Prius C No Start, No Gear Position Indicator on Dash

Hey all,

I have a 2013 Prius C Two, 129k miles, that I just wrote out a check for the final payment last week. Today I was out running errands and I stopped for lunch. I turned the car off, but left the key turned to accessory as we were eating in the car and wanted to listen to the radio. The lights were turned off, as well as the heater. We were there for no longer than 30 minutes, and when I went to start the car nothing happened. The speedo came up, but the shift indicator never lit, and the info screen in the dash got really dim. The ready light never illuminated either. Slightly panicked, I shifted the car between park and drive a few times, turned the key and got nothing. Got out, pushed to make sure it was actually in park. After about a minute of this, I turned the key and it started like normal. This has never happened to me before and I feel like this is punishment for paying the car off. It’s been 100% reliable for the last 4 years and 55k miles. From other posts I’ve read it sounds like it’s a dying 12v battery, but no one else seemed to have the exact same problem as I did. I have no clue as to the age of the battery, but I haven’t replaced it since I got the car. I should note the temperature locally hasn’t been much over freezing for the last month, and I don’t believe it’s gotten over 20°F today. Thank you for any advice!