Prius unintended acceleration
#11
02-05-2010, 05:10 PM
Re: Prius unintended acceleration
I forgot I took a slug of picts to show how outrageous Toyota's contention telling us the cause was the mats. I gave those to the reporters also.
Options for companies which find that a product is finally defective - especially one selling for 30,000.00 bucks reflexively is to duck and cover. It takes the realization that finally that's not going to work.
For this, I (we) must thank Ralph Vartabedian and Ken Bensinger of the LA Times who started serializing the Toyota's problems back in Nov. of '09.
Last edited by centrider; 02-05-2010 at 05:14 PM. Reason: clarification.
#12
02-05-2010, 08:48 PM
Re: Prius unintended acceleration
I have a 2010 Prius with 6500 miles on it.
Today as I was going down a slight hill and approaching a red light, so I gently applied brake pedal pressure to utilize the regenerative braking. The Prius was slowing smoothly through about 15 MPH when my right wheels passed over a man-hole cover which caused a slight bump. At that moment my braking ceased for about a second or two. It was very sudden and I immediatly increased the pedal pressure and the car stopped with the normal brakes.
The initial loss of braking was so total that it made it feel like the car accelerated during that one or 2 seconds. I suspect that was due to the sudden total loss of deceleration.
This event caused me to remember that I experienced a similar sensation once before. I was coming up to a stop sign about a block from my house when my right wheels passed over a 10 to 15 foot patch of ice. The braking immediatley ceased for one or two second and then came back on.
It was a little un-nerving since I was in the process of stopping at an intersection and the front of the car passed the stop sign and entererd the cross road by about 10 feet. Fortunatley the crossing traffic was about 150 feet from my position and had plenty of room to avoid the front of my car.
I thought that it was the anti-skid that caused that event.
Today as I was going down a slight hill and approaching a red light, so I gently applied brake pedal pressure to utilize the regenerative braking. The Prius was slowing smoothly through about 15 MPH when my right wheels passed over a man-hole cover which caused a slight bump. At that moment my braking ceased for about a second or two. It was very sudden and I immediatly increased the pedal pressure and the car stopped with the normal brakes.
The initial loss of braking was so total that it made it feel like the car accelerated during that one or 2 seconds. I suspect that was due to the sudden total loss of deceleration.
This event caused me to remember that I experienced a similar sensation once before. I was coming up to a stop sign about a block from my house when my right wheels passed over a 10 to 15 foot patch of ice. The braking immediatley ceased for one or two second and then came back on.
It was a little un-nerving since I was in the process of stopping at an intersection and the front of the car passed the stop sign and entererd the cross road by about 10 feet. Fortunatley the crossing traffic was about 150 feet from my position and had plenty of room to avoid the front of my car.
I thought that it was the anti-skid that caused that event.
#13
02-05-2010, 11:01 PM
Re: Prius unintended acceleration
I have a 2010 Prius with 6500 miles on it.
Today as I was going down a slight hill and approaching a red light, so I gently applied brake pedal pressure to utilize the regenerative braking. The Prius was slowing smoothly through about 15 MPH when my right wheels passed over a man-hole cover which caused a slight bump. At that moment my braking ceased for about a second or two. It was very sudden and I immediatly increased the pedal pressure and the car stopped with the normal brakes.
The initial loss of braking was so total that it made it feel like the car accelerated during that one or 2 seconds. I suspect that was due to the sudden total loss of deceleration.
This event caused me to remember that I experienced a similar sensation once before. I was coming up to a stop sign about a block from my house when my right wheels passed over a 10 to 15 foot patch of ice. The braking immediatley ceased for one or two second and then came back on.
It was a little un-nerving since I was in the process of stopping at an intersection and the front of the car passed the stop sign and entererd the cross road by about 10 feet. Fortunatley the crossing traffic was about 150 feet from my position and had plenty of room to avoid the front of my car.
I thought that it was the anti-skid that caused that event.
Today as I was going down a slight hill and approaching a red light, so I gently applied brake pedal pressure to utilize the regenerative braking. The Prius was slowing smoothly through about 15 MPH when my right wheels passed over a man-hole cover which caused a slight bump. At that moment my braking ceased for about a second or two. It was very sudden and I immediatly increased the pedal pressure and the car stopped with the normal brakes.
The initial loss of braking was so total that it made it feel like the car accelerated during that one or 2 seconds. I suspect that was due to the sudden total loss of deceleration.
This event caused me to remember that I experienced a similar sensation once before. I was coming up to a stop sign about a block from my house when my right wheels passed over a 10 to 15 foot patch of ice. The braking immediatley ceased for one or two second and then came back on.
It was a little un-nerving since I was in the process of stopping at an intersection and the front of the car passed the stop sign and entererd the cross road by about 10 feet. Fortunatley the crossing traffic was about 150 feet from my position and had plenty of room to avoid the front of my car.
I thought that it was the anti-skid that caused that event.
I'd be interested to here what your dealer says. Also check out the NHTSA website and recent newspapers. My info comes from the LA Times and the Washington Post.
