My 07 Prius was left off for about 5 days and it would not start. When I finally jumped it I got the Triangle of death and a stop warning. I changed the 12V battery today at Toyota as it had not been changed for years. The car has been driving normally and the Dr. Prius App says the battery charging is relatively healthy. I am hearing a lot of talk about it being the inverter but I can't imagine that it's failed considering the car has 65k miles on it. Has anyone dealt with this? I also keep seeing that it might be the inverter pump? Any thoughts? Car starts up fine.
If P0A09 is the trouble code, then the approach that will get you straightest to a solution will be to look in the repair manual under P0A09 for its "detection condition" (which tells you what the code in fact means), and for the troubleshooting steps that follow, which are how you can sort through the different possibilities for what caused it. Toyota Service Information and Where To Find It | PriusChat