Starting Issue/Headlights on/Transmission Alert on Screen

[Nice_Rumble]

My wife has been having a problem with her car not starting. She presses the start button and gets a large exclamation symbol and something about the transmission not being in park (I think) on the menu screen. Headlights are on and she sometimes runs the battery dead before I can resolve it for her. I tell her to turn off the headlights manually so as not to kill the battery. I have been able to get it back to normal by playing with the park button, starter on/off button and keeping my foot on the brake. But it takes awhile as I'm not sure what sequence is actually effective. My seat of the pants diagnosis of the why this is happening is pilot error. I think she is forgetting to put the transmission into park before tuning the car off. Given that this car does not have a traditional gear selector it's not intuitive when placing the car into park. If it's dark or your in a rush I can see how one might skip pushing the park button and go directly to pushing the start/stop button and think all is good when it's not. Anyone else experience this?

[qbee42]

First, kindly update your profile so we have some idea which Prius she drives.

The Prius has no shiftable transmission. Powering down the car in D does exactly the same thing as pressing Park and then powering down.

With the Gen II Prius, you can get some funny error messages if you leave the door open or have a loose gas cap. Likewise a bad 12V battery can cause all sorts of mysteries. I suspect the 12V battery given your description. It might be time for a replacement.

Tom