Brake pedal won't depress

Good to know such warning exists, thanks!
Of course I meant the pump sound I am familiar with for a decade.

 

Just make clear, no attempt to start the car during this test?

Then you could start the car?

Now that there is a way to replicate the problem and while it is under warranty, time to find out:

Bob Wilson

 

. . .

 

That's scary... Sorry to hear that. I'm curious to know if stiff brake thing is correlated to the problem...

 

that's your pedestrian warning system.

 

Yes this is the same for me, but isn’t a problem when I’m driving.

On the other hand. I do think that the brake pedal “feel” in this car is terrible. You can’t tell when friction brakes are engaging vs regen. And the brake assist is just as annoying in this car as it was with the gen 2. It almost makes it feel as if there are two brake systems. One that is extremely aggressive if you press the brake pedal slightly quicker than normal. And the other normal pedal feel is really slow and numb.

 

You know repairs can be expensive and this complex car is a huge unknown.
We understand and realize education takes time.

 

I'm feeling better now, too! I usually try to avoid becoming an early tester, but I couldn't wait for another year this time.
So your problem could be my problem.

Happy driving!

 

I think this is normal and I’m pretty sure my car behaves the same way. Drive any car with power brakes. When the car is off, the pedal is hard and high. When you start the car and the vacuum boost kicks in, the pedal lowers and becomes softer.

 

The Prius does not use engine vacuum boost though.

 

As I understand it, it has a electric vacuum (or pressure maybe) accumulator. Basically functions the same in that it provides power boost to the brakes. No electric power, no boost.


iPhone ? Pro

 

It's already been explained before, though, not just elsewhere on PriusChat, but at least twice above in this thread: the pressure accumulator, when topped off by the electric pump, normally holds usable pressure for many hours, or for about 30 strokes of the brake pedal, which is what you normally need in a Gen 1 or Gen 3 Prius after shutting the power off, before the pedal becomes hard. (Gen 2 worked a different way.) Usually you can exhaust the vacuum in a conventional car's power brakes in 2 or 3 strokes if the engine's not running.

There seems to be one open question whether Gen 4 or Prime may have added an extra valve that blocks off the boost pressure when "asleep", which will eventually get answered yes or no by someone with an active techinfo subscription. But otherwise, the norm for the Prius is that the boost remains usable for a good long time.

-Chap

 

pleasure.

 

I have been having the same issue with my 2018 Corolla. The brake wont depress and the car won't start. I have push button start. This has happened 3 times. Dealership cant reproduce the problem so they dont know what is happening. This last time is when I actually realized that when the car won't start the brake pedal is not depressing so hopefully they will be able to determine the culprit and fix it. Wish me luck. She is at dealership as we speak.

 

all the best!

 

If it's the same problem as in the Prime, to reproduce the problem try sitting in the car for a few minutes without starting it or touching the brake or anything. The brake pedal should feel hard after that if it's the same issue people here are having.

To fix it, try getting out and getting back in. Getting in (Specifically, I think opening the driver's door) triggers the brake pump in the Prime. You might hear a slight buzzing or humming if it's running.

It should still be possible to start the car by pressing hard on the brake. Put some weight into it, you won't damage anything. Once it starts the brake pump should run and the pedal will immediately become normal.

I always assumed this problem was weirdness caused by the fact that we have regen braking. But maybe it's more related to the fact that these cars can automatically control the brakes for dynamic cruise control. Or maybe it's a defect?