As someone else alludes, this should not happen. I hope what you mean is that the steering wheel lost power, which is normal when the engine dies. It will be difficult to turn, but it will do so with some force. If it really locked up, get it to the dealer and have them find out why ASAP. Could be very dangerous.

Also, a couple weeks ago my Jeep died. The horn honked, the wipers (front and soccer mom rear) ran, and the soccer mom sprayer hosed down the rear window. All of this with all of the appropriate switches untouched. Then the engine died. Immediately started up. Did it a second time two days later. I did some research and this is a sign that the TIPM is bad. Except in the cases I found, they were not able to start their vehicles again until the TIPM was replaced. Anyway, at 126K miles I don't have any warranty options. I pulled out the TIPM and cleaned out the relatively clean connectors, pushed all of the fuses down, and said a little prayer. Going on a week now without a recurrence. If it happens again, I plan to replace the TIPM.

 

This happened to quite a few people back in 07 when the new models came out. It happened to the wifes 07 JKU a few times. Had it in for checkes at least 4 times back in 07. The dealership checked it, flashed it, and replaced the PCM, it seemed OK for about 2months then it happened again. They ended up finding corrosion on the terminals of the TIPM, so they replaced it along with the wiring harness. Hasn't happened since.