DEAD BATTERY - LEFT SITTING SINCE JAN 2014 HELP!!

it's most likely the 12v. it's hard to say on the big battery because you need to fire up the computers to find out. is the 12v original? if so, just replace it. grab one at toyota or auto zone or somewhere, they are easy to change. make sure it reads 13v before installing or it might need a charge.

 

Most likely it's just the 12V battery that's dead.
It's also likely that the 12V won't hold a charge after sitting flat like that.

The car will act strange with a failing 12V battery but carefully boosting the 12V from another vehicle can help you determine if the big battery is healthy enough to start the car.

 

Remove the 12v and take it to an auto parts store that can do a free "load test" on it. This will tell you if it needs replacing or simply recharging. Most likely needs replacing.

 

If big battery doesn’t have enough charge to start engine it’s probably enough just to slowly charge it with grid charger.

 

Our 2010 has a build date of August 2009, and we bought it, with maybe 6 km's on the odometer, in November 2010. The 12 volt was toast, the dealership conceded it*, put in a fresh one. But the hybrid battery has been just fine, nothing untowards, to date.

* The dealership first tried every trick under the sun to dodge 12 volt replacement, it was pretty pathetic. When we first showed up to test drive it, they had it in ready mode, basically on. I'm sure they'd been jump starting it behind the scenes. After the drive we went back in, then in the discussion, something came up that required going back out and starting the car again...

 

I will help you to fix it. If you live in los Angeles. 3233502278. I am getting divorced and I know what it is. I won't charge you.