Brake "Honking" Noise - Bad Actuator Help please

Unfortunately, the noise is almost normal.
It may go a long time without any problems.
You could try changing the fluid to see if that helps

 

There is a warranty extension for this. Did they even mention it? Ask them, mention you'll check with Toyota too, that might help.

I'm not sure what the criteria and time/mile limits are, doubly so in the States, but there IS an extension. If the dealership didn't at least mention it that sounds pretty slack...

For me in Canada it's for sure 10 years since purchase date. There's km's factor too, but I'm way under it.

 

Mine is doing the same thing, should i just use it has it is? no lights in the dash. I think i will just wait until the dash shows that the thing is no more.

 

What could be causing such sound? air in the system or something else?

I live in a quite high place, since when i'm leaving my house to go shopping or something i can feel that my ears clog, so i guess it's a decent altitude. My Prius C 2012 is doing those honking noises as well, it could be the altitude maybe?

 

Well, the original poster had a 2011, and for 2010 and 2011 Prii there was a firmware update described in T-SB-0363-10. When mine was making that noise some I asked the dealer to update that firmware and it helped.

If somebody has a newer Prius, or checks their brake firmware revision and it's already the updated version in the TSB, then something else could be going on.

I don't think I would choose to put up with it for very long. I suspect (though I have done no experiment that really confirms it) that gas bubbles in the brake system are involved, which increases the amount of brake fluid flow needed to reach a certain pressure, and that the honk is some valve in the actuator being played like a saxophone reed by the fluid squirting past. If I'm right, going through the long-form bleed procedure might well help, for some time at least.

It seems Prius brakes can kind of manage to work even with amounts of gas needing bled that would be enough to disable braking in a conventional brake system. So a person could get sort of complacent. An argument against complacency might be that Prius brakes also have a fail-safe mode they can drop into if the electronics mess up, and the fail-safe mode more or less is a conventional brake system, and if there's enough gas in there to disable a conventional brake system. having it ever drop into fail-safe mode would come with an unwanted surprise.