Well, I got there late to pick up my rig, and the tech was gone. Note on the invoice said the noise was a normal function of the brakes. No more given. I've had the car for one week, and the noise just became noticable three days ago. Will monitor and report if I can learn more. Cheers,
Before you power up the car, press the brake pedal 3 times firmly. On the second or third press you will hear the brake charge pump pressure up the accumulator which is the equivelent of the old vacume booster on normal car power brakes. Well the Prius isn't a nomal car, and because the ICE will quit running in normal operation the brakes need some other form of power assist hence the hydraulic power assist and an electric powered pump to keep the pressure up. Hope this helps explain what and why your hearing the noise.
