So we just got our 2010 today. My friend has a 2008. When he starts his 2008 and drives away it is almost silent. Standing outside the new prius I noticed when my wife started our 2010 and i was standing outside there was a loud electrical type HUMMMMM sound. It about as loud as a radio playing - i mean you can really hear it. Kinda like what a power transformer sounds like. From inside the car you can only slightly hear it. Car seems to be running normally. Is this normal? Or do we have a problem?
I would guess this is your (gas) engine kicking on to charge the battery and warm up the engine for optimal driving. Does it start right away after you start the car or kick in after a bit? Does it stop after a bit if the car is just sitting there? If it's not this, then no, I don't think that's normal, other than the above mine is so quiet that someone like me used to driving old cars keeps thinking it's died. Where is it coming from? Under the hood?
No its not the gas engine. This sounds very electrical. Starts the instant the car is started and is not moving. Comes from under the hood. Closest thing i can think of is the sound you sometimes hear of a bad transformer up on a power pole. Like electricity vibrating/humming if that makes any sense. It is not subtle, it is fairly loud on the outside of the car. If you are inside the car it is not too noticeable unless you are listening for it then you can hear it.
Hmmm, ok (and hope you didn't think I was insulting your intelligence, wasn't sure how familiar you were with the Prius; I wasn't before two weeks ago or so and have had to get used to various things). Well, that doesn't sound normal to me. Maybe some of the more knowledgeable types on here can comment, but I'd say take it back to the dealer if you are concerned, and it sounds like you are, and I would be.
if I am not mistaken, it has something to do with the charging of the braking system. I remember something about it in another forum, but dont remember where it was. But what I do remember, I believe it is the braking system either charging or cycling, or something like that.
