Gen 2: Death Triangle Sign

there is no indication of dying battery when it first sets the warning. it's a notification to do something before it is too late and you're stranded somewhere.
P0AA6
p0aa6-hybrid-battery-voltage-system-isolation-fault-car-does-not-start.199004
you'll probably need a reader or the sub code, but you can try opening the battery case and looking for corrosion, that's a common problem.

 

You'll need the subcode but most of the time this nonsense is inside the HV battery case before I wait for a scanner or do any of that I'm already looking in the battery tray just because I can't help myself with a cheap scanner that doesn't necessarily read all the codes of your car something just laying around plug it into your port let it read the codes If it just flashes and says there are none clear the codes with that cheap scanner two times in a row even if it says there are no codes hit the clear button and it'll tell you codes have been cleared. Now push the button again says the same thing but your car will start right. Usually the isolation fault is the acid in the cells inside of the module has leaked out from somewhere on the prismatic assembly. Usually when you undo the rods and break the pack apart You can see in between the aluminum pieces that bond together when they're squeezed and you'll see what was leaking looking at the bottom of the tray you can see where it's dripping between two modules they'll be several of those and usually six or seven modules are involved because they're done in pairs when they're leaking they're leaking between two I replace both of them don't want to have to gas or any of that.