do your prii make a spooling / ticking noise sometimes when you are braking or slowing down? it seems to come from the front of the driver side. is this normal? I'm not sure how to describe the sound, but there is definitely a sound (sometimes).
Maybe pshady is refering to the sound I've also noticed coming from under the dashboard. It happens sometimes when I'm driving, but also sometimes when I press on the brake before turning the car on. I assumed that it was from the device connected to the brake pedal that controls regen. The car makes so many interesting sounds when it boots up or shuts down that I didn't really give it much thought. Maybe some ambitious person with a portable recorder could post some wav files of the various normal sounds the Prius makes. Things like the coolant pump, or the ticking sound from under the dash.
Shady, you are not insane!! OK, maybe you are insane, but if you are, you have company! The noise you are referring to does happen when you brake and is very noticable in my Prius. I've never taken the time to figure out exactly what it is, but I'm pretty sure it has to do with the car either going into regenerative breaking or from regenerative breaking to physical breaking. It seems to be much more noticable during hard breaking. Ever notice all of the switches closing and opening when you power up or power down the car? Always reminds me of the beginninng of the Animusic CD (www.animusic.com) where the instruments are powering up.
that is a regen braking... i never would describe it as a ticking sound thou, although the sound of a jet winding down is a very good description.
The other noise you could be hearing is the hydraulic boost pump which provides the power brake presure. It consists of a whirring which drops in tone as presure increases, then followed by a click of the relay that turns the pump off (probably pressure activated).
No ticking but "whirring" or "humming" I have always assumed it was regenerative breaking. I am light on the breaks, I have not been "on" the breaks yet. It really sound like a electric motor spinning to me, but what do I know. We need the monitor thingie. We need to know this stuff.
The sound that I'm curious about could be described as a ticking, or possibly a ratcheting sound. It occurs when you press on the brake pedal, and sometimes can be heard when you press down on the pedal before turning on the hybrid system. This is totally separate from the sound that the motor/generators are making during regen. That sound can be best described as a whir, whine, or a jet engine.
if you push hard enough, sometimes you might hear the anti lock mechanism going off, but that would be rare i would think. the anti lock system cycles on an off real fast and you might hear a clicking sound for a second at the most once in a while... (when moving you would never hear it, only when stopped) but you should not be pushing on the brake pedal that hard. it isnt necessary and i dont think it is good for your car. the only way i found out about it was because i was sitting a light and stretched and pushed hard enough to set it off.
Maybe this is a change with the later '04s. Normal depression of the brake pedal before pressing the power button results in a ticking or ratcheting sound from under the dashboard. It doesn't sound abnormal to me, and I assumed that it had something to do with brake pedal positioning to determine regen rate.
I agree with vapor_pearl, it is like a ticking or ratcheting. i have heard this sound MANY times and wondered what it was. As it happens when the car is not in motion, I doubt it is a regenerative braking action, but it could be related to the motor used as a generator during the regen braking. It is hard to see why pressing on a brake pedal in a stationary car would make a motor spin up to speed though, isn't it?
Yes, this is what makes it such a strange sound!!! As vapor_pearl said Note this is BEFORE pressing the power button. Same on mine.
Don't think it is related to newer Prii. My Prius is in the 15K serial number range (bought it in Dec 2003) and I hear the "ticking" clear as day most times I press the brakes.
