I'm a newbie to owning a Prius and I've had it only a few months. The 12V battery died so my mechanic put in a new one YESTERDAY. It ran fine on the way home, showed fully charged. Got up this morning and it wouldn't start. I wasn't able to unlock with the smart key, but the engine light came on and the power button turned from green to red. HELP!
welcome! how do you know it's charged? the meter on the dash is for the hybrid drive battery, not the 12v how many miles on her? if the engine light came on, you need to have the trouble codes read
Try starting the car with the keyfob inserted into the dash slot. You might just have a bad keyfob battery
How did the 12v "show fully charged"? What visual aid did you use to come to that conclusion, because there isn't one in the Prius. The absolute best you can do is look at the textual output of the voltage on a diagnostic screen, or read it back via the OBDII port and as anyone will tell you, voltage on a lead acid battery will not tell you state of charge. It is also very common for brand new 12v batteries to be nearly fully discharged when pulled off the shelf. They were manufactured a year ago, sat on a shelf in some warehouse draining, was bought by a local distributor, sat on a shelf, then you bought it.
I was told by a mechanic that the code read as the 12V being fully charged. I'm not really sure he knew what he was talking about either. I took it to a new place under warranty to get the battery checked again. I assume the battery they gave me is not good.
