acceleration over uneven road surface while braking

Laird, what time frame are you talking about? How many miles are on the car? How long have you had it? How long has it been since the software fix?

As I have said in another thread, after I had my fix done, the occurence rate dropped about 50% and severity by about 50%. Three months after, I have had no recurrences.

Before the fix, I used to use the brake slip as a signal that I was driving/braking too hard for the situation the car was in, so I considered it a safety feature not a hazard. Now I've lost my feedback. One man's medicine is anothers poison...

 

I notice that the title had been changed. The word "slingshot" had been deleted. How? can a member change that? or did a moderator changed that?

When I search "slingshot" the hits still point to this thread.

If you changed (or made the request to change) the title deleting the word "slingshot", Mr. (or is it Dr.?) Banks, thank you. It takes a good man to admit a mistake.

I also want to extend my apologies to you for reacting too extremely to your original title thinking you are a troll trying to discredit the Prius with "unscientific rumours".

Best wishes.

TL

 

Many years ago I had the opportunity to get involved with NYS Lemon Law. It was a surprisingly fair and uncomplicated proccess. I got a full refund on a one year old Mercury Sable.
The bottom line is this.

If the dealer says there is no problem and you say there is then it is up to you prove there is a problem. The people from the state will want you to show documentation about your repair requests. If I remember correctly there needs to be at least four attempts in the first 18.000 miles by the dealer to repair the problem. Then they will want to know if you can show them or reproduce the problem. In your case they will get in the car with you.

If you are able to find a spot where the problem occurs you will get the attention of the folks from the state because of how it FEELS. So far things are looking good for you. BUT at that point the dealer will whip out his documentaion on this particular braking issue. The documentation will state that your car operates as intended. That there is a very small minority of drivers who cannot understand that regardless of how it feels, what is actually happening is not acceleration but less deceleration.

Now the pooch is screwed...The car is operating as intended without flaw. Granted you may not like it and you may feel unsafe. But how you feel about how the brakes work does not make it a flaw with your particular vehicle or a general design problem or unsafe. You wont be able to return the vehicle under the NYS lemon law because YOU dont like the way the brakes work on an uneven surface.

On the other hand if you can prove that your car is actually accelerating while your stepping only on the brake and there have been at least three attempts by the dealer to fix it, then go for it because under the NYS lemon law you WILL get a full refund.

 

Bravo, case closed!

 

New York, New York. Its a hell of a town.

 

The Bronx is up and the Battery's down.

Tom

 

Hmm, let me think. Doctor. New York. Head up behind. This sounds vaguely familiar...

 

I'm looking forward to it.

We have a lot of road work going on around Huntsville and they tear up the old pavement with a ridge-cutting machine. It is the closest we come to a washboard surface. The other night I tried multiple times to replicate brake fade without any luck. However, it was dry and earlier testing for the SSC-A0B patch indicated a slippery surface, rain/drizzle wetted, was a precondition. One poster reported 'steel plates' were involved in her incidents. So I'm looking forward to understanding your driving conditions.

BTW, if your location is available via Google 'street view,' that might help too. Many of the photos came from Google as opposed to those who were gracious enough to take JPEG photos of the locations.

Thanks,
Bob Wilson

 

Bob,

It does it to me when only ONE wheel goes in a pothole/over a bump, so i wouldn't expect it on your ridged road.

 

One of our Canadian friends reported it happened on a rough road, a detour, and claimed he'd lost all braking. This is significantly different than the single wheel symptom, one that I'm not looking at currently.

The reason I can't really look at a single wheel, pothole is more metrics than anything else. My accelerometer handles three linear axis, not rotational motion (aka., gyroscope.) With out all six degrees of motion, I can't even begin to know what goes on in asymmetrical braking conditions (aka., when the car wants to veer into the ditch or on-coming traffic lane.)

Bob Wilson

 

I think you need loose gravely, I have only felt one time and the road had gravely on it

 

Are you certain that ABS does not activate?

The Prius ABS is unusual in that the brake pedal does not pulse when ABS is activated. Nor is there any audible warning. The only indication that ABS is activated is that the yellow 'skid' light flashes. That's it.

The warning beeper sounds along with the skid light flashing when VSC is activated.

If you find that ABS activates frequently over certain road features, plan to brake earlier and less hard.

 

Mike mentioned something that caught my attention. I don't think anyone has indicated that this issue happened when they applied the brakes hard. Only when they ride the brakes gently (switch over from regen to friction). Would be interesting to find out if anyone lost braking (feel) while pressing hard (initially).

 

Yeah I just experienced a sudden acceleration while i was braking yesterday with my Prius i think i was driving on an uneven road too. Prius is a just a piece of junk. The only thing i like about the prius is the look, and Gas mileage. I dislike driving this car because maybe i like more comfortable cars with a better drive.

 

I've herd of the car loosing braking for a half of a second, but never accelerating. I know it might feel like acceleration, but it's not, but I won't sit here and tell you for sure that it's not because anything is possible. This feeling of the car lurching forward while you hit a pothole in the process of braking happens because as you know, the Prius has regenerative braking, so when it hits a bump, it slips for a second. For example, in a car with a manual transmission, when your downshifting and slowing down with the shifting instead of the brakes and you run over a pothole, the same thing happens with them too. This is nothing new really, this happens to a lot of cars, mostly manuals.

 

I suppose piece of junk is a subjective term and one that cannot be objectively disputed but I actually think the Prius is an evolutionary step above the majority of other cars out there, and for such a low price this makes it especially impressive.

 

Oh Boy, I haven't checked this forum in awhile and the first thing I see is this braking crap again!

Mr. Banks, here's the deal, Your Prius is equiped with a rare Toyota feature for your comfort and well being. It uses sensor technology stolen from NASA that was used on the Lunar Rover.

You see, when the car senses you are on rough road it speeds its self up to get you past the rough patch. This feature keeps you from scrambling your brains which are in some peoples nice person. You were covertly screened at the dealer where you purchased your Prius and it was noted that your brain is in your nice person. You should be thank full that this feature is available for people of your status.

 

Harsh, but I share your sentiment. It amazes me that people do so little research not only before posting but before buying a piece of technology that they are going to entrust their lives with.