Unintended Acceleration -- While Parking

Race conditions are not inherently hard to track down, only race conditions with infrequent outcomes. It is the nature of all infrequent intermittent problems that they are hard to isolate. A race condition that splits 50-50 gets the designer's attention pretty quickly.

Getting back to the Prius, it is entirely possible that a logic fault exists that can cause acceleration, just as it is possible that cosmic rays could be flipping bits in the ECU. But we also know that this fault, if it exists, is very, very unlikely. Otherwise we would have a large number of unexplainable incidents.

So far all analyzed incidents have been shown to result from driver error or mechanical interference. Perhaps we have a simultaneous failure of the ICE ECU and the data logger in the brake ECU. This would account for the SUA and the lack of any logged braking activity. However, this dual failure explanation takes an already unlikely scenario and moves it into the realm of vanishingly small probabilities. It's not impossible, just ridiculously unlikely.

Tom

 

The Therac incident was not a race condition - it was caused by incorrect handling of backspace (what the display showed and the actual machine setting wee different).

One reason I have a problem with taking these anecdotes of UA seriously because it requires a fault not just in "the logic chip" but in 3 or four separate systems simultaneously - it is not all handled in one computer:

1) The throttle has to be misinterpreted incorrectly
2) The failsafe on the throttle has to fail (there are two signals that have to agree)
3) The brake override has to fail
4) The mechanical brakes have to fail - the brakes are more powerful than the engine in the Prius - especially at low speed.

One possible cause is that the driver is swiveling in his seat and in so doing accidentally moves his feet and applies the throttle instead of the brake. The driver thinks he is applying the brake so of course that's what he will report - there may not be any conscious "lying" - it was driver error.

kevin

 

I guess my only response is that no one seems to care - this has been going on since day one, and Toyota has totally ignored the problem. making excuses and blaming the driver. It is a real problem that will not go away by wishing it to, and when enough people get hurt or killed because of the defective ABS system, there will be a major law suit. This seems to be the only way that Toyota will take any meaningful action.

 

Was it truly necessary to quote his entire long-winded post? lol

 

While I agree with you, I guarantee you there were some conscious lying going on, especially if the car was undamaged and during the height of the media frenzy, if the Pepsi scare is any indication. If people were stupid and sick enough to lie about needles found in Pepsi cans, you can be sure they'd do the same to the Prius.

And what's the outcome? Still nothing.

 

It was only a matter of time when a disgruntled Prius owner (who is still pissed about the braking problem and promised never to buy another Toyota again) comes in to side with evpv and of course evpv thanked him/her.

 

All of the above was started as a result of the media frenzy back at the first of the year. The litigation is ongoing. It appears that you are just now catching up to it.

You would think that if there was a true UA issue with Toyota that some positive proof would have been discovered and announced by now with all of the different institutions studying the issue. That is not to say that something may eventually be found but the longer it takes the less the probability.

 

Tell me you're kidding - right? With as much coverage as this issue has had, how can you possibly believe this!

 

I thought the beginning portion of the piston movement in the master cylinder was monitored and used to electronically control regenerative braking, but if you stomp on the brakes hard enough for the piston to reach the back end of the master cylinder, I thought there was a more traditional hydraulic connection to the brakes? Is that not true? If it is true, and if the brakes are strong enough to hold the vehicle still while the accelerator attempts to move the vehicle, then I don't understand how unintended acceleration is possible while pressing on the brake.

 

Because his friend "Modulated" the gas instead of the brake in order to stop!
I did not turn out vey well however!

 

27 pages over 9 months? sorry, what was the pertinent info? how bout this guy nylion? did he disappear? i liked his statement "i wasn't sure if i could trust my senses". senses? if i took my foot off the brake at a stop and the car went into full accelleration, and it did it more than once, i wouldn't question my senses, i would be at the dealer showing it to them! did he ever duplicate it for anyone? seems like it was happening all the time.

 

No, this is not true. During normal operation the brakes are entirely "by wire". It is correct that the master cylinder pressure is monitored by sensors and used as a control input to the brake ECU, but the hydraulic pressure couples only to a stroke simulator, which makes it feel like normal brake pressure.

In the event of a failure, valves in the brake system fail over to a safe position, removing the stroke simulator and connecting the master cylinder directly to the brakes. Only then are the brakes mechanically operated by the driver's foot (other than the parking brake).

Tom

 

Yep, just like the youtube video below. Notice how the BMW was at the perfect distance and time when the individual (claimed to be a 60 year old lady) should have hit the brake instead of the gas. Same thing with the woman who took a 16k loss to get rid of her "defective" Prius. Same thing with the reports of obligatory 80-year-old man who plows down farmers market in whatever car that we seem to get once a year.

I posted Nylion's farewell thread earlier. He traded in his replacement Prius (a V with ATP) for a 2010 370Z because he missed the fun of driving. For all we know, Nylion could have been crazy individual who appear totally normal and coherent on the surface (like many serial killers) and made it all up just like the Pepsi "victims" who planted needles in the cans or it could have been a driver error that he kept repeating or it could've been a real, isolated issue with the car itself. We will never know in the absence of physical evidence.

 

I will not go back and take the time to do that. It's obvious. My point is that you have been completely single-minded in your approach, and I feel you have ignored many of the well-thought out posts - which is your right, I guess. I really wonder why you posted in the first place. I find the other posts way more convincing than your arguments, which is my right, of course. Honestly, I think it is in your best interest to get rid of your Prius (if you have one), and have your friend do the same. You will never be satisfied with what anyone writes here, and never comfortable driving a Prius (or any Toyota). I would suggest a Honda.

 

evpv,
dont get discouraged by the negativity that seems to come from a few membors in this community. Some of us have an open mind and are anxious to learn more and see what NASA and other agencies investigating these issues determines. Heck if everyone took the view of the members on this forum the previous recalls on the prious would not have happened as we all know that the prius is infallable and every problem with the car has always been operator error. right!!

 

I wouldn't rely upon Snopes for unbiased factual information...maybe if what they have written is well documented, but their political slant made glaringly obvious during the 2008 Presidential election keeps me far from using them as an objective source of facts.

 

The Pepsi scare of 1993 is all over the net, not just Snopes. Google it.