went off road for the first time on Thursday 2/23, no big trails just some up hills to test out the 4wd, which worked great. on my way back to the highway went through some deep mud. made it through okay, but when i came out my xj stalled and shut off. 5 min later started right back up but the CEL is on. checked for codes and got a code 41, Alternator field control circuit open or shorted. drove to work today 2/24 but battery gauge showed only 9-11 volts, usually runs 14-18. on the drive home gauge was showing 9v and dropping fast until it finally died on me. put in a fresh battery and started right up, but still showing 9-10v. is this a battery problem? Alternator? PCM issue? im fairly new and have little mechanical exp, so really any info helps. thanks to you all.

 

You need an alternator. The brushes are worn out and not making contact on the slip rings.

 

I agree with Bustedback.

A code 41 is almost always a failing alternator.

Replace it. Go NEW, not rebuilt/reman.

 

to tj wlaker and bustedback thanks for the help i thought thats what it might be just wanted to be sure, will look into it this week when i have time off.

 

Of course you will see if any wires are off or busted, or if your belt is messed up following the fine advise above.

Just "in the name or science", you could try blasting it good at the car wash if you have time. There are vents for things including the rectifier. Shorted with mud/debree, that might not work right. You're not going to hurt it!