Brake assist experience

Very odd. It sounds just like what happened twice to me only I was backing very slowly. How fast were you going?
What is the build date of your Prius? Has the update been done?

 

Interesting! I have the same questions as Spiderman, do you have the update? and when was your car built?

I have not had the update (recall) and my brake pedal seems to require the same amount of force all the way from the top to the pedal stop near the floor. The amount of brake applied is a function of the pedal position rather than the amount of force applied. I have gotten used to that feel and kind of like it, which is why I have not had the update done. I have never had the experience you describe.

I think, however, that the brake issue that initiated the recall is quite similar to what you describe. I did feel that about 3 times but always on slippery surfaces and it seemed to be a delay between normal and ABS braking. In spite the fact I have not had the updated firmware installed I have not experienced that issue for at least 5 months and 10K miles now.

 

Tom,

I have had the brake update and my pedal still feels like it did before with the brake force relating to pedal position and not force.

Dwight

 

That being true maybe I should go ahead and have it done. Can you still push the brake pedal clear down to the pedal stop with the car stopped?

 

Tom,

I have never had the need to try it but will tonight. With a reasonable amount of pressure on the brake pedal at a stop light the pedal is still well above the floor, with what I would consider as a normal amount of resistance.

Even when I have had to brake hard my pedal has never come close to going all of the way to the floor.

Dwight

 

Brake Assist activates when you *rapidly* remove your foot from the accelerator and slam on the brakes. In this situation the Prius assumes you are making a panic stop, and increases braking in anticipation of that.

The situation you describe does not sound like a panic stop, therefor Brake Assist should not have activated. Likewise the brake pedal feel does not change when Brake Assist activates.

Tom

 

I hope this video could help you (brakes part in the final)
Brakes are working good since the upgrade was done.

YouTube - Prius 2010 MAX MPG Secrets

 

I'm guessing that it did that the other day when I had to bring the car to an abrupt stop so that I didn't end up killing bambi. Dadgum deer jumped the guard-rail and ran across the road right in front of me as I was going around an on-ramp to get on the highway. Almost had a fresh serving of steering wheel for dinner, because I didn't have time to even brace myself for it. It did kind of sound like the car made an odd noise when I stopped, but maybe it was ABS doing its thing and just the tires "skipping" briefly. I'm just glad no one was behind me!

 

Just an observation on the 2010 brakes. They are a poor substitute for the 2005 Prius brakes we were used to. We've had the update, which, of course, did nothing to help the normal braking power. We don't feel as safe in the 2010 when braking after having the instant braking response of the Gen. II.

 

The brake can be depressed as far as you want whenever you want as many times as you want. If the car is off you'll hear a pump or accumulator click. Pushing it all the way down engages Hill Start Assist.

 

What if he has a Pv w/ATP, I bet the breaks would apply full force if radar is not happy. Review video notice car to the right at 37 seconds coming on to freeway. Activate collision avoidance.

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Was it wet, and were you transitioning down through about 8 MPH
from regen to hydraulic? You could have had the sandpaper problem.
.
_H*

 

Coming from cars without Brake Assist, I've found the 2010 Brake Assist to be D*** Fast. Especially when I don't need it.

And once, when the car in front of me suddenly stopped in the middle of the street with no functioning brake lights at the worst possible moment of my eye scan sequence of the surrounding environment, I was glad to be in this Prius. My other car would have had little margin. Prius stopped with a large margin.

The car behind had almost zero margin. My brake foot has since been recalibrated.

 

When my episode occurred (hit a sharp ridge of ice just before a crosswalk)at about 15mph), the pedal sank to the floor with little or no back pressure, lights came on the dash (not sure which ones) and chime went off twice I think. Also, the accumulator pump came on. To me, it was almost like pressure failure in the system triggered by hit.
Did you have any warning lights come on?

 

My Pruis has the best brakes of any car I've driven in 33 years and in that time, I've driven a lot of cars. For a time I was renting cars on a weekly basis for work and I doubt any of them would have stopped faster than the Prius.