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I immediately drove the car straight to the Toyota dealarship in North Arlington, TX and left it there. They ended up driving it for minutes and could not get the brakes to fail. I had informed them that they would need to drive it for a month (since it happened once per month). They ended up sending me packing, with a $1,000 rental car bill as well as a damaged Prius that they claimed no responsibility for.
TRUST ME THEY HAVE A BRAKE FAILURE PROBLEM.
Somebody needs to check how many people have perished from driving into intersections because their brakes have failed.
I almost lost my wife and kids on multiple occasions, because of their faulty brakes.
YOU HAVE BEEN WARNED!!!
And yes, I immediately traded the car in on a new car that was not a Toyota.
One time to my wife last year when the road was covered with 3 inches of wet snow.
Going home from work she told me every time when she tried to brake and make the right turn, the car wouldn't slow down and she missed the turn. She missed a couple
turns. Luckily there wasn't any body on a snowy road.
And I thought her driving skill in the winter wasn't that good. She does not drive in
snow storm often.
Happened to me twice this winter and I thought the tires don't have enough tread depth.
On each occasion, the road was covered with 1/2 inch wet snow and on a slight slope.
The car just wouldn't stop when I applied the brakes.
I posted this problem on Lexus GS350 board more than ago,
Sometimes accidents happens due to circumstances beyond our control, poor driver skills or judgment. Those of you that are truly unhappy about your Toyota, trade it in for a GM or Ford. Both these companies are offering $1000 extra rebate for a Toyota trade.
I have 45,000 miles on a 2005 Prius, with no braking problems until this last month when twice my lady has reported to me that the brakes grabbed hard when she pressed the brake pedal lightly. Someone else reported a similar thing in this forum.
Toyota says Prius had brake design problems
Toyota says Prius had brake design problems, already fixed on some models but not on others
that was in the news today
I am supposed to get delivery on my newly purchased Prius this Friday.
How do I know which cars were fixed?
I dont want to relay only on the salesman knowledge.
I called my dealership today - they offered me a rental car while they wait for a fix from Toyota. I am nervous about that - they have no concrete word from Toyota as to when the fix will be released.
Please! For your own safety, if you have a Prius (especially 2010), do the following test:
1. Find a street or parking lot with a small pothole or uneven pavement (doesnt have to be huge - just enough to cause a good bump as you drive over it) where you can safely test the brakes.
2. Drive over the pothole at about 20mph - making sure brakes are applied before you drive over the bump
3.) As soon as you hit the bump, you will feel your car 'lurch' as the brakes shut off.
4.) If your car exhibits this behavior - file a report as soon as possible with NHTSA.
On the morning of June 9, 2009 I was traveling South on I-93 near the town of Medford, MA. I was on my way to Logan Airport to return the 2009 Toyota Prius I had rented that previous Wednesday. It was approximately 9:30 AM; the freeway was still bumper-to-bumper with rush hour traffic. I was in the left-hand lane of the highway and traffic was stop and go.
A gap opened up in traffic and I accelerated. The car in front of me (approximately 60’ ahead) suddenly stopped. I slammed on the brakes but my car kept going. There was nothing I could do as my car plowed into the car in front of me, at the speed of approximately 10 mph. The impact was sufficient to dislodge my license plate. There was no apparent damage to the car in front of me, however the two passengers were extremely shaken up.
There was a Massachusetts state trooper on the scene who took all the information but did not file a report. As soon as I could, at about 11:00 AM, I called my insurance company, USAA to report the accident, and I explained all of the details to them.
It is unfortunate that these problems are just now getting attention. Think about how many accidents could have been avoided if this issue had been brought to light sooner.
With these hybrids when you apply the brakes the system is biased toward the use of regen braking, more HEAVILY biased the lower the hybrid battery charge level happens to be.
So, you're braking moderately, using regen braking only, in order to come to a reasonably gentle stop. Then for whatever reason (pothole, railway rail, plastic crosswalk stripping, wet/oil spot, etc) ABS detects impending wheel lockup and instantly DISABLES regen braking in favor of frictional braking only.
Note: In many cases you may never know ABS has "activated".
Now, for a brief moment you might feel a "surge" forward due to the transition period between the time of disabling the regen braking and the frictional brake pads coming into contact with the brake rotors hard enough to reach the same level of braking you had just previously.
Even worse if the street is oil and rain slicked ABS will kick and you you might well feel that as brakes grabbing. It is not at all unusual for ABS activation to result in elongating your braking distance in a fairly slippery surface by an extraordinary measure.
Since I do not drive a Prius, I will from now on turn on my hazards when it is raining and there is a Prius behind me.
