When you open the drivers door, it is like a 2-3 second whirring sound that seems to be from under the dash.
http://priuschat.com/forums/gen-iii-2010-prius-main-forum/64983-hydraulic-sound.html http://priuschat.com/forums/gen-iii...omething-happens-when-i-open-driver-door.html http://priuschat.com/forums/gen-iii...-hood-sounds-when-using-smart-key-system.html
Me either, but I read the posts recently, and got lucky finding them just searching on "door + sound." I found them informative, and figured others would too.