Good Luck. Oh, file a report with the NHTSA (www.nhtsa.gov).
#14
02-06-2010, 07:00 AM
Ridiculously Active Enthusiast
Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Prius unintended acceleration
I have a 2010 Prius with 6500 miles on it.
Today as I was going down a slight hill and approaching a red light, so I gently applied brake pedal pressure to utilize the regenerative braking. The Prius was slowing smoothly through about 15 MPH when my right wheels passed over a man-hole cover which caused a slight bump. At that moment my braking ceased for about a second or two. It was very sudden and I immediatly increased the pedal pressure and the car stopped with the normal brakes.
The initial loss of braking was so total that it made it feel like the car accelerated during that one or 2 seconds. I suspect that was due to the sudden total loss of deceleration.
This event caused me to remember that I experienced a similar sensation once before. I was coming up to a stop sign about a block from my house when my right wheels passed over a 10 to 15 foot patch of ice. The braking immediatley ceased for one or two second and then came back on.
It was a little un-nerving since I was in the process of stopping at an intersection and the front of the car passed the stop sign and entererd the cross road by about 10 feet. Fortunatley the crossing traffic was about 150 feet from my position and had plenty of room to avoid the front of my car.
I thought that it was the anti-skid that caused that event.
Today as I was going down a slight hill and approaching a red light, so I gently applied brake pedal pressure to utilize the regenerative braking. The Prius was slowing smoothly through about 15 MPH when my right wheels passed over a man-hole cover which caused a slight bump. At that moment my braking ceased for about a second or two. It was very sudden and I immediatly increased the pedal pressure and the car stopped with the normal brakes.
The initial loss of braking was so total that it made it feel like the car accelerated during that one or 2 seconds. I suspect that was due to the sudden total loss of deceleration.
This event caused me to remember that I experienced a similar sensation once before. I was coming up to a stop sign about a block from my house when my right wheels passed over a 10 to 15 foot patch of ice. The braking immediatley ceased for one or two second and then came back on.
It was a little un-nerving since I was in the process of stopping at an intersection and the front of the car passed the stop sign and entererd the cross road by about 10 feet. Fortunatley the crossing traffic was about 150 feet from my position and had plenty of room to avoid the front of my car.
I thought that it was the anti-skid that caused that event.
If ABS detects IMPENDING (the wheel's rotational rate declining so rapidly it will undoubtedly soon reach lockup) lockup of a braking wheel it will immediately disable regen braking. But in a normal case frictional braking coming online should occur with a 100 or so milliseconds.
ABS is designed to control hydraulic braking, not regen.
Oops, sorry, just noticed. Both of your events seem to have to do with disparate right/left roadbed traction. I don't at the moment remember the details but I think I have read that this is an unusual ABS/TC/VSC situation. If a serious level of braking were allowed to continue on the wheel remaining with traction the car might well end up "skidding" off in the direction of the tractive wheel.
So what you experienced might well have been SOP.
Last edited by wwest; 02-06-2010 at 07:08 AM.
#15
02-06-2010, 08:11 AM
Join Date: Apr 2008
Location: Houston, Texas
Posts: 373
Re: Prius unintended acceleration
Fox news (ch 11) just left after interviewing my wife. It will air at 7 p.m. local, Sun.
I forgot I took a slug of picts to show how outrageous Toyota's contention telling us the cause was the mats. I gave those to the reporters also.
Options for companies which find that a product is finally defective - especially one selling for 30,000.00 bucks reflexively is to duck and cover. It takes the realization that finally that's not going to work.
For this, I (we) must thank Ralph Vartabedian and Ken Bensinger of the LA Times who started serializing the Toyota's problems back in Nov. of '09.
I forgot I took a slug of picts to show how outrageous Toyota's contention telling us the cause was the mats. I gave those to the reporters also.
Options for companies which find that a product is finally defective - especially one selling for 30,000.00 bucks reflexively is to duck and cover. It takes the realization that finally that's not going to work.
For this, I (we) must thank Ralph Vartabedian and Ken Bensinger of the LA Times who started serializing the Toyota's problems back in Nov. of '09.
#16
02-06-2010, 08:56 AM
Re: Prius unintended acceleration
That will be nationally. They flew out from snow in NY city to pouring-down rain in Long Beach.
By the way, another article in the LA Times, front page, about the Toyota president getting fried by Japanese reporters. Also mentioned was that cars coming in with the, "defective" [my quotes] floor mats will get the brake-accelerator over ride installed and the current problem with the '10 Prius and it's momentary lose of brakes.
Phew
Also finally got our incident into NHTSA yesterday.
By the way, another article in the LA Times, front page, about the Toyota president getting fried by Japanese reporters. Also mentioned was that cars coming in with the, "defective" [my quotes] floor mats will get the brake-accelerator over ride installed and the current problem with the '10 Prius and it's momentary lose of brakes.
Phew
Also finally got our incident into NHTSA yesterday.
