Does anyone know what this noise is? It happens a few times for a few minutes after turning the car off. Posted via the PriusChat mobile app.
The rattle sound is from the brake actuator. Depress the brake pedal a few times while the Prius is READY which forces the brake actuator pump to run, and see if that is the same sound as the one you are asking about.
It’s just the Gen 2 doing it’s impression of the Millenium Falcon venting various hot gases shortly after it touched down on the landing pad of the cloud city on Bespin. Makes other puffing and hissing noise too, after you’re parked and walking away. Been doing it daily in almost 6 years of ownership! p.s. Yeah, what Patrick Wong said iPhone 6s +
Thanks guys. You were right! I hear it when I'm driving too. I didn't hear it before because I have my music on too loud when I drive. Oops! But the sound can be manually activated by depressing the brake pedal. Why would it do that while running (no foot on the brake) & when it's stopping & turned completely off? Do I have to tighten something up? Replace the brake actuator? Posted via the PriusChat mobile app.
Yes, that is indicative that the brake actuator is leaking hydraulic pressure which requires the motor to run more to keep the pressure up. You don't have to do anything until you see the skid control ECU warning lights appear: ABS/VSC/BRAKE/((!)) A new brake actuator is quite expensive so plan to spend around $1,500 or more if you rely upon dealer service. If you can buy a used unit and install it yourself then you'll be out only a few hundred $ - but this job is not easy. There are several posts about how to DIY if you are so inclined.
Yes, I am so inclined. I do all my own work. I'll wait for the service lights before I go tearing things apart. Thank you for insights in this matter! Posted via the PriusChat mobile app.
......D’oh!!! Aye, thank you. Apologies to Patrick Wong - duly corrected. That’s what you get for posting while half asleep at 4:30am BST. iPad ? Pro
Patrick Wong! You were right. It happened. All those warning lights are on & the brake pedal almost bottoms out. I happen to have a 2008 donor car for my 2005 daily driver. Posted via the PriusChat mobile app.
Also I've been trying to find the posts on replacing the brake actuator, but haven't had much luck. Could you please point me in the right direction? Thanks! Posted via the PriusChat mobile app.
The later post seems to confirm this original poster has the warning lights, and therefore does have a problem. But for others following along at home, just hearing a brake system self-test that happens a few minutes after powering off does not, by itself, indicate any problem. It self-tests because it cares. Sit around long enough in your just-powered-off Prius and you'll hear it every time. Or at least in a Gen 3 for sure. I know Gen 1 did not do such a post-power-off test, and Gen 2 I'm not positive about.
