I have a code reader now Using Dr Prius app it shows negative 12.9 v I’m battery block 24.9 block 3 with red indicator bars All other blocks are green
You are going to have to get the trouble codes in order to begin to knowcwhere to look for the problems that is causing that.
It really could be a number of things from simple to major.
Get yourself a code reader. It isca useful tool to have as a car owner, or go to a parts store or mechanic to have the codes read.
To just get the car starting again try disconnecting the 12v battery for a few minutes and reconnecting. That will reset ECUs.
Either way your going to have to read the codes in order to knowcwhats going on.