For starters, I just replaced the 12v battery in my 08 prius for the 3rd time since mid 2015. Its a platinum battery from Advanced Auto Parts. I believe both times after the original went, the 2 previous battery replacements had dead cells when tested, which they told me cannot be caused by the car and is a battery issue. This time, I replaced it and the big triangle with exclamation point is on the dash lit up and the red outline car with an exclamation point is on the touch screen in the top left corner. The car seems to run fine though. It also seems the passenger airbag is staying off even thought the seat belt is triggered with nothing on the seat that should cause it to be. Weirdest part of it all, the car starts now with no key in it. The car started and I thought I dropped my key and it was inside (when testing the battery worked at first). Then when I got home I went outside of my car and tried locking it, it locked and unlocked fine with the smart key (meaning I did not drop it, it was in my bag the whole time). Then I left my bag 4 or so feet away from my car and tried turning my car on, and it started. No key inside at all (without a doubt). I will try again tomorrow with my key still in my house and I'll go out and try the car with it not even within 40 feet of the car and see what happens. What could cause the car to start with no key and show these warning lights after a battery replacement?
The red car with ! icon shows that the car has a problem with the hybrid vehicle system. You need to have the diagnostic trouble codes read. Regarding the car starting without a fob in it: how many fobs came with the car when you bought it, and are you sure that none remain in the car?
