2013 MKX shuts down

I have a 2013 MKX with approx 76000 miles. Well maintained. Twice while driving, the car shuts down, and I can only drive 2 mph, after I pull over to turn car off, then restart - it drives fine. There is a "wrench" indicator on dash that pops up. The first time, I had been driving for quite a while going 50-55 mph. This morning, I drove less than a mile, went in store, came out, started car and was pulling out onto the road. I pulled off the road, turned car off and restarted and it drove fine back home.\

The owner's manual says to take to dealer... Any thoughts as to what I'm looking at?

thank you.