Last post on Sep 03, 2013 at 5:22 PM
You are in the Toyota Prius
What is this discussion about?
Toyota Prius, Brakes, Hatchback, Sedan
Go to NHTSA to file a safety complaint.
Or call Monday-Friday (8 am to 8 pm ET) (888) 327-4236 TTY: (800)424-9153
#203 of 370 Food for Thought
Feb 22, 2010 (6:05 pm)
Interesting message post from http://reviews.cnet.com/coupe-hatchback/2005-toyota-prius/4864-10867_7-31352228-- 2.html?ord=creationDate+desc&tag=rtcol;uo:
""High Rate of Low Speed Brake Failure in 2004-2009 Prius"
by ganderc on April 7, 2009
Pros: Great car except for the brakes.
Cons: Has a rate of low speed brake failures 31 times that of a traditionally-braked car (Corolla). Many result in rear-ending the car ahead with no injury.
Summary: I read that they redesigned the braking systems for the 2010 Prius. That appears to be Toyota's response to the fact that the U.S. Generation 2 Prius (2004-2009) has had low-speed brake failures reported to the National Highway Traffic Safety Administration (NHTSA) at 31 times the rate of such failures reported for the 2004-2009 Corolla, which of course has traditional brakes. Many of the Prius low speed brake failures were in low-speed city traffic, resulting in rear-end collisions without injury. It appears that the several computers that control the complex braking systems were too busy calculating the most efficient way to apply the brakes, and did not get around to actually applying them, until it was too late. Toyota never took responsibility for the problem, but the 2010 redesign indicates they were aware of it. Unfortunately, the NHTSA never initiated an investigation despite the extremely high rate of failures. The detailed failure reports ("complaints") are available to the public on the NHTSA website. The details are these: To April 2009, 2004-2009 Prius has received 44 complaints of low speed brake failure. 2004-2009 Corolla has received 7 complaints of such failures. Given that at least five times more Corollas than Prius were sold during 2004-2009, 44/(7/5) = 31 times the rate of brake failure for the Generation 2 Prius."
#204 of 370 Re: Spoiled Food for Thought [07prius]
Feb 27, 2010 (10:26 pm)
You quoted a message someone had posted in a review thread.
Where is the source data for this obvious nonsense?
The problem is anyone can post a message saying any nonsense they
wish. Don't bet your credibility on "ganderc on April 7, 2009" who appears
to have made something up without citing a credible source.
#205 of 370 Re: Spoiled Food for Thought [bwilson4web]
Feb 28, 2010 (4:37 am)
Here you go....
Answers to Questions About Prius and the Toyota Recalls
Q. What is the problem that led to the Prius investigations?
A. The investigations focus on a new version of the antilock brake systems on the 2010 Prius, which was introduced in Japan and the United States last spring. There have been 124 reports of problems in the United States, and 77 reports in Japan. The problem does not appear to affect earlier versions of the Prius because the brakes were redesigned for the 2010 model.
In a statement, Toyota said, “Some customers have complained of inconsistent brake feel during slow and steady application of brakes on rough or slick road surfaces when the antilock brake system (ABS) is activated in an effort to maintain tire traction. The system, in normal operation, engages and disengages rapidly (many times per second) as the control system senses and reacts to tire slippage.”
Owners are reporting that the brakes fail to work immediately when the car is on a bumpy or slippery surface, or when it drives over potholes. Toyota said Thursday that it had already identified the cause of the problem and corrected it on cars built since January. Toyota officials in Japan said Friday that the company was considering a recall of 103,000 new Priuses in the United States and 176,000 in Japan, but that a decision had not yet been made.
#206 of 370 STILL CONFUSED Re: Spoiled Food for Thought [revit]
Feb 28, 2010 (8:44 am)
BWILSON--I appreciate your effort, but your message confuses me. I was aware of the problem, which you describe, that led to a recall. I had the recall fix at my dealer on February 15 via a software flash upload. Your context seems to be of a recall yet to be announced.
Are you referring to yet another aspect of the brake complaint on 2010 Prii? I bought mine on December 12--and am generally happy with it.
Also, after listening to Mr. Toyoda's and Mr. Inabe's Congressional testimony last week, I presume that we will offered the installation of brake override--without the formalities of a recall.
#207 of 370 Re: STILL CONFUSED Re: Spoiled Food for Thought [masterpanda]
Feb 28, 2010 (10:21 am)
I called my dealer and got an appointment the same day - my computer has now been reflashed. Motivation? After feeling the symptoms just once since I got the car last August, this past Friday I felt it twice. I wish I could feel complete confidence in the upgrade, since I know that most software is not written from scratch but modified from previous versions, and I am convinced that eventually Toyota will need to fix the problem with the previous brake software in the 2005-2009 cars. Will that problem still be in my Prius?
