NHTSA Tracking Braking Loss on Prius Hybrids

Why is it easier for some of you to attack the driver than to attack the problem with the car??? It's a real issue. Toyota will have to eventually do something about it- whether it's just EDUCATION of the users on the phenomena so that when it happens it doesn't scare the crap out of them, or adjustment to the systems to reduce the effect- I don't know...but it's REAL. So quit belittling the drivers who've commented about the effect and trying to use this kind of ad hominum attacks. It's very unbecoming of forum members and says more about the mentality and attitudes of those who attack others than look honestly at the issue with the car.

 

That's my point. Until there are enough documented complaints, or complaints that can be reproduced and substandiated by the car manufacturer, then it's virtually impossible to say whether it's a design problem (and we all should be concerned), or driver error, or a unique problem that happened to X number of cars.

 

How about the Star Safety System. On all of your Prius there exists 5 safety systems that are all based on the ABS.

First about the ABS, I'm sure that we all know that it pulses the brakes so you can maitain steering under hard braking. This system uses a 4-channel ABS system meaning that it takes the speed of all 4 wheels into consideration when it applies brakes. If one wheel is on a slippery surface, that wheel gets less brake force than the other 3. What then when the next wheel hits that slippery surface? Might you feel a transition in the feel of the brakes? That transition is the ABS system doing its job.
EBD- Electronic Brake Force Disribution adjusts brake forced front and back & side to side based on the load in the car. If there's a heavy person on one side of the car and no other passengers, the front driver's side wheel will get a 'bit more brake force applied to it. Cargo in the back? More brake force there. Certainly there's going to be a different feel in the brakes as the brake dynamics change as the load & location of the load changes.
Brake Assist- ensures that maximum brake power is at the wheels when your foot hits the brake pedal quickly. That quick strike tells that car that you're entering an emergency braking situation. Add ABS & EBD to that panic stop, might there be a different feel in the brakes when compared to your average brake application? You bet!
TRAC- Applies brake force to a spinning wheel and reduces throttle out-put when there's low or no traction. Traction control doesn't apply here but it's part of the Star Safety System and it's important that everyone knows what it does
Adanced VSC- the advanced vehicle stability control is at work more often than driver's are aware. Advanced VSC uses steering wheel input ( are you trurning the steering wheel? ), a yaw & roll sensor ( is the car in a tip and/or turn ), and ABS wheel speed sensors to determine if the car is about to lose control.
VSC will reduce throttle out-put, apply brakes to one or any of the 4-wheels to regain control or correct a skid. These all happen regaurdles of driver's input ( steering, gas or brakes!)

Let's talk about what these systems are doing in the situations that you encounter with a loss of brakes.

You enter a corner at speed. You hit the brakes.....
Brake assist squirts extra brake fluid into the system because your foot hit the pedal quick and it says..."Your panicking, let me help."
ABS kicks in to give you steering control and prevent the wheels from skidding. the VSC activates because the car is in a turn and the sytem is worried that you're going to lose control of the car. Maybe it made a correction to the speed of the wheel on the outside or inside of the turn?!
Did the brakes feel differently in this situtation than in your day-today braking at the stop light? Yepper!

These systems and their operation are the same in uneven pavement, gravel on the road, etc.
I don't believe that there's a defect in the systems of the car or that the brakes don't work correctly. I believe that the Salesman that sold you your car didn't explain how each system works, what they do, and how they might react in a given situtation.

I've owned/ own an '06 Tundra, '06 Corolla, & '06 4Runner. Each had ABS brakes & Star Saferty. My current rig-the 4Runner has all of the systems listed here. I've experienced what seems to be a cut in brake power, but really....it was because star saefety system was working on keeping the truck going straight and applying the brake force to the correct wheel(s).
I've driven Prius from years '05-'10. I drive 'em in snow and ice over gravel roads. Over hills and around corners and have stabbed the brakes to show my customers what the car does. These systems make adjustments that can surprise you, but I tell you, the first time you go ripping around a corner/ hill combo, find a car stopped in the middle of the road...you'll stab the brakes, and sharply turn the wheel to avoid that car....the Star Safety system will do its job and you'll come out of that situation safely. Heck, you'll probably be impressed. I was.

