Kia Picanto problem

I have a problem with the electric power steering on my Kia Picanto. The steering works very well,
but at certain times the ESP warning light comes on and the steering immediately becomes
stiff. After that, the engine shuts off and restarts, and the steering works
fine again. After a while, the same thing happens again. I would appreciate any help you can offer.

The problem is most likely with the electric power steering. As for it stalling, I imagine that's a safety measure in case of steering failure. Have it checked by an electrician. If that's too expensive, remove the torque converter and go with mechanical steering; it's lighter and cheaper than leaving it installed. If you have the means, you can repair it.