2005 Prius was dead this morning. I had left a light on a couple of days ago and had to jump it. It started right up. I only drove short distances in the next couple of days, so I thought battery hadn't charged fully. But when I tried to jump it this am it was to no avail. Took battery out and had it charged at parts store, reinstalled and still nothing.. Is it the BIG battery? Or what could it be? I pushed start button twice without foot on brake;it just flashed some symbol quickly, nothing more.
Why not have your foot on the brake while pushing the power button? If the 12V is bad, it will not hold a charge. It could have left the parts store at 13V and arrived at your house at 10V -- that is the scenario for a dead cell. The gold standard is using a multimeter at the terminals to measure the voltage, as well as measuring the resistance from the negative post to the chassis. If you have 12.4V and less than 1 ohm resistance to ground, then the problem is not the 12V.
One post said to hit power button twice with foot off brake to get some screen telling you info but it didn't do anything with or without foot on brake.
If you don't have a digital multimeter available, just turn on the headlights and see how bright they are. If dim then you will know the 12V battery is bad and needs to be replaced.
