Possible access to OBD-II codes for 97+ XJs?

[Rob Mayercik]

Buddy of mine with an '04 Liberty sent me this link recently:

http://www.allpar.com/fix/computer-codes.html (http://www.allpar.com/fix/computer-codes.html)

We tried it on his truck, and it seemed to work. If the 97+ XJs use the same interface, perhaps this may finally be the way to duplicate the OBD-I CEL blinker system?

Any 97+ owner care to try it out and report?

Rob

[prb24]

Thanks for the info...I'll try it when I get home, although I don't believe I have any codes to see.

[BCParker]

My '97 doesn't use that on-off-on-off-on BS- Just hold down the trip reset button and turn to ON- mine flashes 111111,222222,333333,444444,etc, no codes there.

[thewrath]

just tried the on-off-on-off method with no luck on my 2000 XJ, also tried holding the odometer button down which started the self test but still didnt show codes. and to add to it, i definatly have a code because my check engine light is on

[BCParker]

I don't know what to tell ya.. I always thought it would show any codes after it finished testing the guages, but I've never had a check engine light on so I just assumed no codes would show. maybe I'll unplug a sensor and see what shows up.

[Gridikal]

I don't know what to tell ya.. I always thought it would show any codes after it finished testing the guages, .

It does. I've used it several times.

[BCParker]

so, just to be clear, if after showing 999999 it just displays the current odometer number there are no codes?

[Gridikal]

so, just to be clear, if after showing 999999 it just displays the current odometer number there are no codes?


Righto

-easiest way to check is to unplug the battery and let the computer reset- it will throw one.

[jeepurnaz]

the dash button only checks the dash, it will not show check engine codes.

[JEEPZZ]

The key on-off thingy only works on the 97 XJ. For 98 and newer you'll need a scanner.
You need to release the trip button after the last key cycle to get the codes otherwise you'll just get the instrument panel check (cycling of the gauges, lights & count up of the odometer LEDs)

[Gridikal]

Glad I got a '97 then :D

[BCParker]

just checked my 97, just pressing the trip reset and turning on starts gauges going, but no codes given. going on-off-on-off-holdbutton-on does self test then shows 55_____- on the odometer, and blinks 5, 5 on the check engine light. 55 means end of codes/all clear right?

orig posted by me- "my '97 doesn't use that on/off/on/off BS" - I stand corrected. thanks all

[Bounty Hunter]

We could do a self-diagnostic on our old '98 Classic:
Ignition off, push and hold trip reset button.
Turn ignition to run (not start).
Turn ignition back to off, then release trip reset button.

OBDII codes will then be displayed in the odometer window. A cycling of 999999, 888888 etc. and the guages cycling means you released the trip reset button too soon.

[60thAnivrsryXJ]

As far as I know there is no way in any OBD-II vehicle to flash the diagnostic trouble codes. The government mandates what features OBD-II systems have to have. One of them is that it can't flash the codes. So basically it is against the law for a vehicle manufacterer to allow that. I could be missing some exception somewhere but that is what I was taught in computer diagnostics class in automotive school.

[Hayden]

We could do a self-diagnostic on our old '98 Classic:
Ignition off, push and hold trip reset button.
Turn ignition to run (not start).
Turn ignition back to off, then release trip reset button.

OBDII codes will then be displayed in the odometer window. A cycling of 999999, 888888 etc. and the guages cycling means you released the trip reset button too soon.


I just did that on my 98 classic......It showed 2.3 any idea what that means? My check engine light is not on so i dont think its a code.



Hayden

[Rob Mayercik]

As far as I know there is no way in any OBD-II vehicle to flash the diagnostic trouble codes. The government mandates what features OBD-II systems have to have. One of them is that it can't flash the codes. So basically it is against the law for a vehicle manufacterer to allow that. I could be missing some exception somewhere but that is what I was taught in computer diagnostics class in automotive school.

Well, all I can tell you is that it worked on my buddy's liberty (all he got was "done").

Perhaps it's only good for '04s, but did anyone actually try ON-ACC-ON-ACC-ON? that's what the link I posted (at least, the first page that loads) says to do.

Maybe it won't work, and maybe it will. My XJ's a '92, so I can't try it myself.

Rob

[BCParker]

As far as I know there is no way in any OBD-II vehicle to flash the diagnostic trouble codes. The government mandates what features OBD-II systems have to have. One of them is that it can't flash the codes. So basically it is against the law for a vehicle manufacterer to allow that. I could be missing some exception somewhere but that is what I was taught in computer diagnostics class in automotive school.

my 1997 OBD II shows the code on the odometer AND flashes the check engine light.

[Hayden]

I just did that on my 98 classic......It showed 2.3 any idea what that means? My check engine light is not on so i dont think its a code.



Hayden


Anybody? any ideas what the "2.3" means?


Hayden

[Bounty Hunter]

23** Intake manifold air temperature sensor input above maximum acceptable voltage.
or
Intake manifold air temperature sensor input below minimum acceptable voltage.

We had this code a few times on our '98 XJ.

[Hayden]

Shouldnt the code come out as a four digit number? I just got a 2.3


Hayden

[thewrath]

any chance that was the trip odometer reading? hate to point out the obvious, but ya never know.

[BCParker]

Shouldnt the code come out as a four digit number? I just got a 2.3


Hayden

I've never had a code other than 55, so I don't know, but for two digit codes try this chart

http://www.hesco.us/obd.html

it confirms 23 is intake air temp voltage

-B

[bjoehandley]

I'll have to try that on my '98, I knew that worked on my K-Cars, but thought I couldn't do that on the Jeep.

[PDeeXJ]

I just get the 2.3 reading on my 98, but the check engine light wasn't on beforehand. And no that's not from my trip reading.

[Hayden]

Hmmm, thats interesting. There has to be something to that.

Hayden

[Bounty Hunter]

The self-diagnostics give a 2-digit code. OBDII scanners generally give a 4-digit.

[Li0nHart]

Anybody? any ideas what the "2.3" means?


Hayden

Firmware version of your PCM....I asked a similar question at jeepforum.com...

http://www.jeepforum.com/forum/showthread.php?t=199268