#208 of 370 Re: STILL CONFUSED Re: Spoiled Food for Thought [masterpanda]
Mar 01, 2010 (10:16 am)
Your Prius, any Toyota, or Toyota "like" HSD systems have BTO by default. When you apply the brakes the HSD firmware is designed to enter regen mode. It is not possible to have regen active AND simultaneously DRIVE the wheels. Well, maybe the F/awd RXh or HH with 2 "drive" channels.
While it is possible to specify firmware operation that would give priority to the gas pedal position over regen braking that is NOT very probable. That would not only be a serious flaw in the design but would border on intentional, criminal, action.
#209 of 370 Re: Spoiled Food for Thought [bwilson4web]
Mar 01, 2010 (10:44 am)
bwilson4web: Why does your point have to be made in such a disrespectful way? My goodness, would you speak to me this way if we were talking in person? Right or wrong, I have been very respectful in my posts and expect the same in return. I am not betting my credibility on the review I posted...which is why I called it "food for thought" as opposed to "hard facts." What I experienced is real; I only said "40 feet" in my OP as a gross estimate; in truth I may have been further away, but I cannot be sure, which is why I said from the get-go that I wasn't making a claim that I was not at fault. The '82 MBZ 240D I drove for the past few years had quite a long stopping distance, but I knew what to expect, and never rear-ended anyone in it. I did not realize that the post would be dissected and discredited right out of the gate. I guess I am the kind of person who tries to fully understand someone's point of view before seeking to invalidate it.
Thank you to those who are respectful on this and any forum.
#210 of 370 Re: Spoiled Food for Thought [07prius]
Mar 01, 2010 (2:46 pm)
Look, I'm sorry that it came across so harsh but it has to do with citing credible sources. Our local newspaper has a letters to the editor section and every now and then "people not in touch with reality" post complete nonsense. If I were to cite their letter as a source, any and everyone would be right to condemn me for introducing a bad source. Remember, even fibbers can post.
If you go back to that original source, you'll notice I replied with the actual ratio of Prius and Corollas for those model years and the ratio is ~2.6 to 1, not the '5 to 1' ratio used in his numbers. If he can't get the ratio of cars in that model year right, how are we to trust his other numbers?
Understand he may be right about the counts of "reports" but look at his own numbers:
44 - Prius
7 - Corolla
The problem is 7 is not statistically significant. It is too small to draw any useful conclusions. So his ratio itself is suspect, as well as his counting.
I won't complain if you 'do the math' other than if I follow the same procedure we come up with different numbers. Then we'll discuss methodology and make sure we are seeing the same data. But as it stands, that source suffers from a major self-evident problem and a factually inaccurate count of vehicles.
The reason I knew the vehicle count is I've been looking at the Toyota December sales reports for the past couple of years. This has the total number of Prius and Corollas sold:
#211 of 370 NHW11 vs NHW20 vs ZVW30 brakes
Mar 01, 2010 (4:23 pm)
The ZVW30 Prius, 2010-current, has the redesigned brake system and the recent recall to get rid of a rare, brake pause. The NHW20, 2004-09, has not been recalled but there are reports that it has a similar but less severe pause. The NHW11, 2001-03, is my commuting car and none of my tests have replicated the brake pause.
2010-current Prius - SSC-A0B
You don't have to wait on a letter or call from the dealer. Call your local Toyota Service Center and schedule an appointment. If the service writer gives you any grief, ask to speak to their manager ... keep going until you get the right answer, "Yes, come in and we'll fix it." Alternatively, call another Toyota dealer or ask them if you should call the local newspaper.
The problem is rare and intermittent. Probably the surprise, more than anything else, catches folks off guard. Just press harder on the brake and the car stops almost instantly. In the meanwhile, keep your following distance on the long.
There are reports but sad to say, I'm not having much luck documenting the pause. I have an accelerometer that clearly showed the ZVW30 brake pause but I've yet to find someone with a NHW20 to test. I may have to rent one.
We have a poll going on in PriusChat about the brakes and the numbers are:
55 - Yes, I want it fixed (22%)
41 - Yes, However it doesn't bother me (16%)
153 - No, I don't feel my GEN II Prius has a problem (61%)
So over half don't see a problem. Only 22%, 1 in 4, wants a fix.
I have one and following the same protocol as our ZVW30, I can't find any pause in the braking using the accelerometer.
#212 of 370 Re: NHW11 vs NHW20 vs ZVW30 brakes [bwilson4web]
Mar 02, 2010 (12:42 pm)
Perhaps you could post your general area and someone that lives near you could volunteer.
I have a 08 Prius and I have experienced the the momentary release of the brakes when hitting a pothole or rough road, but immediately after the brakes grab. I have even hit areas of ice and the ABS has always kicked and assisted in a timely stop. So over all I am more than happy with the performance of the braking system. Although I wouldn't complain if they removed or shortened the momentary release when you hit a pothole.