 

If you go over to the thread where Bob Wilson is endeavoring to document and track where these incidents occur, you will see there is no "belittlement" of drivers reporting their experience. HOWEVER, posters who come on this site, and who's purpose (as so it would appear) is nothing more than to insight and flame the fire with rhetoric...then yea, they should come under criticism. There's an aweful lot of hysteria right now about anything and everything having to do with toyota products. There have been posters on here claiming deceit, lies and cover-up by Toyota. We ask - Where is the proof of these slanderous allegations? I have no doubt, no doubt what so ever that some of these "1 and done" posters don't have a Prius, and are nothing more than trolls fanning the fire. Anybody that's been on sports web sites, like ESPN, knows exactly what I'm talking about, and how easy it is for a troll to flame the fires on any issue.

An unfortunate reality of the intenet is that many people believe everything they read on the internet. Unlike most city newspapers, what's posted on the internet does not have to be verified. People can put up anything they want. Newspapers can not operate that way, because they could be found liable for what they print. Many Americans don't have either the interest, nor the capacity to farret out truth from hype (or out and out lies). What's real, from what's not. To be honest, I think if more sites self-policed, and challeneged posters to back up their allegations with information, links, etc, web sites like this might actually be more useful for people seeking the truth.

But I would like to revisit two earlier points that I've made, that still have not been answered:

(1) G2 owners have reported a similar sensation on their vehicles. So this sensation (or problem) has been around quite a long time. So where has NHTSA been on this? Why haven't there been any (at least) investigations - if this is real? Why? What I find ironic is - everybody has been pointing the blame on Toytota (they should have done this, and that years ago, etc, etc)....but what about the NHTSA? Isn't it their JOB to safeguard the motoring public. They certainly have the LEGAL AUTHORITY to suspend sales. So what's there part in all this? If it's real, and they have the data they need, why haven't they acted before now? Surely after nearly a millions Prii sold in the US, over the past 11 years, there is enough data on this phenomena by now?

(2) Is this sensation (issue/problem) unique to America? Why have we not heard similar complaints from Prius drivers in Asia and Europe? Maybe they don't have bumps in Europe and Asia? LOL. Or is it a plot by Toyota to only kill Americans? LMAO. I know there are a lot of posters on this site from England. Maybe they could weigh in on what they hear from across the pond?

 

I've driven Prius from years '05-'10. I drive 'em in snow and ice over gravel roads. Over hills and around corners and have stabbed the brakes to show my customers what the car does. These systems make adjustments that can surprise you, but I tell you, the first time you go ripping around a corner/ hill combo, find a car stopped in the middle of the road...you'll stab the brakes, and sharply turn the wheel to avoid that car....the Star Safety system will do its job and you'll come out of that situation safely. Heck, you'll probably be impressed. I was.

So what you are writing ,that Toyota in the base price of the car should include a skid school course and about 99% of the problems would go away that would :rockon:

 

The last car I bought, prior to the Prius, they (the manufacturer) included a 3 day advanced driving school as part of the sales price. I would have bought the car witghout this, but this was a nice bonus, and I would recommend that everyone take some advanced driving class at some point in their driving lifetime. I learned an aweful lot about how to handle a car - in emergency situations - and about the capabilities of the car I just bought. yea, it would be nice if Toyota did this...?

 

Funny that you should suggest that. Occasionaly us sales guys get to "Ride & Drive," the new models when we go to the regional New model launches. A lot of the experiences with these systems comes in these ride & drive classes.
The '07 Tundra Launch was the eye opener to me in terms of the Star Safety System and its behavior when compared to Chev, Ford, Dodge & Nissan. We drove all 5 vehicles back to back to back in different situations ( closed course with a 3,000 lb trailerand 500lb in the bed ).

