One problem related to anti-theft controller has been reported for the 1999 Jeep Grand Cherokee. The most recently reported issues are listed below.
I would have put igniotion/key as the affected parts, but that's not an option. So I'm driving down the road, and all of sudden it just stops running. Literally on southfield road. Think it was just a fluke I continued to try and drive it. Because the first time it started right back up. But now, it turns off at a light, during a turn, going 25mph, 45mph. . . Basically whenever it feels like. I have a son that is a permit only driver, and can't allow him for safety reasons to be driving this vehicle. I went to the mechanic and this is what I was told, there is a part in the ignition system that sends a signal to the chip in the key. When that stops sending the signal the vehicle turns off. Great anti-theft idea! it's so dangerous. Mechanic says the part is $100+ and then the original keys 'may not' reprogram, which means an extra $60 per key, plus programming. There is a reason the dealer keeps it in stock, gotta know it fails. This part should be recalled before someone gets hurt because the vehicle decided to stop running on the expressway.