2004 Prius Won't Turn On

12v batteries don't last forever, it might be time to replace it after 6 years.

Can you remove it and take it into an auto parts shop and have them test/charge it for free?

 

there is a date code on top

 

Dag,

Toyota planned for this. There is an under hood jump point. (and it's shown in the owners manual just in case my description doesn't work).

They kind of assumed if the 12v battery was dead, you would need a jump, but the trunk would be unable to be operated.

Look under the red cover inside the fuse box. Connect your positive jump cable to the terminal under the red cover. That cable goes directly to the positive terminal of the battery. Then connect the negative jumper to any bare metal component on the car body.

Ta-da.....you've just done the same exact thing as connecting a jump pack to the battery in the trunk, except you didn't need to be a contortionist. now you should be able to just open the trunk like normal.

 

The car should run even with the battery removed (once the car has been started, of course), so something else is going on here,

You may indeed need a new battery, but that can easily be worked out by testing.

Good luck with finding the problem here.

 

Are you saying, that the car was running, but as soon as the timer shut down, the car went totally 'dead'? If so, it could point to a number of issues. It is worth getting the battery tested (the 12v battery), but if the car is shutting down (when it is properly started up), there could be something else wrong. It is worth getting the 12v battery tested, in case it is 'shorted', and pulling the voltage down so low that the car's computers are crashing (the microcontrollers used have a low-voltage interrupt that causes a 'reboot' of the computers if voltage drops too low, which would cause the car to immediately shut down if the 12v battery was dead at that stage).