Toyota's ABS and ABS based Star Safety System is so far advanced when compared to other manufacturers.
I had a professional driver in the truck with me explaning what & why for everything the truck was doing when I swerved, accelerated, braked hard & swereved, drove the truck over staggered ramps. These same systems exist on the Prius and in some cases started on Prius ( Advanced VSC )

 

When my 2003 Prius hits a bump the regen disables and the friction brakes take over. There is no pause in the braking, just a slight change in braking feel. If I want regen again, I let off and reapply the brakes. Bob told me about this phenomenon when I first got the car. No big deal. You can see on the graham scanner as the regen Amps drop off. This would be needed for the ABS to start working.

Once you know what it is, it's no big deal and you get used to it. All cars have their quirks. The Prius is still the one of the best and safest cars on the road today.

All this hysteria is sad. Perhaps Toyota got a bit too big for some peoples taste. I'm not swayed by the media reports. They are full of misinformation and half truths at the best of times.

 

I only got to page four, I'm quite lazy. This is going to be a very scary thing when this happens. I havent even bought the car yet, but I'm used to MAJOR stopping power. I have two cars with massive 14+ inch brakes. So I hope they can fix this or make the crossover delay much shorter.

 

Scary?

It was not to me. Just push down a bit harder over bumps, and I doubt you will even expereince this...since adjusting my braking/peddle pressure, I have not had a re-occurance of this phenomena.



Use to "MAJOR stopping power".

The prius has excellent stopping power. Better than most, with multiple systems. What car do you drive so we can compare?

 

There is no pause. There is nothing to fix. It's an instant transition and not scary at all. The stopping power remains the same, oh first time poster.

Most people don't even notice it. I drive a first generation and the transition is a bit more noticeable to me but the newer cars are even better. I notice it because I'm interested in my car and learned about how it all works.

The Prius is one of the safest cars on the road with one of the highest customer satisfaction ratings. Reporters suddenly have a ratings grabber so they are dredging up anything they can find.

They should report on the defective brakes on the GM product. Or the ten thousand deaths every year from SUV rollovers. My neighbour bought a Pontiac Montana and had one of the front disc brakes seize up on him after owning it for a month. They fixed it and it happened again.

 

First off, we found only half of the folks who answered a 30 day poll reported even experiencing it. Given PriusChat is likely to attract folks with a concern or question, speculation, but the true rate is probably a lot less.

Of the responders, less than 20% reported it was a 'severe problem.' But think about it, 80% have either never experienced it or don't consider it a big deal.

About half of the incidents occurred at speeds under 20 mph. This suggests it is a low-speed event. Independently, we found there is a control law built into the braking system at 19 mph and reports cite it is also associated with 'light braking.'

Now I'm not one to pander and folks who want to complain or "cut and paste" posting soon join my "ignore" list. I have no time for whiners. But I am curious and since I can't replicate the problem to any degree, I'm only paying attention to those who bring something of value to the discussion ... Facts and Data:

1. Many report is it intermittent, it doesn't happen every time.
2. Repaving the street clears the problem. (This suggests non-Prius drivers have problems too but they don't come here to complain ... Get a clue! This is a road maintenance problem!)
3. How frequently in 2010 Prius owners? Less than half and less than 20% considered it a 'severe' problem.
4. Where has it happened? This means Google, Google Street View, or photos of the locations. So far, it seems to be a Northern latitude problem and parts of the west coast. We have 15 photos of less than a dozen sites.
5. Speeds? Half under 20 mph.
6. Press harder? The car STOPS NOW! The driver can always come to a stop by firm application of the brake.
7. Accidents and injuries? None reported.

We continue to ask folks who have experienced this problem:

• share location - either photos or Google or Google Street View of the location. If someone isn't committed enough to supply this basic information, they join the 'noise'.
• share symptoms - speed, frequency
• swap Prius - see if a loaner or rental or another Prius and driver experiences the same. My understanding is test drives by Toyota Service personnel have yet to experience the same event. In fact, one person reported it happened in the dealer lot (and never came back with more details!)

