I was driving with a frien that has an '08. Once while stopping we heard a very faint 1sec beep from the back. He said it happens every once in a while and his kids hear it better from the back seats. Any ideas on what it is? I have never heard this from my '10
His kids probably lost a small electronic toy somewhere in the hatch area. If he is serious about locating the sound, he will remove the rear seat cushion, the hatch folding floor and other hatch trim, and look around for the noise maker.
LOL. it's definitly not a toy. It sounded like a battery type noise and the kids aren't the toys in the car type.
Consider the factory-installed items in the back of the car that have moving parts and might produce a noise: - traction battery fan, which would make a whirring sound - system main relays in the traction battery enclosure, which make a click sound upon making the car READY and IG-OFF If items like toys, cell phones, etc are ruled out then is it possible that some dealer-installed accessory like an alarm or backup sensor system might be producing the noise?
It is really strange. I was driving with him all week (lots of trips to home depot for his kitchen remodel) and heard it only twice. It is definitely an electronic type sound and only when braking. I was thinking of something like the regen braking was making it under certain situations but seeing as nobody else is familiar with it then I just don't know. We ruled out any non Prius stuff in the back and it doesn't sound like its in the cabin anyway.
