My 2011 Prius II hasn't had any issue for the 3 years I've had it until two days ago when the car simply wouldn't turn on. The battery would "whirl" when I would press on the brakes but when I pushed to power button nothing would happen and the Ready light would never come on. The power button didn't have any color (orange/green). The batteries were charged and would spark when cables were connected to them. I tried it again about an hour later and it worked fine. I drove it for a couple minutes and parked it hoping that it was a fluke. Another hour later I tried to start the car and the same problem as earlier happened. I decided to tow it to the nearest Toyota dealership to get it examined/fixed, but after they've had it for 2 days now they cannot get the car to reproduce the same symptoms. Has anyone else had issue like this? I've heard of batteries losing charge due to headlights/doors being left open, but that wasn't the case here. All of the car's components worked (headlights, brake lights, headlamps), it just wouldn't turn on.
some times, the brake switch needs to be adjusted. and it would still be a good idea to test the 12v battery, even though everything worked.
Test battery level with a volt meter, not with a 'spark test'. The presence of a spark doesn't provide a meaningful measurement of charge level (other than 'really dead' when absent), and the surge that goes along with the spark can be destructive to numerous electrical things.
The 12V battery could have one dead cell, meaning it would be a 10V battery. That is about the limit to get into "ready". Once there that cell would charge up enough to give 12V for awhile. Usually this is caused by sulphate in the cell built up on the bottom till it touches the plates. This causes the cell to slowly discharge (overnight, for example). So after getting the cell level back up you park and voila, next morning that cell is again dead, and you can't get to "ready". First thing in the morning, before trying to turn the car on, use a voltmeter and measure the 12V system voltage. You can do this at the "boost point" under the hood or at the battery. If it's 11V or lower you need a new 12V battery. 11.5V indicates a new battery will be needed soon. 12V +or- 0.2V is normal. Note that by the time the service shop sees the car, you have got it in "ready" and the dead cell will be partially charged, so they can't use the above method. Note further that instead of getting the car towed (too late for you but others reading this thread may benefit), you can boost the car from the boost point under the hood and drive it to the shop. You can use a remarkably small 12V battery to boost a Prius, as it doesn't power a starter motor. Even an emergency light battery (sealed lead acid 12V) will work. DO make -sure- you boost with the proper polarity. A mistake here would be costly! If you are not confident you can do this it will be much less expensive to get it towed!!
We actually did try to jump the car on the boost points on the front of the car. No response. Is there anything special you need to do when you jump from that point? (keep them on there a certain amount of time?)
The battery spark test can also result in a battery that explodes - very bad idea, be careful. Volt meter is your friend.
Having worked at a dealership and seen a battery explosion in person, I'm now much more careful around 12v batteries. Safety glasses are a must! Your skin can heal, but your eyes are not so resilient. SPH-L300 ?