Another problem I noticed is that when the road is wet, and if I was at a complete stop and tried to accelerate too fast, the car will actually kind of "slip"--it doesn't accelerate as intended but actually stalls momentarily. The way to overcome this problem is to step on the gas pedal very lightly. So with slow acceleration, everything is fine, but if you tried to rush it, it won't work. This is a severe disadvantage if you are sitting at a busy intersection trying to make a turn, because you want to go fast to avoid be hit, but like I said, trying to go faster will actually backfire.
Has anyone else noticed this?
However it is a whole new ballgame when computers start playing up.
I just think of this thing in front of me and the problems I have, with a need to power cycle the thing every month or so. You cannot do that travelling at 70mph.
Better the old days when brakes were a mechanical function you always seemed to have warning when things were not right.
That's called TC, Traction Control. If you try to use too much engine torque for roadbed conditions the drive, driven, wheels will tend to slip. When that happens TC will activate and instantly reduce the drive power from the HSD system. Most of the time it will also apply braking to the slipping wheels.
With a FWD or F/awd vehicle wheelslip/spin of the drive/driven wheels is of such seriously hazardous nature, HIGH potential for subsequent loss of directional control, that the TC reaction to the must be INSTANT, full and complete.
If you happen to also be turning as you accelerate the TC (more likely VSC)functionality will likely be even more firm and sudden.
Keep in mind that for its weight the Prius has an unusual level of get up and go from a full stop. Low speed torque derived from those synchronous AC motors.
No, not saying that at all.
What I am saying is that if you drive any of the current crop of hybrids that use regen braking you should be prepared for that seat of the pants "feel" of a momentary, millisecond, forward surge. In most cases that momentary "lurch" in brake application will have no detrimental effect.
We have a 2010 Tacoma 2.7L Auto and after 16,000km (10,000miles) I am bothered by its braking performance and wonder if there are some common software/hardware related deficiencies in Toyota's products, I have two questions.
1. This is our first ABS vehicle and it does seem to be harder to stop with ABS than our old Civic with non-ABS brakes on snowy or icey surfaces. Are there any quantitative results for ABS vs non-ABS performance?
2. The Tacoma also exhibits unexpected brake-force requirements. Usually requiring more force than I think is warranted but occasionally responding to my idea of normal braking pressure. Is this appearing on the Prius as well as other models in Toyota's line-up?
On a highly slippery surface it will sometimes help to apply the e-brake slightly/judiciously along with normal braking. I have had times when it seemed my Jeep would never come to a final, full, stop due to continuous ABS activity. The e-brake would always help.
2.) "..unexpected brake-force.."
That may be due to BA, Brake Assist, if you happen to have that feature. With BA the braking system "watches" the rate at which you depress the brake pedal in order to determine if "this" is a panic or severe braking event. If it determines so then it will actually use the ABS pumpmotor brake fluid pressure to assist your braking effort. In that case it might even extend the HARD braking period should you relax brake pedal pressure somewhat.
As a result "normal" braking will often require more brake pedal force vs if the system detects panic braking and provides the extra assist.
When I drive over bumpy surfaces, a large pothole, or an area with a dip in the road, the car stutters and lurches and the VSA light flashes. Sometimes the car's reaction lasts for several seconds after hitting the pothole. It seems to exacerbate the problem if I am turning or braking. I should point out that I experience this lurching and stalling sometimes when I am simply driving along at 35 MPH and hit a pothole. So it doesn't really seem to have anything to do with the brakes.
Like many here, I kind of ignored the problem and assumed it to be a normal part of the vehicle stability function. There have been some situations where it came close to making the situation much worse.
I also notice the problem accelerating, when the car slips and stutters and the VSA light flashes. This is usually when I am trying to pull out quickly from a driveway or make a quick turn. This is very frustrating (and sometimes scary) on busy roads with oncoming traffic.
For the other problem, yes it is very frustrating and dangerous in my opinion. I have had several close calls with other cars almost hitting me, when I thought I'd be able to accelerate in time but instead got stuck in traffic. If this issue is pervasive for all hybrid cars, then I am not going to buy a hybrid again.
I do encourage everyone else to go ahead and file a complaint via NHTSA. So far it seems like Toyota is only considering recalling the 2010 model.
re: ABS characteristics: Intuitively, it always seemed to me that, if one could just hold brakes close to the loss of tractrion point, then stopping would be faster than ABS pulsing which has a percentage of no-brake force at all. Thanks for the confirmation.
re: Unexpected brake-force. Yes, our 2010 Tacoma does have BA (brake assist). I will explore the conditions you suggest will cause the variability.
The whole purpose of ABS is to shorten your stopping distance, not lengthen it. It is a very effective system on most cars. Toyota apparently does not have the interaction of the friction brakes and regen braking worked out yet. So in the meantime, I will be turning on my hazards when I see a Prius behind me since my car has ABS that does what it is supposed to do (shorten stopping distance) and will thereby avoid getting rear ended by the half baked Toyota if there is a need for some hard braking.
