I have a 96 xj and the check engine light came on. My neighbor has a scan tool that I borrowed to run the codes but it just sits and sits and then tells me the Jeep is not responding. So making sure it wasnt the scanner I plugged it into my wifes car and it came right up. Plugged it back into the jeep nothing again. Jeep not responding. Help!! 96's are OBD2 correct? Anyone have any ideas?

 

It sounds like you may have a problem with your connector on the jeep. I think you can flash the codes on these jeeps like the older jeeps using the key trick.

Turn the iginition key on and off three times then leave the key one. The check engine light should flash codes at you. It works on my 95 anyway!

Thx-Ace

 

96 is an OBDII.
key trick will work.

You might have a bad wire(s) for the OBDII connector.

 

Yes the key trick works but I dont know what O2 sensor to replace and I seem to have problems counting the flashes. I dont usually get them right and write down the wrong code!! But yeah the scanner works on other cars I have just wont work on the XJ! If I were to get an OBD2 off a junkyard Jeep would I be able to splice it in, in place of mine now or is there a way to test my wires to see if one is bad or not? Thanks

 

How does the key trick work on OBD-II?

 

http://www.go.jeep-xj.info/HowtoECUcodes.htm
This is a link to what it is and how to do it

 

I thought OBD-II codes were 5 digit......1 alpha and 4 numeric, ie., P1281, no?

 

Or maybe the CEL is on b/c there is a communication problem between modules. The Jeep maybe really not responding. Just a thought!

 

OBD codes are 5 digits but when you do the key trick the cel flashes sequences of 2 digit numbers since there is no obvious lcd screen for a readout. So how do I figure out if it is really not responding or communicating and how the hell do I fix that issue? Im mechanically inclined but there are just some things that I have never had to deal with so have never had to learn!!

 

Anyone?

 

check to make sure you are getting power to the DLC at pin 16. with the key in the on position you should get 12v between pin 16(+) and pin 4 or 5(-). i think 5 is a chassis ground and 4 grounds though the PCM. if you have a breakout board you should see the LED's flashing to let you know there is communication to the DLC.

 

Does it still run?
I had a CPS short out (so it didn't run), the CPS shorted out the 5V power supply from ECU, so we couldn't read codes. Any of the sensors could theoretically do this (Crank position sensor, camshaft position sensor, throttle position sensor). Of course, if it still runs, this is not your problem.

 

Yes it still runs.