Prius 2007 switches to neutral or park while in motion

My Prius 2007 switches to neutral or park while in motion. I have a couple of codes C1241. Sometimes the screen displace 12v battery and check hybrid when it happens. But immediately I turn the car off and back on the screen returns to normal and it drives. Again, I noticed my 12v battery drains doesn't charge when I did the self diagnosis on the monitor. I bought another new battery it's the same issue. What could be the problem. I've also changed the gear sensor.