bulletin) doesn't explain that double-tipped platinums work fine, but it's too hard for them to know what kind of platinum plug they're looking at so they just replace any platinum with a conventional plug. Simpler for them, but the limited information the dealer service writers get from the TSB can be misleading to them.
__________________
Remember that having a different opinion doesn't also require one to be a jerk when expressing it.

When you have a choice, buy American.

Jerry Bransford is online now   Quote Quick Reply
Old 04-24-2009, 02:55 PM   #12
Jeeper
 
Join Date: Apr 2009
Location: UAE
Posts: 20
Quote:
Originally Posted by Jerry Bransford View Post
Here's how to display your engine's diagnostic codes, this method works for most model year TJs with the exception of late-model 98 to early 2000 or 2001 or so: Turn your ignition key on-off-on three times within five seconds and then leave it in the On position.
Dear All,
I am a new user and this is my first Post.

I have a TJ 98 has a 280,000 KM on it.
I am having a problem with Oil Pressure Gauge, where the gauge indicates low pressure, and therefore check engine lights is on.

When I try to get the codes by turning the key ignition key on-off on off (five times) while pressing the odometer, all I get is that the odometer showing:
1111111
2222222
3333333
4444444
and so on,

All the Gauges will move half way and pause, then all the way to max and pause; and then back to original place of the Zeros.

I do not see any codes through flashing Check engine.

(Anyhow I sorted out the Oil Pressure thing, but forcuriosity I am trying the code thing)

regards,,,
AlBahhar is offline   Quote Quick Reply
Old 05-02-2009, 09:40 PM   #13
Newb
 
Join Date: May 2009
Posts: 1
Dear All,
I am a new user and this is my first Post.

I have a TJ 98 has a 280,000 KM on it.
I am having a problem with Oil Pressure Gauge, where the gauge indicates low pressure, and therefore check engine lights is on.

When I try to get the codes by turning the key ignition key on-off on off (five times) while pressing the odometer, all I get is that the odometer showing:
1111111
2222222
3333333
4444444
and so on,

All the Gauges will move half way and pause, then all the way to max and pause; and then back to original place of the Zeros.

I do not see any codes through flashing Check engine.

(Anyhow I sorted out the Oil Pressure thing, but forcuriosity I am trying the code thing)

regards,,,








So is this just a test f the dashboard funcion? I did not see a code either
christianvfrench is offline   Quote Quick Reply
Old 01-19-2011, 05:16 PM   #14
Newb
 
Join Date: Jan 2011
Posts: 1
Malfunction indicator light (MIL)

Hey ya'll! I'm taking care of my husband's 2009 Jeep 4x4 while he's deployed and the MIL came on. I checked the gas cap to make sure it was tight and it seems to be fine. I did the back and forth on/off thing to show the display codes and it flatlines _ _ _ _ _ _ then displays D0ne. But it's not showing any codes or flashing. And the malfunction indicator lamp is still on. btw can you please email me at moussiemoose@yahoo.com if you reply. not sure if this forum automatically lets you know you have a response.
Miss_Moose is offline   Quote Quick Reply
Old 01-22-2011, 08:43 AM   #15
Jeeper
 
Drifty's Avatar
 
Join Date: Sep 2010
Location: Portland, ME
Posts: 29
I have a 2006 Wrangler X that is new to me. I just had it serviced at the 60k B maintenance recommendation although it is really at 66k...since I don't know the vehicle maintenance history I wanted to have a good starting point. On the third trip since servicing the MIL came on. I used Jerry Bransford's display code trick and P 0153 came up then done. I'm going to bring it back to the place I got it service on monday, but any help on understanding the problem would be a lot of help.
Drifty is offline   Quote Quick Reply
Old 01-22-2011, 09:07 AM   #16
Jeeper
 
Join Date: Mar 2010
Posts: 23
I believe that is an O2 sensor warning. My 06X pushes it intermittently. Usually gumout or seafoam will do the trick to reset it. It take about 2 fillups to reset for me though.
Tigerfan is offline   Quote Quick Reply
Old 01-22-2011, 09:17 AM   #17
I am JD & It's my Dream

