Acceleration Problem On Our 2010 Prius Gen V

It will be interesting to hear what your dealer determines. Please advise the post on the results. I too, drive a PRIUS, V, so am interested as well as the other posters on this site.

I have NOT experienced any issues thus far in 3 1/2 months.

We await your findings.

 

Is this over bumpy or broken pavement? Your description sounds a lot like the ABS issue.

Tom

 

That was my first thought, but it isn't. It happens whether the engine is on or not. Also, even if the engine's off, it doesn't happen if I go straight.

Anyway, it sounds like the OP is talking about the brake issue.

 

The three times I have experienced the "ABS issue" I have been on a rough road at low speed and braking a bit harder than normal. But I agree this sure does sound like it, and others have reported it on smooth pavement. Could be?

SteveB, it will be interesting to find out what your dealer says.

 

My wife just described the same to me tonight. She was braking and all of the sudden she experienced a sudden acceleration. She was surprised and was caught off gaurd when it happened.

Have you communicated this to a dealer service technician?

 

It's like skidding on ice, you are not accelerating faster, you just feel like you are going faster!

See why I believe the hung throttle problem were due to bad drivers, not bad cars

 

I too have detected this, and from what I can tell, it does appear to be ABS/Friction Brake related. I don't "Believe" it's a defect or problem, because I have noticed this in other cars, maybe just more noticeable in the Prius.

I was on a road, going over a bridge and where that bridge section met the road was a space. That space happened to be just about where I was going to apply the brakes to stop for a red light, car's ahead of me.

As I was braking at about 12 MPH and hit that space/gap in the road, my car fealt like it was on OIL. But all I did was apply the brakes a bit harder and all was well and I didn't accelerate or slam into anyone!

But I do think the perception makes one "appear" they are accelerating. It does catch you off guard...but since I had this only one time prior, I was able to do what I did then, apply the brakes harder.

At the same time I did note my engine was off, so maybe that's why we notice it more in the Prius as opposed to a standard ICE vehicle.

Wonder if that "Phenomenon" would be the same in a PHEV??

 

I believe there are three reasons this is more noticeable in a Prius:

1) Most normal braking is done regeneratively. The transition to friction ABS braking adds time to the event.

2) The Prius traction control and ABS system is touchier than most.

3) The LRR tires shipped with Prius do not provide the best traction.

The phenomenon should be the same in a PHEV Prius. The extra weight might make it a bit worse.

Tom

 

You can get an FJ to replicate that too. I believe that the way Toyota does their ABS programming may influence the behavior on those surfaces

 

I've experienced a different acceleration problem. When I start my car and put it into reverse to back out of my garage, it suddenly lurches into acceleration. I have my foot on the brake when I shift into reverse and when I take my foot off the brake it does this. I have to slam on the brakes to stop the car. It also has done it when I shift into drive. This is an intermittent problem so the dealer, OF COURSE, has no idea what I'm talking about since it never does it when I'm at the dealership. I'm ready to get rid of my 4 month old Prius IV and get something less dangerous.

 

I think regenerative braking cuts out if your making a turn above a certain speed...

I've noticed on my car that on certain highway exit ramps, when deaccelerating from 55mph to 40mph (beginning to turn here) regenerative braking cuts out after i start turning.

 

I am truly amazed that there are people out there that can deny what those of us who have purchased the 2010 Prius are experiencing! When I go over rough road/pot holes, etc., and I am braking, 9 out of 10 times my car will accelarate and I must jam my foot harder on the brake pedal where it is already supposedly applying slowness to my car!!!!!! This can not be normal!!!!! And, like the other owners, I have just adjusted my driving techniques to accommodate this problem with my Prius 2010, but what happens when i'm not paying 110% attention, which most of us aren't when we are going slower and coming to what we think is supposed to be a stop????? And that kid runs out at the intersection, or the bicycler starts flying across the intersection??? I've come close to both because of this very problem. Then what????? I live in Houston, TX, and the roads here, especially in the right hand lanes are absolutely horrible with rough road and potholes. They are what they are, but who is to take responsibility for this newest hiccup with the Prius 2010 vehicles????? I really like my car, but.....

Also, where is this close to 50mpg that I am supposed to be getting?????? I have had my Prius now since September, 2009. I am lucky if I get 42mpg. Why is that???? Anyone know????

 

No one is denying your braking experience. We do deny, however, that your Prius accelerates during braking. It simply doesn't do that. I'm not going to write the whole explanation again, as it has been posted many times, but in short, the loss of braking action is interpreted by humans to be acceleration. It's a loss of deceleration, not acceleration.

I'm sure it makes no difference to you, as you will see this distinction as weasel wording or simply playing with words, but to an engineer there is a whole world of difference.

As for your mileage, you may want to pose that question to the EPA. The EPA tests determine the official mileage figures. Your 42 mpg simply means your driving profile is different than the one used by the EPA. Some people do better, some do worse. Your mileage may vary (where have I heard that before?).

Tom

 

Yup!

I have two commutes. One with hills and one with out. With hills I get 44mpg avg. in winter without hills I get 50mpg avg. in winter. Conditions will vary your MPG so to expect 50mpg in any kind of conditions and driving patterns is rather naive.

 

I don't think this is the reason the don't use ABS for racing. They outlawed it in Formula One because it made the cars brake to good. They also are outlawing traction control, because it made racing to sterile.

 

Oh please, its not that bad. I live in Houston and the roads aren't anywhere like you describe them. Sure there are some roads that are in bad shape but the majority of roads are perfectly fine. And any really severe potholes are filled up by the city pretty quickly.

 

Nobody appears to be debating that there is a strange braking experience that is NOT normal and must be explained by Toyota. Whether there is actual acceleration or not, there is definitely a strange sensation of acceleration when I drive over rough pavement, potholes, etc. I like my Prius, but I want this problem to be addressed by Toyota in a straight forward manner. I would like to approach Toyota with some meat (other people with similar experiences). We cannot all be hallucinating or imagining a problem. Please e-mail me at [email protected] to provide me your contact name, number, email and share your experience. Thanks.

 

They also banned turbine engines and four wheel drive for the same reason. Remember Parnelli Jones in the 1967 Indy 500? He easily dominated the race driving a car powered by a Pratt & Whitney turbine. Only a failed bearing late in the race kept him from winning. Indy banned turbines after that.

In bicycle racing recumbent bicycles were likewise banned.

Tom