Ok this morning I had to jump start my XJ. Now the check engine light is on. Will that eventually go off or do I need to have the code reset?

Thanks

The codes don't reset themselves, no. The light might even go off, but the code will still be stored. Autozone Oreilley etc. will read the code for you and reset it.
If your battery was dead you need to get it charged. Your alternator won't charge it properly and a battery that isn't fully charged can kill the alternator.

Strategy for a check engine light is always the same. Read the code.

As kjc mentioned, some parts stores will do this for you for free if you don't have access to a code reader or a scan tool.

Post the code here for comment.

And yes, figure out why you needed a jump. Connections, battery problem or charging system problem are likely suspects. Another thing you can do at the parts store if you go there to get the code read is to have your battery "load tested". Another free service that parts stores offer.

What year is your XJ. I have an 97 and is has a self diagnostic feature. Turn the key on, off, on, off, on. Then the code # will appear in the odometer and the check engine light will flash the code also. took me several tries to get it to work. you need to do it pretty quickly.
A haynes book will decifer the code but if you don't want to spend the $20 for the book just post it here and me or someone will try to tell you what it means.
My tps quit the other day and gave me a code. One of the codes I received was a 12(i think) which said the battery was disconnected. Didn't make sense to me but maybe thats your only issue.

Retrieving OBD codes on the Jeep Cherokee (XJ)

OBDI models (1991-1995) - Start with the ignition off. Within five seconds, switch the key on, off, on, off, on. ("On" is NOT "Start" and "Off" is NOT "Lock"). The "check engine" light will flash. Count the flashes. Each code is a two digit code, so a (for example) 23 would be FLASH FLASH (pause) FLASH FLASH FLASH (long pause). It will never flash more than 9 times, so watch for those pauses!

OBDII models (1996 and “SOME” 1997 models) Put the key into the ignition, push down the odometer reset button, then turn the key to RUN with your finger on the button - and then release the button. The odometer will go through 1111111 through 999999, then display the car's serial number. It will then show the 2 digit error codes. The2 digit code is helpful, but it is not as specific as the full PXXXX code, which is only available using a code reader or scan tool, so generally I recommend using the code reader or scan tool. But if you have a CEL and don’t have access to a code reader or a scan tool, try the odometer technique to point you in the right direction until you can gain access to a code reader.

Note: The above OBDII odometer technique works only for 1996 and early 1997 model XJs, so while it might work on one 1997 XJ, it might NOT work on another! Once Chrysler made the change during the 1997 build year, for anything built after that date through 2001 you will need either a code reader or a scan tool to retrieve the codes.

Ok tried the on, off, on, off, on sequence and the check engine light was steady. Off to have it read. Thanks for the tips gentlemen!

Ok folks. Had the computer read. It was only a "low voltage" code....i believe he said a "53"??? Mechanic reset for me and seems all is good, no codes after resetting and driving about 50 miles. Off to buy a battery.

Thanks for all yalls advice!

My 1996 Cherokee had the check engine light come on and started running rough when idling. I turned the key on/off three times and counted the flashes and the lights flashed"34". I did some research and I don't see an error code "34". Any suggestions or different methods od determining the check engine code? thanks

check one of these lists... could help you out..... let us know....

1 https://www.cherokeeforum.com/f2/jee...di-obdii-3341/

2 http://www.fixjeeps.com/jeep-check-engine-codes.html