Braking problem

[qbee42]

Originally Posted by tumbleweed

If you are right and this is not going to result in a loss of braking or occur at higher speed I can live with it. But as Basspro said it is pretty frightening. I think I have some idea when it might occur now and hopefully I will be prepared for it next time. I do think it is something that shouldn't happen, if it is a normal operating variance then it shouldn't be. My brakes should be predictable, of course the adrenalin rush was kind of thrilling.

You have no choice but to live with it. It's either that or sell the car. There isn't something broken on your car that can be fixed. This is just the way the Prius was designed. Perhaps a future upgrade could change the behavior, but don't hold your breath.

Tom

[tumbleweed]

Originally Posted by qbee42

You have no choice but to live with it. It's either that or sell the car. There isn't something broken on your car that can be fixed. This is just the way the Prius was designed. Perhaps a future upgrade could change the behavior, but don't hold your breath.

Tom

Yes, thank you, I understand it is a design problem and not a defective component. I suppose if there were an easy inexpensive fix they would have implemented it by now. I certainly have no intention of selling the car over this, I am growing quite fond of it after only a week of ownership. But as I stated previously it is a real shock when it first happens and I lost some confidence in the braking system.

[2010-V]

Originally Posted by 2010-V

Has anyone, with a 2010-V ATP, experienced a forward lunge while driving and braking when navigating over a bumpy road or pot hole in the economy mode? This happens every time I brake while on an uneven surface, not just occasionally. My first thought was that it may be related to the anti lock braking system, however, I am not braking hard when this happens.

This is a very scary experience, fortunately for me this has occurred when there have been no other vehicles, bikes or pedestrians in front of me. The car lunges about two to three feet and regains composure when it hits a smooth or even surface.

Any suggestions or should I schedule a service appointment today?

I thank everyone for your input and advice. I am somewhat relieved to know that the problem I posted is not uncommon and that others have reacted similarly to this phenomenon.

[qbee42]

Originally Posted by tumbleweed

Yes, thank you, I understand it is a design problem and not a defective component. I suppose if there were an easy inexpensive fix they would have implemented it by now. I certainly have no intention of selling the car over this, I am growing quite fond of it after only a week of ownership. But as I stated previously it is a real shock when it first happens and I lost some confidence in the braking system.

It is a shock when it happens, but let me tell you from experience, the Prius brakes really work when you need them. If you mash down the brake pedal, you are going to stop right now. I just about put myself through the windshield the first time a deer ran out in front of my Prius. Wow does it stop. Brake assist is a wonderful thing.

Tom

[tumbleweed]

Originally Posted by qbee42

It is a shock when it happens, but let me tell you from experience, the Prius brakes really work when you need them. If you mash down the brake pedal, you are going to stop right now. I just about put myself through the windshield the first time a deer ran out in front of my Prius. Wow does it stop. Brake assist is a wonderful thing.

Tom

Very good to know, thanks Tom. I am going to test mine but I want to put some more miles on them first.

[cossie1600]

It's a very annoying problem, you just have to mash the pedal and hang on. I would be curious to see if the 2nd gen did this

[hobbit]

This behavior is one more reason to make your stopping events
as long and even as you can -- in other words, plan early. You
get the best benefit of regen and least energy loss in the
electrical system that way, too -- less pack heating, less
chance of exceeding the current limit. The behavior over bumps
is simply the system protecting itself against excess battery
currents, and its recourse is to fall to hydraulics.
.
Most people within Toyota will likely have little idea how the
braking system works, let alone subtleties like this. Time has
proven that it's up to the owner community to maintain the info
and reassurance on this, and try to make sure new drivers know
what's going on and how to moderate their driving habits in
beneficial ways to compensate for it.
.
_H*

[qbee42]

Originally Posted by cossie1600

It's a very annoying problem, you just have to mash the pedal and hang on. I would be curious to see if the 2nd gen did this

The Gen II does this. I have a 2006.

Tom

[BlackSpirit]

Hi,

I am a UK Prius driver having owned my gen3 Tspirit for just five days. Yesterday I experienced this problem when I was heading down a slight hill and applying light brake pressure. The car suddenly felt like it was accelerating and I instinctively hit my brakes hard to regain control. Someone on the Toyota owners forum pointed me to this thread and having read all the posts I'm glad to know it was not just my imagination that this happened. Co-incidently the air conditioning died at the same time. The fan runs, but is not cooling the air. I have it booked in with service next week and will also mention the braking problem.

I agree with most of you who have experienced it, that it is pretty scary when it happens.

[a priori]

Originally Posted by BlackSpirit

Co-incidently the air conditioning died at the same time. The fan runs, but is not cooling the air. I have it booked in with service next week and will also mention the braking problem.

This doesn't sound like anything associated with the main problem discussed in this thread. Perhaps you have had both issues, but I don't see that they are related in any way..