WF Supporting Member
::WF Administrator::
 
JDsDream's Avatar
 
Join Date: Jan 2009
Location: The Peach State
Posts: 26,949
Images: 4
P0153 Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 1)

My 06 shows this code off and on all winter and has been doing it for 3 years now. Usually after or during a rain storm. The CEL comes on and will show for several starts and then go back off by itself. It has never effected the performance nor does the computer store the code. I've asked for advice on this several times here on the forum and never gotten a response to it. I believe that it has more to do with weather conditions than a mechanical issue.
__________________
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 online now   Quote Quick Reply
Old 01-22-2011, 09:21 AM   #18
I am JD & It's my Dream

WF Supporting Member
::WF Administrator::
 
JDsDream's Avatar
 
Join Date: Jan 2009
Location: The Peach State
Posts: 26,949
Images: 4
Oh and for future reference

Generic Check Engine Light Codes - Complete Automotive Code Diagnosis Help

This link will tell you what the code means or you can go to Google.com and type in the code and you will find tons of info on what it means and what has been done to resolve 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 online now   Quote Quick Reply
Old 07-08-2011, 06:40 PM   #19
Jeeper
 
nomad-sal's Avatar
 
Join Date: Mar 2009
Location: San Francisco,CA
Posts: 21
my 2001 TJ has the check engine light ON. I followed the procedure to see codes as below
1) Press and hold the odometer reset button
2) Turn the ignition key to the RUN position
3) Let go of the odometer reset button

The odometer display showed a series of 8's dancing, then is showed 'SoF 2.1' this is the software version, then it showed '00000000' followed by 'NoFaults'. After this the instrument panel check began,where all of he lights came ON and off and the needles moved.

So what does this mean ? I have no faults, but then why is the 'check engine' light ON constantly for 1 week. I have opened and closed the fuel tank cap. I am due for a service, and engine oil is slightly below the desired level. Please advise.
__________________
2001 Jeep Wrangler Sport 4WD, stick shift, 4.0L, solar yellow, dual top, 68K miles
nomad-sal is offline   Quote Quick Reply
Old 07-08-2011, 06:58 PM   #20
▄▌ee▐▀

WF Supporting Member
 
Hardermods's Avatar
 
Join Date: Jul 2009
Location: Kansas
Posts: 1,298
Doing the test where you hold the odmeter button is just a self diag for the cluster.

To check codes you don't hold any buttons, turn the key on-off 3 times ending with it in the on postion.

It will then display any codes like with a P0000, 0000 being the codes you have followed with a "done" to show no more codes. Then search here or post what codes you come up with
Hardermods is online now   Quote Quick Reply
Old 07-08-2011, 08:01 PM   #21
Jeeper
 
nomad-sal's Avatar
 
Join Date: Mar 2009
Location: San Francisco,CA
Posts: 21
I tried that (on-off 3 times). Nothing happened. Did not show any codes, niether did the check engine light flash. I read another post that for 2001 TJ model the on-off 3 times within 5 seconds does not result in codes being displayed
__________________
2001 Jeep Wrangler Sport 4WD, stick shift, 4.0L, solar yellow, dual top, 68K miles
nomad-sal is offline   Quote Quick Reply
Old 07-08-2011, 08:10 PM   #22
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 31,527
Images: 2
How long did you wait after the last turn to the 'On' position? The codes don't come up immediately, give it at least several seconds. I'm pretty sure that ability returned in time for the 2001 model.
__________________
Remember that having a different opinion doesn't also require one to be a jerk when expressing it.

When you have a choice, buy American.

