Sudden Acceleration - It Happened To Us Today

Are you implying that this can cause enough of a forward thrust to throw the driver back into the seat as it did his wife?
When I first went over a bad road segment on a downhill off ramp with a stop sign at the end I was lightly braking and felt a very short reduction of braking effort just over and a bit beyond the segment but no acceleration what so ever.

 

That is interesting that the force is sufficient to throw someone back in the seat. I wonder if this depends on the severity of this event? The first time I had this happen on a downhill ramps with light braking, it certainly wasn't anything to throw me back into the seat.

 

Toyota probably will take it seriously. The dealers is another question. I doubt Toyota fully pays for the dealer's time but some agreed amount and any time spent on these is lost revenue for them. It's all about the $$$$.

 

So you think her rolling through the red light caused this??? If not, then that is a separate issue, isn't it?

 

Isn't the battery being constantly recharged while it is in the ready mode? If so, then all the electric buss would have the right voltage, no?

 

You mean that would cause an acceleration with sufficient force to throw her back into the seat? Really? Or, perhaps that was her imagination too?

 

This isn't how I read the CNN transcript of Blitzer's interview of Wozniak. I read Woz's 'hoax' statement as a lame joke pulled on Blitzer, who ignored the joke and moved on with the interview.

The actual Prius behavior Woz experienced was very real, and different than what others have reported. His case involves what he characterizes as a software bug in the cruise control when pushing the Resume / Increase Speed button many times. But he also acknowledges that others can reasonably characterize it as 'operator error'.

 

Yes, I'd rather not open that can of worms again, but Wozniaks original complaints were real enough to him. His contention being that the media was spinning his concerns into more than he meant them to be, which was probably true. But his trouble reaching Toyota, and his perceived "problem" was real enough to him.

 

As pointed out, Right turn on red permitted
after a full stop, this doesn't seem to have been done. Normal prudent driving, means decelerating before a curve and acceleration slightly thru the curve, which can be done fine in the Prius. As for the OPs problem I have never experienced it. But, I don't doubt thier story.

 

Could be a very good theory! I have been saying since owning my 05, that the 12V battery is PUNY.

 

Steve Wozniak Reports That Prius Issue Is a Big Hoax | Muller Toyota Blog | Clinton NJ Toyota Dealership

I suppose you're free to interpret it as you wish. I'm pretty sure he won a bet. And what he described sounded pretty common if you're driving on a busy highway with your dynamic cruise control.

I did google Woz and Toyota. Looks like he has sudden intended acceleration problems too. Like a $700 fine for going 105 mph in his earlier Prius...

 

As posted earlier, the engine would have been off while making a sharp right turn and braking, especially with temperatures between 70-80F. What time of the day did your wife experience the acceleration. What are the co ordinates or street names where this happened?

Weather Station History : Weather Underground

 

Yes really! This happened while cornering and you can get "thrown" around by centripetal acceleration even if the speed is not changing. That is, just because you're cornering faster than anticipated.

 

I haven't read the whole thread but believe I have an explanation. When cornering, esp. at a fast rate and depending on your braking behavior and other variable, there is a moment where there is a transition from regen braking to regular braking. To new prius owners, based on the reality created by the news, they will believe the car is accelerating. It is more like a lurch.

On a similar note, I find that my traction control kicks in in times when I don't believe it should be and this also causes a lurch. Before anyone says anything about tires, I had Goodyear Comforttread 195/60/15, alignment done, and still had issues. I also believe that new prius owners can become discombobulated at the fact that the engine is running when the battery is full. It may feel like the car is accelerating.

kthxbye

 

That is the item that triggered the misinterpretation here earlier.

I suppose you're free to interpret it as you wish. I'm pretty sure there was no bet. From the CNN transcript:

WOZNIAK: Oh, well, it's a big hoax. I bet my friends I could get on your show, and here I am. It's a big hoax.

Well, the hoax is really more in the media. The media is portraying me as saying, oh, I'm worried about the problem; what they have been recalled for is really a software problem.

I haven't really said those things. They have put those words in my mouth. What I said is, my Prius has a totally different, unrelated problem. It has actually had it two, three months ago. ...

