I have a 2007 Prius and everytime you go to start it the horn blows twice. It never did it when we first bought it. I called the dealer and they said it had something to do with the alarm settings. Does anyone know how to fix it?
How old is the 12V battery? Please check to make sure it is functional: Weird stuff happening? MPGs dropping? Test The Battery | PriusChat From the manual, it shows that the alarm system can go into "alarm sounding state" upon reconnection of the 12V battery. If the battery is bad, it might cause a transient glitch at startup which could do that also.