Jerry Bransford is online now   Quote Quick Reply
Old 07-08-2011, 09:05 PM   #23
▄▌ee▐▀

WF Supporting Member
 
Hardermods's Avatar
 
Join Date: Jul 2009
Location: Kansas
Posts: 1,298
Yeah it should work. I've got an 01 and I pull them like that when I'm on the road
Hardermods is online now   Quote Quick Reply
Old 07-08-2011, 09:11 PM   #24
Jeeper
 
nomad-sal's Avatar
 
Join Date: Mar 2009
Location: San Francisco,CA
Posts: 21
I waited for over 2 minutes and no codes. Wonder what I am doing wrong. The codes show up on the LCD panel in place of the odometer reading right ?
__________________
2001 Jeep Wrangler Sport 4WD, stick shift, 4.0L, solar yellow, dual top, 68K miles
nomad-sal is offline   Quote Quick Reply
Old 07-08-2011, 09:12 PM   #25
Jeeper
 
nomad-sal's Avatar
 
Join Date: Mar 2009
Location: San Francisco,CA
Posts: 21
Here is the post that says for 1998-present TJ the 3 times on-off does not work. http://www.wranglerforum.com/f5/tj-error-codes-358.html
__________________
2001 Jeep Wrangler Sport 4WD, stick shift, 4.0L, solar yellow, dual top, 68K miles
nomad-sal is offline   Quote Quick Reply
Old 07-08-2011, 09:56 PM   #26
Jeeper
 
Join Date: Jun 2011
Location: Kentucky
Posts: 274
I thought u had to do the key thing like 5 times and then a code will pop up. I did it on my 03 tj awhile back when my check engine light came on and got the code and Googled it and got what the code was.
kodiakjoe1978 is offline   Quote Quick Reply
Old 07-09-2011, 12:22 AM   #27
Jeeper
 
JYJeep's Avatar
 
Join Date: May 2010
Location: Washington DC
Posts: 286
Images: 2
'05 LJ. three time Key sequence described above delivers the codes. For me usually a O2 sensor downstream that periodically surfaces. Hold the odometer trick gets a real fancy flashing cluster as it runs it's own diagnostic.
JYJeep is offline   Quote Quick Reply
Old 07-09-2011, 01:16 AM   #28
Jeeper
 
nomad-sal's Avatar
 
Join Date: Mar 2009
Location: San Francisco,CA
Posts: 21
Thanks everybody, I finally got the codes from my 01 TJ. I think previously I was doing the on-off one extra time, that was my mistake. Now the code it shows is P0442. So this is the leak in EVAP thingy. Google search showed me recommendations. I am taking it to the dealer for service tomorrow, I will have them find out where the leak is. I have tightened the gas cap.
__________________
2001 Jeep Wrangler Sport 4WD, stick shift, 4.0L, solar yellow, dual top, 68K miles
nomad-sal is offline   Quote Quick Reply
Old 07-09-2011, 10:20 AM   #29
▄▌ee▐▀

WF Supporting Member
 
Hardermods's Avatar
 
Join Date: Jul 2009
Location: Kansas
Posts: 1,298
If you want to look into it before going to the dealer, Id rec. checking the lines along your evap canister on the drivers inner fender, the hoses there are prone to cracking and causing that code.

Hardermods is online now   Quote Quick Reply
Old 07-11-2011, 11:28 AM   #30
Jeeper
 
nomad-sal's Avatar
 
Join Date: Mar 2009
Location: San Francisco,CA
Posts: 21
Thanks Hardermods. The dealer was asking $75, just to run diagnostics. I told him I already have the code it is P0442 and it indicated EVAP system. Looked like he wanted to make some money off of me. I did not get the work done at that dealership. I will check the lines as advised by you here after I get off from work today. Thanks again.

__________________
2001 Jeep Wrangler Sport 4WD, stick shift, 4.0L, solar yellow, dual top, 68K miles
nomad-sal 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
Error Codes amara8 YJ Tech Forum 13 10-11-2009 06:43 PM
Reset codes xethos YJ Tech Forum 2 02-14-2009 08:13 AM
PCM issue? Details and codes inside Cole TJ Tech Forum 1 10-27-2006 05:47 AM
2002 4.0L Wranger X giving OBD Codes again AggieChris TJ Tech Forum 2 07-25-2006 11:19 AM
TJ Error codes khenderson TJ Tech Forum 3 08-19-2005 12:36 AM



» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 01:57 PM.



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