 

Yes, pretty much the same thing happened to me in February 2010. We have a 2004 Prius. I had taken my foot off the accelerator to begin to put my foot on the brake when the car surged out of control. Luckily it was a very leisurely Sunday morning. dry road etc and I was on a city street, not going very fast and had lots of room between me and the car in front which was stopped at a light. As the car sped up I pressed harder and harder on the brake then had to swerve and fishtail to avoid hitting the car in front of me. Somehow I stopped before surging into oncoming traffic.

I wrote everything down thinking Toyota would want to know everything to help diagnosis the problem. Toyota actually said...are you sitting down...I pressed the gas instead of the brake! They didn't want to know anything, all they wanted to do was deny there is any problem. We filed the Claims with the NHTSA but they also don't want any details. They only parrot back the Toyota line which is 1) the floor mat got stuck (we had removed our months before) then 2) you stomped on the gas instead of the brake (well then I'm not sure how the car finally stopped as it was the same pedal I continually depressed).

We heard yesterday from a mechanic friend that there is now a software fix. I called Toyota and got Wesley at Putnam Toyota, the same guy who belittled me in the first place. I asked if there is a software fix. He said he's never heard of a Prius surging out of control. (Again, this is the same guy I originally reported the problem to.) So Toyota's stance is nothing ever happened. And they have the government agencies parroting the exact same story. It's quite frightening.

 

Re: Sudden Acceleration - It Happened To Us Today
Yes, pretty much the same thing happened to me in February 2010. We have a 2004 Prius. I had taken my foot off the accelerator to begin to put my foot on the brake when the car surged out of control. Luckily it was a very leisurely Sunday morning. dry road etc and I was on a city street, not going very fast and had lots of room between me and the car in front which was stopped at a light. As the car sped up I pressed harder and harder on the brake then had to swerve and fishtail to avoid hitting the car in front of me. Somehow I stopped before surging into oncoming traffic.

I wrote everything down thinking Toyota would want to know everything to help diagnosis the problem. Toyota actually said...are you sitting down...I pressed the gas instead of the brake! They didn't want to know anything, all they wanted to do was deny there is any problem. We filed the Claims with the NHTSA but they also don't want any details. They only parrot back the Toyota line which is 1) the floor mat got stuck (we had removed our months before) then 2) you stomped on the gas instead of the brake (well then I'm not sure how the car finally stopped as it was the same pedal I continually depressed).

We heard yesterday from a mechanic friend that there is now a software fix. I called Toyota and got Wesley at Putnam Toyota, the same guy who belittled me in the first place. I asked if there is a software fix. He said he's never heard of a Prius surging out of control. (Again, this is the same guy I originally reported the problem to.) So Toyota's stance is nothing ever happened. And they have the government agencies parroting the exact same story. It's quite frightening.

 

Yes, Toyota the NTSA and the dealer tech were all correct. You hit the gas instead of the brake. Watch this vid to get a better understanding of how the prius brakes work.

 

The software fix doesn't address what you describe. It changes the feel of the transition from regenerative braking to friction braking over a bump. It does not address an actual loss of braking.

In the thousands of posts I have read, this is the first one describing this problem. If it is a real problem, then it is a freak issue relating to just your car, not the Prius in general. If I had to guess at the actual cause, I would have to go with the wrong pedal suggestion.

Tom

 

If the traction light came on it meant the tires were slipping, thus activating the ABS (Anti-locking Brake System), which by design, released the brakes momentarily to "unlock" the wheels. And this unlocking wheels makes the driver feel the car "accelerate". In fact it was only reduced in deceleration. Due to the law of conservation of momentum, the driver's body lurch forward thus the feeling of "acceleration". It's absolutely safe. The fact that the brake picked up the "slack" a split second later proves that.

I don't think a glance of the road surface, especially not expecting anything out of ordinary, would allow the driver to determine with definite accuracy that it "was clean and dry". For example, it might have some minor, unnoticable oil spill that caused the tire slippage.

I experienced a similar "lurch forward" when I was braking before a red light, and the car hit an unexpected bump on the road. It was a split second of "air-born" feeling that scared my heart; but my brain, armed with the knowledge of the matter, took control and did not panic at all.

This happens to ALL CARS with ABS, not just to Prii.