I just bought a 2010 Prius III and when I put my hand on the driver's side door handle to open it I hear this mechanical vibration sound that is somewhat loud and long in duration coming from under the hood. The door unlocks and opens fine but I'm wondering what the sound coming from under the hood is and if it is normal? I noticed when I open the door again to get out I hear a similar sound but it doesn't last as long.
Someone mentioned in another thread that when you open the driver's door you hear that sound - something to do with getting the brakes ready. The Prius, my '08 Highlander Hybrid, and the '07 Camry Hybrid all made that sound, as I recall. Watch the DVD that came with the owners manuals; it'll explain the strange sounds of a hybrid vehicle.
So does the manual, section 1.1: n [FONT=Arial,Arial][FONT=Arial,Arial]Sounds and vibrations specific to a hybrid vehicle [/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]There may be no engine sounds or vibration even though the vehicle is able to move. Always push the "P" position switch when parked. The following sounds or vibrations may occur when the hybrid system is operating, and are not a malfunction. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]Motor sounds may be heard from the engine compartment. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]Sounds may be heard from the hybrid battery (traction battery) behind the rear seat when the hybrid system starts or stops. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]Sounds from the hybrid system may be heard when the back door is open. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]Sounds may be heard from the transmission when the gasoline engine starts or stops, when driving at low speeds, or during idling. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]Engine sounds may be heard when accelerating sharply. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]Sounds may be heard due to regenerative brake when you press the brake pedal or release the accelerator pedal. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]Vibration may be felt when the gasoline engine starts or stops. [/FONT][/FONT] l [FONT=Arial,Arial][FONT=Arial,Arial]You may hear cooling fan sounds coming from the air intake vents behind the rear seat. [/FONT][/FONT]
Thanks for the suggestions. I did read that part of the manual but all of the bullets seemed to indicate sounds that would occur while the car was actually running. I will watch the DVD too and see if it explains it any better.
On page 153 of my manual it says, "Brake Actuator: In the following conditions you may hear a sound in the engine compartment. This is not a malfunction. - the drivers door is opened with the hybrid system off"
It's the 12V power brake electric pump getting the pressure up to give you assisted brakes even before you power up the car. You can also hear it do its job if you pump the brakes at any time (even with the car off).