I hear a long beep (not exceptionally long) when I press the power button to turn my Prime on. I don’t know how to begin looking this up. There isn’t an accompanying message on the screen. Can anyone tell me what this is?
Mine makes a brief beep when I put it in READY if the seatbelt is fastened before I start the car. W/O the seat belt, it chimes repeatedly. If you don't have a PDF version of your manual, they are free to download from the Owners' page at toyota.com. Once you have the PDF, search for the word "buzzer." It's on 59 pages in my manual, so it'll take some time to peruse them all.
Does it always do that ? Any chance that you are pushing the "start" button before all the doors are closed ??