Got into an accident today due to brake problem =(

Traction/Stability control can't be turned off, that's hazardous.
The low resistance tires aren't very grippy, that's hazardous

What more do you want to whine about?

 

No -- I was referring to the brake software update campaign.

 

Message delivered:

Road work areas can reveal brake problems including the Prius.
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Thank you. Have a nice life with your new ride,
Bob Wilson

 

Last I heard, the Camry was the car with the most reported cases of Toyota Sudden Unintended Acceleration. I hope you won't have to be give a first-hand account of yet another Toyota gremlin.

 

Bob,

I experienced the "momentary loss of braking" on this offramp last weekend.

[ame=http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Fourche+Dam+Pike,+Little+Rock,+AR&sll=37.0625,-95.677068&sspn=30.599615,85.166016&ie=UTF8&hq=&hnear=Fourche+Dam+Pike,+Little+Rock,+Pulaski,+Arkansas+72206&ll=34.715308,-92.190996&spn=0.000977,0.003621&t=h&z=19]Fourche Dam Pike, Little Rock, AR - Google Maps[/ame]

I was slowing down in a normal manner from about 65mph when I first exited the freeway to 0mph at the stop sign. Somewhere in between (I estimate the speed to be around 40mph) my 2010 Prius went over a rough patch of pavement and it felt as if I had hit a patch of ice or momentarily lost braking. The weather was not a factor, it was a warm and dry day, road was dry with no visible debris, construction, etc.

My Prius has already had the recall campaign performed for the brakes. I have not taken it to a second dealer to verify the update was performed.

I have been driving a Camry loaner car since Tuesday and have driven on that same off-ramp several times since then, in approximately the same manner and in all weather conditions from wet to dry. I have not felt this problem in the Camry. In fact, there are several places on my daily commute where my Prius temporarily loses braking force consistently and I no longer feel this in my loaner Camry. I actually find myself preparing for the loss of braking in those same spots on my daily commute and now I am surprised when they do not occur in my loaner car with conventional brakes.

So, I guess the regenerative brakes in my Prius momentarily losing braking force could be deemed a "characteristic", and it is something some of us are not comfortable with. I believe that is the point I and others on here are trying to make. In my case, I understand that it allows my vehicle to achieve 51mpg, but I am not comfortable with the feeling and don't accept the trade-off. I understand that other people are willing to accept the trade-off and that's fine.

Thanks,

Troy

 

Eco,

I am sure some one has already said this but it bears repeating. The foot brake has a mechanical linkage. You don't mention using that at all. Please review your driver's ed handbook and take a refresher course in driving. If you were in a construction zone with bumpy roads you should not have been going over 30 mph. The mechanical brake would have stopped the car even if you had your foot planted on the accelerator. You could have stopped the car by putting your foot out the door and stopping it with your shoe.

 

I'd say that is a good analogy. But the factory coach really poked the pooch when it came to teaching relays. Before the software update, I had 3 incidents where they dropped the baton and had to stop and pick it up (partial brake failure with brake drop out for a length of time). The runners speed also wasn't mated, and the new runner was much slower than the old (regen hand off to friction represented a big decrease in braking force that forced increased pedal pressure.

I haven't experienced much of a problem since the software fix. I would not rule out different circumstances cause the partial brake failure that the software update does not address. These are the cases that I am most interested now. They seem to be much less frequent than the problems before software update.

There still is some hybrid finickiness, but this is a more consistant and thus safer behaviour. The baton pass off is not smooth. The first runner regen stops before anti-lock friction kicks in. I vehemently disagree with others that say this is necessary because its a hybrid. The regen braking could be held a fraction of a second longer as rear friction was applied for a smooth hand off. I do agree with the group here that this is part of the hybrid quirkiness and is easy to get used to and drive safely.

 

As I have said in the past, some folks just cant handle the power of a v8 Corvette, or other high horsepower muscle car. Those people should not be driving that kind of vehicle. A buddy of mine went through 3 sports cars, crashed them all. Eventually bought a VW Beetle and is no longer crashing.
Same can be said about the Prius.

