Ever since we got our '05 Prius, it has “barked”. The “bark” sounds like a quick burst of the horn: Very short and not very loud. It only happens in cold weather, when the car is slowing, or you depress the brake while stopped. It is, however, by no means regular. Those reqs may be true, but it doesn’t happen every time. We aren’t particularly concerned about it, another Prius owner we know has a Prius that does exactly the same thing. We are more curious about what it is.
I Think Toyota Is Aware Of This.
I can’t just tell you to ignore it. You should have a Toyota dealer or independent Toyota mechanic check your brakes. Then you can probably ignore it.
Toyota issued a Toyota TSB (Technical Service Bulletin) pertaining to 2004-2007 Prius brake system noise. They say a noise is barely audible when pressing or releasing the brake pedal and sometimes can only be heard when stopped.
They were replacing the brake actuator for complaining customers during the 36/36 warranty.
If this is what makes the sound in your car, it may only be a minor incovenience rather than a safety issue. Brake performance may not be affected by it.
However, get it checked to be sure. Your local dealer should know what you’re talking about. Perhaps just a test drive will do.