I probably should also turn on my hazards when any Toyota is behind me to avoid getting rear ended because of some unexpected acceleration event. The roads just aren't safe anymore.....
Is to optimize braking ability along with directional control simultaneously. Read any current owner manual to verify this. Absent ABS during hard/heavy/panic braking there is a clear and certain danger of loss of directional control due to the front tires locking and skidding. ABS activation results in allowing the brakes to exert the maximum level of braking while still allowing the driver to maintain directional control.
Once someone develops an inexpensive (cost-effective) "linear" brake application servo system to replace the current "bang-bang" system things might improve significantly.
Until then it would clearly be wiser to disable ABS until VSC detects the need.
"..It seem to exacerbate the problem if I'm turning..."
If the Traction Control system detects front wheelspin/slip and you are turning then it is QUITE CLEAR that you are applying more engine (HSD) torque to the front wheels than is safe for current roadbed circumstances. This is a FWD vehicle so loss of traction, even momentarily so, on the driven and stearing wheels must be quickly addressed, moreso if the VSC system gets into the act. So in a turn wheelspin/slip will probably result in the activation of both functions, TC and VSC.
Your Prius has an unusual amount of low speed acceleration torque for its weight along with tires that are primarily designed for low rolling resistance, not TRACTION.
BMW apparently applies just enough brake fluid pressure to the calipers to bring the brake pads into slight contact with the rotors. That apparently helps to keep the rotors dry in case the brakes needed.
Talk about "torque" stearing...!!!
In the situation you describe, disparate braking traction right vs left, there is a design aspect of ABS (and VSC) that prevents the wheel on the higher traction side from applying an inordinant level of braking vs the opposite wheel. To do so might result in the car skidding out of control in the direction of the high traction braking.
In the very same situation, WITHOUT ABS, I can apply "full' braking, and stear (something ABS [VSC] cannot yet do) counter to the skid to maintain a straight line.
By DEE-ANN DURBIN AP Auto Writer
DETROIT February 6, 2010 (AP)
Toyota has told dealers it's preparing a plan to repair the brakes on thousands of hybrid Prius cars in the U.S.
In a message sent Friday night to dealers, a Toyota group vice president, Bob Carter, said the company is working on a plan and will disclose more details early next week. More than 100 drivers of 2010 Prius cars have complained that their brakes seemed to fail momentarily when they were driving on bumpy roads. The U.S. government says the problem is suspected in four crashes and two minor injuries.
Public awareness of the problem "has prompted considerable customer concern, speculation, and media attention due to the significance of the Prius image," Carter said in the e-mail. "We want to assure our dealers that we are moving rapidly to provide a solution for your existing customers."
You're miss-quoting somewhat, if your intention is to "destabilize" you apply the rear parking brake AND crank the stearing hard one way or another. Otherwise applying the parking brake might well result only in your coming to a slow and STRAIGHT stop.
Back in my wintertime days in MT I often found myself using the parking brake slightly, judiciously, to maintain a straight line going down a slippery roadbed slope. Nowadays ABS would undoubtedly make that a bit easier.
If we could INDIVIDUALLY hold brakes...
Yes, that would be "true" threshold braking, using the UTMOST benefit of whatever level of roadbed traction exists SOLELY for bringing the vehicle to a stop or to a lower speed. Should an inexpensive or cost-justified anti-skid control system (CVB, Continuously Variable Braking) ever be developed it could be used to provide true threshold braking AND stearing. Available traction allocated FULLY and SOLELY to stopping or slowing UNLESS VSC indicates otherwise.
In the meantime...
ABS is primarily intended to maintain directiional control in an emergency braking situation and it does this BY PERIODICALLY REMOVING ALL BRAKING FORCE to allow tires to periodically regain their grip on the road surface. Since you don't have braking force all the time you can't stop as well as you could if you could properly control the brake force yourself.
ABS induced extended stopping distances are particularly noticeable on snow, ice and gravel --- just when you need optimum stopping ability. The problem is so pronounced that off-road vehicles often have an "ABS OFF Switch" to make off-roading in mud, sand, snow, icy and hills much safer.
The 2010 Toyota Tacoma manual covers this on page 195 under "CAUTION' which states "Stopping distance when the ABS is operating will exceed that of normal conditions" and "The ABS is not designed to shorten the vehicle's stopping distance."
There should be similiar warnings in your owner's manual.
Hope this helps.
If ABS detects impending lockup of any wheel due to braking forces it will FULLY release brake fluid pressure from that wheel's brake caliper just long enough, 10's of milliseconds, to alleviate the issue of the wheel actually coming to a full stop. That almost never requires removal of all braking force, "full" retraction of the brake piston.
Think of it as PWM, Pulse Width Modulation, of brake fluid pressure, in order to "mechanically" maintain an "average" braking force.
Most "off-road" vehicles will automatically disable ABS and VSC when the center diff'l is locked.