I have a 2014 Prius c at 22,000 miles, and it just recently started beeping every minute or so. It sounds like it's coming from the center console, but it's difficult to assess. Has anyone ever had this issue? It's become quite an annoyance. No maintainence light is coming on or anything like that.
From the experience I've had with my C, I usually get a beep when I'm low on fuel, or for a seatbelt warning. I doubt it's your fuel as you'd be stuck in the road constantly, so I would say check for any seatbelt indicators on your dash. Any sort of heavy weight can trigger the driver or passenger seatbelt if the vehicle is in motion at speeds of 13mph or more. If that's the case, then it might be a faulty seat/seatbelt sensor.
Did you may be leave a door open or leave your parking brake on while moving? I can't think of anything else...
