I have also experienced the Prius Brake Problem

Was there a valley in the road? I've been caught off guard a few times and couldn't figure out why it kept doing it (on a road I normally travel) until I inspected it closely. You really couldn't see it out of the car until you know what to look for.

 

that is something i noticed also.no bumps no pot holes just a sease of braking . odd! i already have about 4000 km on my taxi! it almost felt as if i eased of the brakes and then reaplied,but without doing that.it did it 2 times today!



but it didnt happen when trying to come to a full stop ,it happened while trying to slow down! both times!

 

I am still having the problem after the fix and am reporting every instance to NHTSA. Tried to work with Toyota and got nowhere. Looked on NHTSA today and there are dozens of complaints from people who, like me, are still having the problem after the fix. Very frustrated!

I know people will probably flame me for complaining (I have read many other posts and seen newbies like me destroyed with sarcastic remarks) about the problem, and Toyota keeps denying there is even an issue. I saw that someone said it is just normal for hybrids, but had my dealer told me I would have a delay in braking between the two systems, I would have passed on this car. I drive my two young children in this car and no longer feel safe doing so. BTW, I drove a Ford Escape hybrid and I did not have this problem.

 

1.) It's not a problem, it's the nature of the combination of regen braking and ABS operation. Since you've driven a Prius "under most all conditions" I figure you would be used to this sensation by now.

2.) HAHAHAHAHAHAHAHA "unintended acceleration" sure is scary in a Prius isn't it?

Please, join us in a place called reality where these "problems" don't exist and are nothing more then mass media mind control.

 

We (including myself) are naturally quite dismissive of complaints from low post count folks who haven't read up on known quirks/issues, some of which make claims that are simply untrue. claim the sky is falling, asserting safety issues, etc. It seems trolls and complainers w/the first post being a complaint randomly show up in waves... Most of which never return either. It's like tossing a grenade and running away.

There have been countless arguments in numerous other threads. If you have known repro locations of braking issues, (barring privacy issues) please post them in the form of Google Street View links. I posted a specific repro spot for my 2nd gen Prius at http://priuschat.com/forums/gen-iii...99-poll-prius-brakes-problem.html#post1031776. Bwilson4web likes collecting them.

But, in all seriousness, others near you can try to repro and it also gives specific repro cases, if Toyota wants/needs them. I've hit the quirk on my 2nd gen in numerous other places but it's so minor, it's not an isue (hence my answer in that post).

As Bwilson4web has discovered, many safety complaints to NHTSA are not actionable due to lack of sufficient information.

I work in software and for someone to effectively fix bugs, there needs to be a way to repro and debug the issue. What might be one bug/symptom might turn out to be actually several separate bugs, possibly all w/different root causes.

I wouldn't necessarily be so dismissive of nylion's claims. He had an unintended acceleration problem in a thread he started at http://priuschat.com/forums/gen-ii-...nintended-uncommanded-acceleration-issue.html long ago. He sold his 2nd gen Prius as a result but was willing to take a chance on a 3rd gen.

 

Two unintended acceleration episodes in two different cars that happened to the same person, but not everyone else who has either a Gen II or III? What's the chance of that happening? That's more reason to be dismissive of the OP's claim, not less. I bet it's something completely normal to the rest of us.

 

I have yet to see anyone say that they PUSHED THE BRAKE PEDAL HARDER AND THE PERCEPTION OF "NO BRAKES" PERSISTED.

If that happened to me, I would FREAK OUT. However, most of what I'm reading seems to be people who are in regen and don't push harder when the regen "lets loose." I've certainly felt that many times, and take FOR GRANTED now. IT'S HOW THE CAR IS SUPPOSED TO WORK.

Now, if there is a genuine DEAD PEDAL that's two seconds, where jamming on the brakes doesn't work, that's another issue, but I've not found anyone say that's happened to them.

 

I understand why you might be dismissive of low count posters. I spent hours reading Prius Chat before purchasing my car last summer, but never had any reason to post. The positive things I read on Prius chat influenced me to buy my Prius.

I bought the car because I needed a safe reliable car to transport my sick children to and from the children's hospital two hours away. I have a unique situation that puts me at a low threshold for safety issues - yes, I still see it as a safety issue. I can control how I drive, but I can't control what happens when the person who cuts me off slams on their brakes. I don't tailgate, I release the gas way before a stop light, I drive below the speed limit, and I understand the whole 'explanation' behind the brakes (I don't accept it). For some people that might be fine (a quirk so to speak), but for me, it's not. My car is still surging. My children fear the brakes will fail, and I am stuck with a car that sits in the garage most of the time.

 

Well... when it happened to me (and it almost seems like my experience was different than most), I was coming up to a heated crosswalk (in winter) and just before it was a sharp ridge of ice (say about 2-3" high, 5-6" wide). I would say I was traveling about 12-15 mph with the brakes slightly applied. When I hit the ridge, the car beep, warning lights came on (not sure which) and the pedal sank to the stop. The braking force didn't let up, but there was no pedal travel to increase braking either. Fortunately there was nobody in the crosswalk as I came to a stop slightly within the white lines.
Now I did not release the pedal and reapply which others have said helps. But that was not my instincts at the time. I always try to evaluate my approach to stops now, checking the road conditions, etc and leave plenty of room.

 

Deleted, posted under wrong user name.

 

Therein lies your answer. Loss of traction for any reason throws any normal braking operation out of the window.

 

So how do you reconcile the fact that you're the only one who's experienced something like this in both the Gen II and Gen III, when many, many people have never experienced it in either model (much less both)? Could it be that you're hypersensitive to the normal behavior of the hybrid's various features?

You said you were going under 10 mph? Regenerative braking is only effective down to 7 mph so you felt a transition to friction braking?

 

Nevertheless, maybe you've never noticed it before, but regenerative braking is only effective down to 7 mph and you might have felt the transition to friction braking.

 

Owch!

Toyota has gotten beat up for safety and made a number of structural changes. It should not be the same old Toyota from before and we need someone to find out if they truly have a clue.

If you can add the location, I would suggest taking your post, adding the location and reporting it to Toyota via their corporate web interface. Yes, it is fair to share it with your dealer, so they are not surprised. But I think there is merit in having it looked at.

What you have described is a classic symptom of an intermittent connector problem. I can not speculate on what connector it might be, I haven't learned all the systems that well nor done my own experiments. But this sounds so much like a wiring connector issue.

If I know my intermittent problems, they will return. I could loan you an accelerometer to document the event duration. Just send me a PM and we'll work out the logistics.

Bob Wilson

 

Everything has to be a wiring connector issue, huh? Why not the most obvious clue that you're apparently ignoring, regenerative to friction transition at the 7 mph cutoff?

The OP is unable to reproduce the problem at will.