 

Thanks! This is the type of detail needed. The '40 mph' sounds interesting.

Any better description about the 'rough spot?' What about the rumble strips on the side? Do they trigger the brake pause?

Bob Wilson

 

Bob,

I have not driven on the rumble strips on the side. The rough spots are simply uneven ripples in the pavement and the difference in height of separate road sections, etc. There are no manhole covers or potholes visible.

If you'd like, I can send you all of the places on my daily commute that triggers the same loss of braking. There are several. Again, not happening in my loaner Camry at all. Kind of discouraging, for me.

Troy

 

That would be great. The better the description, the better our chance of trying to replicate.

Thanks,
Bob Wilson

 

Same thing happens to me downshifting in a BMW, it's drivetrain braking, and when you loose the traction.. ugh come on do we really have to explain this?

Yeah, unlike the manual transmission you are already applying brakes and completely out of control of the few milliseconds it takes for the friction brakes to kick in. Who cares, you should know about the problem by now and you should know your car and how it operates. In an eco car that regenerates you should be doing MUCH smoother earlier braking anyway or you really don't need a Prius.

 

Great answer!!!!!!!!!!!!!!!!!!!!!!!

 

I don't know that this helps:

We've had two credible reports:

• Canadian detour, probably washboard, that scared the owner to sell their 2009 Prius. Yet they shared more details with us.
• Obo exit off of I-5, construction area that apparently is in poor shape and the site of multiple, fatal accidents. It is a straight exit that terminates in a "T" but is also subject to considerable road-work effects.
• We've had other reports where the poster disappeared. Now there is no way to understand their road conditions.

The original SSC-A0B fixed an intermittent problem that required a specific set of conditions to reproduce. But it is not uncommon to find a second, intermittent problem, one with a lower rate, was masked by the first. So let's see if these later reports might give us enough information to quantify and possibly replicate.

But let's ask folks making these claims to provide the missing details. Let's see if we can find some way to replicate and quantify it . . . if at possible. If there is something there there, we should eventually be able to replicate it. But let's get all their details.

Right now, I can't replicate these claims. I find braking consistent in the 11,000 miles on our ZVW30 and eventually replicated SSC-A0B and confirmed the fix. But my mind is open and I do have access to gravel covered roads but so far, nothing that resembles their reports.

Bob Wilson

 

I've duplicated the problem many times, but always allow myself enough room. It doesn't bother me. I am however, sorry that I was so rude and snappy. I hate that. Sorry!

 

OH, sorry. I will provide all the details I can. In fact, I might have Austin help me make a video! There is a horrible pothole on an underpass where interstate 70 goes over. Every time I go through there and I am cruising at about 40mph (as described by other posters) I am decelerating in order to get on the on-ramp. The pothole used to trigger it, but now they put a whole bunch of goopy asphalt patch and it's a big messed up rutted bubble. It activates the problem still. It's expected at that one spot. If no traffic is coming I go around. If there is traffic I slow down sooner. I even drive a bit "inefficient" at times but still leave enough room for myself in case I make a mistake driving, or in case someone else makes a mistake driving around me.

For me to have an actual accident as a result of this issue, I would have to experience the issue AND make a mistake either before or after, or have a vehicle make a mistake near me in addition to the problem. It would effectively eat the buffer I normally leave for such a mistake.

I am very loyal to my point of view that it is similar to downshifting. You are braking with the drive-train after all. However, it's actually better in a Prius because when I lost traction on a wheel downshifting it would take me a lot longer to push the brake, and clutch (which I would do during an emergency situation to keep the motor from stalling.) In the Prius this all takes place in milliseconds.

Don't get me wrong, it totally makes my heart skip a beat.. but it keeps me on my toes. I've actually told the dealer the last two times I've been in to specifically NOT apply the fix. I'm hearing people are still having the problem. I'm also not hearing that there is a performance decrease so I might get the fix. Maybe what they fixed is some other problem that I haven't experienced? I mean... is what I'm explaining pretty much it, or is there something else happening that I haven't experienced? It feels like the car lurches forward, but it really doesn't accelerate, it just stops decelerating.