I have a 99 Jeep Cherokee XJ Sport and have been having some problems and am getting check engine lights that come on for a few seconds while I am experiencing problems, then go off again.

Was wondering if anyone knew how to do the self diagnostic "key trick." I mean I have tried all ways. I tried the gauge test. The gauges work, but no codes show, not even a 55 for end of codes. I also tried the key trick by turning 3 times and even 5 times. Nothing shows on odometer and no blinking check engine light either. Shouldn't this work? Is there a special trick to it ( park break etc.)?

 

more then likely you need a scanner that will show you stored or pending codes, if your light comes on then shuts off its not staying active so you wont see it.

 

You should at least get a 55 with the key trick.
Are you the one that messaged me on Youtube?

Anyway, "On" is when the dash lights come on, but "off" is not "lock"
With the key all the way out, this position is "lock" (the steering wheel is locked)
The first position after that is "off"
Next is "on"

You need to go from "on" to "off" not lock 3 times. I usually do 5..
You should at least get a 55, my girlfriends 96 always does, and my 97 did.

 

Get a scanner... key trick is crap.
Thats what I did.

 

Scanners are $40 at walmart, they come with a book of all the codes, and what each code means. Plus you can delete codes.

 

It's my understanding the key/blinking light thing is OBD-I, '95 down. '96 up is OBD-II and requires a diagnostic scan tool, no?

 

as far as i understand the standard scan tools will not pull pending or historic codes. they only show codes that are currently displaying a light. the problem i am having is the rpm drops to zero instantly while driving 55 and it throws a light for a second. but when the vehicle regains throttle response, the light goes off instantly. motor never dies only slows to idle. also sometimes it jerks like you hi t an imaginary pothole .

not really sure why my self diagnostic isn't working...unless my ECU revision doesn't support it.

also , anyone tried the throttle cable adjustment that takes a few seconds? was wondering if it really makes a difference ?

 

Your 5 dollar scan tools will not work for stored codes like said above if you want a scanner you need to speed atleast 100 bucks for a good one, so leave your SCABMART shopping to yourself. You can always go to an auto parts store and have one of the know nothings scan your xj, or better do it yourself.

 

the know nothing already scanned it. every auto parts store tells me the same thing ..."we can't read history or pending codes...only current lights." they say a mechanic will have to do that. of course for the 100 dollar diagnostic fee .

update on symptoms of my xj . was.sitting at idle a little while ago and it just died. motor , power ,everything....

key was still in start position and absolutely no lights on dash or radio. almost like all power just stopped flowing instantly . did fire right back up though...

 

A 55 is only if there's nothing wrong though

 

no... 55 is "end of codes"

 

This one will read history - cheap and works great. If you own an XJ, you should have a code reader in your glove box.

 

91-95: Can read with an OBDI code reader or the key-on-key-off trick will work.
http://www.go.jeep-xj.info/HowtoECUcodes.htm

96-sometime in 97: The key-on-key-off trick will work BUT all you will get is a two digit code. Using a code reader or a scan tool will give you the full PXXXX code, which is much more helpful than the two digit code

Sometime in 97-01: A code reader or a scan tool is needed to retrieve codes. The key-on-key-off trick will NOT work!

 

I got a ScanGaugeII and it shows current and pending codes, and lets you reset them. As well as showing real time gauges to temperature, etc. Nice little thing.

 

did you ever figure out what your problem was?? My 96 Cherokee sport is having the same problem.. sometimes it has issues and sometimes it doesn’t.. it’s random..