I have a 2008 Prius. I noticed that a large red triangle displayed briefly on the left when I started my car the other day. I know all the other smaller icons light up briefly but I don't remember the large red triangle lighting up. It and all the other icons go off after a second or two. Then the next time I started the car there was no red triangle. Then maybe the 3rd time I started the car, the large red triangle did again appear briefly. I took my car to my Toyota dealership but the tech said that is normal and means a door must be open, but that cannot be correct. I make sure all doors are closed and the "Open door" icon is not showing. I have already been through the water coolant inverter pump disaster so I admit I am a little paranoid about any funny things showing on my dash. Any ideas? Please don't ask me about codes or any highly technical info. Thanks so much.