Hey Priuschat, I purchased my brand new 2015 Prius four (w/ solar roof package) this past Thursday. I am loving it so far but since this is my first hybrid I am not accustomed to some the sounds it makes. I have found quite a few threads regarding weird noises but in my circumstance it is different. As the title suggests, I frequently hear a whirring noise. It sounds entirely normal (in a sense that it doesn't sound like something is broken), what bothers me is how frequently I hear it: Whenever I open the driver side door, often when I depress the brake pedal (I'm not sure if it does it while driving, too much wind and road noise, but I have heard it when braking in EV mode). It just seems to happen too often and its stressing me out. I'm thinking its the brake accumulator because that is what I read is the source of this noise. It drives great and does not seem to cause any issues. What do you guys think?
I was gonna reply the same but I don't get the "whirling sound when he opens the door" though? Maybe the SKS?
You get that sound every morning (or when it sits for a while).......1 time when you open the driver's door. The prius has electronic brakes, that's what you're hearing. You don't hear this on a regular car because it doesn't have hybrid synergy drive.
Ah well that makes sense. I went through the owner's manual and the included DVD, both had sections discussing 'sounds common in a hybrid' none of which were the sound I was hearing. Upon further searching I did find some threads that discuss other owners experiencing precisely what I am and the consensus is that it's the brake pressure accumulator pump. Thanks for your help!
Bit of an oversight on Toyota's part perhaps but considering they made the effort to discuss 'hybrid noises' you'd think they'd cover them all.
Regular cars use manifold vacuum from the continuously running engine to power the brake booster. The Prius doesn't have a continuously running engine, and usually not much vacuum differential even when the engine is running, so needs another source. So a 12V pump pressurizes a reservoir.