I live by facts and data and as long as there are folks who will step back and deal with reality, we'll get along. But whiners and complainers and FUD merchants need to 'get a life.' Like Eldridge Cleaver once said,

If you're not part of the solution, you're part of the problem.
​

Bob Wilson

 

Fan boys that don't own gen III please shut up and go away

That goes for those complainers that haven't driven one either.

orange4boy, I have driven it, and it is different then your imagination. Does that make my opinion better than yours. Yes.

There is something going on. Bill wilson and most of the gen III owners seem to have valid opinions. Gen II owners think they know something, and are defending the brand. This just makes you look like idiots. I'm not including those like dogfriend or others that are trying to understand it.

This is a Gen III problem, so don't pretend that since it doesn't happen on your gen II it is not happening, and those that experience it are just complainers.

I put in the poll that it was scary and needed to be fixed because I was able to recreate it after a lot of trying. There have not been accidents yet, but that does not mean that there won't be. This may just be dangerous on a very small percentage of cars on a small percentage of roads, which is more of a reason to look at it with an open mind.

btw: I hate the brake assist. Its gone on my car twice in 2k miles. The last time I almost was rear ended. Its something that I will learn to control, so its just a funky thing with toyotas. The brakes releasing from regen is potentially much more dangerous.

 

Excellent! Excellent, and more excellent! Seriously, great synopsis. :music: to my ears!

:thumb:

"If you're not part of the solution, you're part of the problem." The motto of the 60's. It's still valid TODAY.

Right on, dude! :rockon:

 

Re: Fan boys that don't own gen III please shut up and go away

Exactly! This is not a 'set your hair on fire' problem but it shouldn't be ignored. We need more facts and data and that means patience and dealing with reality.

BTW, thanks for the railroad crossing identification:
http://hiwaay.net/~bzwilson/prius/Prius_bump_040.jpg

Any additional details?

I just wish we get some of the other Austin Prius owners to replicate your experience. Alternatively, get a loaner from the dealer and see if is does the same thing. We need to find out if it is vehicle specific. If so, it might be corrected by having the service center perform a full diagnostic test and recalibration. Recalibration is a well documented but somewhat involved process ... the yaw sensor has be to exercised precisely.

Bob Wilson

 

Since this thread is titled "Re: NHTSA Tracking Braking Loss on Prius Hybrids" and not "Re: NHTSA Tracking Braking Loss on 2010 Prius Hybrids" and since there is no prohibition for me to do so, I will continue to post here, thanks very much.

Wow, mellow dude.

In case you didn't read my post I never said I had driven your car. Apparently the poster to whom I was responding hadn't driven yours either. I was relating my experience with my prius to a poster who had never driven one and didn't have a clue about how they operate.

The Prius has not changed that much through the years and the Gen 1 has mostly the same systems at play here as described in the article linked to by the OP.

 

I will be the first to admit, I know nothing of these cars or how they work.
I actually have driven one. I test drove it just yesterday, and I plan on going back monday to get a quote on my trade. I was just concerned seeing this because I'm about to trade in a perfectly good 370Z on something a little more family oriented than my STI or pickup. So my concerns are perfectly validated. I'm interested in the safety of my family. Hybrids are new to me. These systems are new to me. I worked on a few at school, but not in depth as you have an understanding of.

 

Thats why I'm looking into to buying one. I've never owned a toyota, but I would like to. This little braking issue was not noticed by me, even when driving on broken roads and uneven pavement. I'm pretty sure I can handle whatever this car can throw at me. I'm just wondering if there is a real PROBLEM or just enough people that have "issues" have come out more than people praise the car.

Every NEW car has its little issues. This one will be solved if it turns out to actually be one.

 

Here's my take...if you can handle a Z, then you can handle a Prius. Seriously, it does feel different than most cars (I own two Jags), but if you know how to handle a car (some here apparently don't), you'll be just fine. It's a high-tech car with a number of systems that may make it feel quite different from what you are use to. As long as you appreciate this going in, I'm sure you will be fine.

By the way, the one surprise I got after buying the Prius was how responsive the gitty-up was with this car in the "PWR" mode. Surprisingly quick.