Had to jumpstart??

Sounds like an interior light was on. Are you sure the doors were all closed tight?

If you still have the original 12v battery, it's time for a new one. It's about at its age limit.

 

To anyone needing to jumpstart Prius: Make absolutely sure that you have the battery polarity correct (pos to pos, etc.) before hooking up. Reverse polarity will cost you a lot of money. If these words don't make sense to you, don't be the one connecting clamps.

Sorry skygazer242, I add this to all the jumping threads.

 

I just replaced the 12V in my '04. Given it arrived on the boat mid Sept 2004, it was probably one of the last '04s built. If you have an early '05, yep, could be time.

I had 2 'warnings' that were not specific. The first turns out to be a 'known' indicator of a weak 12V:
You get a message: "Caution: The transmission lock mechanism is abnormal". WHY does this mean your 12V might be going south? I don't know. The message never stayed on so I ignored it. I always use the parking brake anyway.

It also started beeping at me when I got out after shutting down and opening the door. It was a fast, non stop beeping that shut off when I closed the door. I guess it 'thought' I still had the car on?? Sometimes, if I restarted it and shut down again, it didn't beep. Not so the few days before it rolled over and died.

If Toyota wanted to be nice, they could put a message on the screen saying "The 12V battery is weak, consider replacing it soon".

In any case, from what I have seen on PriusChat, 4 years is about the time they start to fail. Might depend on your climate, I've not done any research to see if those in cold winter areas fail earlier than those in warmer climates.