The lead front page article in this morning's Wall Street Journal Focused on Toyota's UA problems and solutions.

Importantly, in that article, there was a report of a significant Prius UA incident. From the details reported, driver error would not be credible, the car did not have the faulty accelerator pedal assembly, and there were no floor mats !!!!

It would seem that there is, indeed, some reason to suspect that causes of UA might be present specifically in the Prius - other than driver error, floor mats or the accelerator pedal assemblies.

 

Based on Wozniak's description of a highly repeatable acceleration when cruise control is engaged, my guess is a gain coefficient in the cruise logic is off. It doesn't have to be off by much to have the calculation go unstable and multiply error rather then drive error to zero as it's intended to. I worked on a very similar sounding issue years ago. It's true once you get into a situation like this it's usually very easy to repeat. And it turned out to be one value was wrong at about the 5th decimal place.

 

This is my posting from 6/27/'07, to show just how far back this goes:

My wife was driving at 40 mph when the engine suddenly begain to over-rev, causing her to nearly lose control. The car quickly accelerated to 60 mph. All this happened on a state hwy which had several "S" curves going downhill.

She was unable to shut engine down using either the power-button, nor could she shift out of drive.

Finally, after the road flattened out, she was able to bring the car to a stop. However, the hard braking resulted in a left, front disk brake fire. The fire was put out by a man who was alongside the road. He was able to run to his house for 2 fire extinguishers.

The event occured on Wisconsin state route 107, approximately 1 mile south of county route J, in the early afternoon. The temperature was approximately 80-85 degrees F.

A short time after the incident, I wanted to test the emergency brake, so I set the emergency, started the car, placed it in Drive, and pushed the accelerator to the floor. All seemed normal.

The Prius was towed to Rosemurgy Toyota in Wausau, Wi.

To date, service is not complete.

However, this is Toyota's explanation:

The Toyota rubber floor mat was against/over/on the accelerator, causing it to be pushed down (here, I was shown a picture which purports to show this).

But, note what I did when I got into the car: I set the brake, pushed the Power Button (engine did not suddenly rev) and I shifted into Drive (could I do that with a reving engine)? Lastly, I pushed down on the accelerator peddle!

There was at least one other incident reported on an '05. Toyota states that what occured on Monday, June 25, 2007 to my '06 Prius had never happened before.

.

 

Martin,

Thanks for repeating your post.

I think I did read it previosly, but not with the attention and interest that I have now that I have definitely had the floor mat problem myself, and now that I have also read of several cases that clearly cannot have been due to either the mats or the CTS pedal assemblies.

I am curious to know - after passage of time and reports of other incidents both with and without credible floor mat explanations:

1. Do you now think that the floor mat could hsave been the cause of your wife's incident ?

2. Did your dealer ever resolve the issue to your satisfaction ?

3. Did you, yourself do anything to eliminate future problems -floor mat or otherwise ?

4. Isn't your car too old to possibly have the CTS pedal assembly upon which Toyota is currently blaming thier problems ?

5. Have you had any more similar incidents ?

Thanks in advance for any info.

Jack

 

1. When the car was returned to us, we tested their assumption (along with their phony pict) and found that, my wife all 5'1" of her was unable to move those floor mats. The all weather mat I bought in '06 at Toyota and fits snugly in the driver's well.

They went a step further actually than the latest recall of mat against pedal. The pict showed the mat draped over the accelerator such that part of the mat was also under the brake pedal. Thus, the story goes, as she stepped on the brake she caused the mat to force the accelerator down.

2. No. Even tho the car was under warranty they refused to honor it. Next stop I thought, the courts. However, my insurance came through in spades so I decided to let State Farm fight it out with Toyota.

3. A friend who free-lanced with Toyota suggested I remove one mat and anchor the one I had in the car. I removed the faux mohair mat and anchored the all-weather mat. However even not anchored, that mat fits so snugly in the driver's well that I cannot move it without lifting it.

I've practiced getting the Prius into neutral, actually pretty easy. Just flick the shift *** to the left and that takes it out of drive. I tried to physically move the shift *** from drive up to neutral. All that did was throw it into reverse. Maybe plan B?

4. Yes. Briefly. However I think this is Toyota shifting the blame. The result is going to send CTS into the tank and Elkhart along with it.

5. No other incidents. My wife refuses to drive on a road narrower than a freeway/expressway or runway.

Additionally, she's had more than the mythic 15 minutes of fame having been mentioned in the second feature article in the LA Times, a TV appearance on Consumer Reports and today a friend emailed me to tell me my wife also had an interview on NPR.

Does she need an agent?

 

Martin,

Thanks for the very full and informative reply.

I'm left thinking that there are likely UA causes not being addressed by Toyota.

The last time, they had identified the mats as a proven problem and then tried to blame incidents like yours on the mats whenever they could.

This time they have identified the faulty pedal assemblies as the cause of some problems and now it looks like they will attribute all of the problems on cars without floor mats to the pedal assemblies.

Kind of unsettling.

 

Now the Transportation Dept is doing a full bore investigation. What will really screw toyota is when my car, or one of my series (II?) takes off.

The last article in the LA Times and the Washington Post have, "experts" stating it's probably software. And the House committee doing the investigation which will air on the 25th on C-SPAN hammered Toyota for telling the public one thing and the House staff something else, mainly, Toyota doesn't have a clue.

Wonder when they'll figure out the brake override.

 

I haven't come back for some time because of various reasons.
However, when I first had my Woody the 2007 Prius, I combed through various Prius Hybrid message boards in addition to the one here, discussed with Bob.

There were several reports in north regions in US and Canada, that Prius does seems to have problem to STOP and some might accelerate unintended, one lady even had a big hole at her garage when her Prius went through the wall.

I even experienced once but minor brake issue on a heavy rain day, I was lucky, I just skid and went to the road side without causing any major accident last year. However, I am unable to duplicate the same problem and I am glad I couldn't because it can be dangerous.

It indeed is a bit disturbing, because we do not know under exactly what kind of circumstances, our beloved Prius might decide to go wild and speed. I certainly hope Toyota can fix that so-called software bug / time delay, whatever they believe the problem is.

At the end of the day, no matter how much we pay for the car or how good the MPG is for the car, we want to get home in one piece.

Maybe I did not really reply the post head on, but I do have doubts on the Prius Brake system, not just for the 3G only, the problems do go back to 2G.

 

My wife and I have concluded that Toyota is clueless.

They're grasping at whatever comes to hand. Floor mat/accelerator, accelerator malfunction. Headlight problem? You're using them too much.

And of course, Toyota refuses to handle these complaints under warranty. To do so opens them up to being responsible.

The result is we're left with the hope that whatever caused the problem doesn't surface again.

My '06 Prius has 60,000 miles on it. This summer we're planning a drive into Quebec, Canada. Probably over 5,000 miles more. Always in the back of our minds, "Is it going to happen again?"

 

Yes, Toyota is clueless, TOTALLY.

If the firmware is found to be at fault that will put the blame on NipponDenso/Denso US's doorstep. So I doubt if Denso is being very cooperative in trouble-shooting this issue.