Discharged Prius

That's too bad your wife had to experiance that. You might want to check the center console. Ever throw coins in their? it's possible for something to have shorted out the 12V plug.. have them checked.. those little plugs are not perfect.. they do get flaws every once and a while. When they do your diagnostics, they should have checked the current draw when the car is off. They should be able to tell you right away what's wrong, if they do that.

I agree to have the battery checked. Little tiny battery. If somehow it was drained before for some reason.. it's weakened now. I get the feeling Toyota didn't do a very good diagnostics job. They probably plugged in to the computer to see what it said. Not everything is computer. Some things have to be done by hand.

 

Even if you were to turn the car on to lower the windows.. when you turn the car back off.. the lights might turn on in the inside.. but they would go back out after about 10 seconds or so. This should not have drained your battery.

As for replacing the 12V.. no.. when you took it to the dealer ( which i would be guessing to be soon after it happened) they would recharge it and it should be fine. They would know if it's bad.. or.. they should know.. some dealers aren't too bright sometimes. As long as the car is starting up.. it's probably fine.

I was just thinking about the ACC.. and IGN ON modes... ACC is first right? can you do the windows with this?... what if she turned everything off.. when in ACC mode.. and rolled the windows down.. pressed the pwer again which sent it into IG-On.. now.. the hybrid system will not work.. but the system is still sucking energy.. a couple hours of this might drain it.

Either way.. it's a guessing game. Just make sure she knows about the power modes.. and that the engine can only turn on when the car is actualy on ( brake + Power button )... you can rest like this.. you may burn up some fuel if your battery gets low.. but only if you have the AC on.. if not, then you should be able to listen to just the radio for quite a while.

 

I wish you could ask the car.. hehe.. o well.. good luck with it. It is possible that the headlights turned on when she rolled the windows down.. and then stay on.. but i don't know how long they would stay on for.. either way.. goodluck.. let us know how your test come out.. i'll repeat your test for you if you like.. just to test a different habbit when it comes to driving.

 

Could her foot been on the brake turning on the brake lights. I remember napping in a similar situation only to have some knock on the window to tell me to move my foot or my battery might go dead. Doesn't take much pressure to engage the light in most cars. Just a thought.

 

He said she crawled in back, so I would guess that means she wasn't sitting in the driver's seat. I find it interesting that this could happen. If there was enough power to show a dim "Engine Malfunction" warning, why would that not be enough to start the car since 'start' means powering up the computer, not cranking a starter motor. Or does the little 12V have to do more than that?
Yet another example of why Toyota should at least have a switch that allows you to 1) charge the 12V from the traction battery or 2) start the car from the traction battery so the ICE can recharge the 12V

 

I'm suprised it did not start up.. but a few circuits will require at least a little bit of stable power. As for charging the 12V.. once the car "start" the hybrid battery will charge the 12V.. it's programmed to keep it charged when the car is on.