Last edited by centrider; 02-06-2010 at 09:02 AM. Reason: clarification
#17
02-06-2010, 08:59 AM
Join Date: Apr 2008
Location: Houston, Texas
Posts: 373
Re: Prius unintended acceleration
Thanks.
I'll be sure to catch it !
#18
03-10-2010, 06:11 PM
Re: Prius unintended acceleration
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.
.
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.
.
"She was unable to shut engine down using either the power-button, nor could she shift out of drive."
- Do you know that it is necessary to press and hold the "Power" button down for 3 seconds in order to turn off the engine? Did your wife hold down the button for at least 3 seconds?
- Why couldn't she shift out of Drive? It is very easy to shift the Prius since it is only an electronic switch -- just push the shift **** to the left for a second and it will go into Neutral. Or push it into Reverse and it will go into Neutral. Or push the Park button and it will go into Neutral. Even at 60 mph.
- It does sound like extraordinary braking was needed. That points to a real problem.
- Why was she able to stop the car when the road leveled out? Did the unintended acceleration stop then?
- The Prius has a kind of brake override built in as a result of the hybrid system software. If both the accelerator pedal is pushed and the brake is pushed, the brake takes precedence and the engine power drops to idle. I wonder why this didn't happen for your wife?
- I don't understand this test. You are describing how the Prius normally operates. If you sit in your driveway with the car in Park and press the accelerator pedal, it will not cause the engine to rev significantly (maybe a little bit).
- If you set the emergency brake, then put it in Drive, I'm thinking this will just act like the brake override or like the car sitting in Park, and the engine power will not go much above idle or slight revving. I will test this in my car when I get a chance. I have tested the brake override in both my 2002 Prius and my 2008 Prius, and it works consistently.
FYI In case you haven't seen this information, it may be helpful:
http://pressroom.toyota.com/pr/tms/t...al-152196.aspx
#19
03-10-2010, 09:23 PM
Re: Prius unintended acceleration
I appreciate your retelling this experience that your wife had. I don't quite understand some things, though.
"She was unable to shut engine down using either the power-button, nor could she shift out of drive."
FYI In case you haven't seen this information, it may be helpful:
http://pressroom.toyota.com/pr/tms/t...al-152196.aspx
"She was unable to shut engine down using either the power-button, nor could she shift out of drive."
- Do you know that it is necessary to press and hold the "Power" button down for 3 seconds in order to turn off the engine? Did your wife hold down the button for at least 3 seconds?
- Why couldn't she shift out of Drive? It is very easy to shift the Prius since it is only an electronic switch -- just push the shift **** to the left for a second and it will go into Neutral. Or push it into Reverse and it will go into Neutral. Or push the Park button and it will go into Neutral. Even at 60 mph.
- It does sound like extraordinary braking was needed. That points to a real problem.
- Why was she able to stop the car when the road leveled out? Did the unintended acceleration stop then?
- The Prius has a kind of brake override built in as a result of the hybrid system software. If both the accelerator pedal is pushed and the brake is pushed, the brake takes precedence and the engine power drops to idle. I wonder why this didn't happen for your wife?
- I don't understand this test. You are describing how the Prius normally operates. If you sit in your driveway with the car in Park and press the accelerator pedal, it will not cause the engine to rev significantly (maybe a little bit).
- If you set the emergency brake, then put it in Drive, I'm thinking this will just act like the brake override or like the car sitting in Park, and the engine power will not go much above idle or slight revving. I will test this in my car when I get a chance. I have tested the brake override in both my 2002 Prius and my 2008 Prius, and it works consistently.
FYI In case you haven't seen this information, it may be helpful:
http://pressroom.toyota.com/pr/tms/t...al-152196.aspx
The Prius was an '06, so don't know if there was a brake override, in fact I'm pretty sure there wasn't any.
I was the primary driver on the Prius - it was my car. (When did you find that holding the start/stop for 3 sec would shut off the engine?) She did hit the button, but even holding in for an extended period didn't shut it down. How long was that? Who knows?
I've recently (after reading about all this in the LA Times) tried putting the car into neutral. It does take the presence of mind to move the shift from its at rest position to neutral - and hold it. Just pushing it to neutral means it will pop back into drive.
Keep in mind in addition to trying to (a) stop the car, (b) shut off the engine, (c) shift out of drive - and that must be the most counter-intuitive aspect - she was maneuvering the car around cyclists and into oncoming traffic. on a two lane country road. (Hitting any of those riders would have put her away as no one would believe that the car just ran away).
Back to the assumption of brake override: Why then were the brakes burned out? Something happen to the over ride? Or no override?
The car stopped because of the fact she stomped on the brake pedal with both feet and held them there until the car finally stopped. You can say the brake override worked but not before the brakes burned up. If you live in the Long Beach area, stop by and I'll show you the brakes.
What I did seemed to put to rest Toyota's picture/assumption that the floor mat was up and over the accelerator pedal and under the brake pedal. If their assumption was correct, starting the Prius would have seen the engine rev.
Whatever the Prius did earlier was no longer happening when I got to it.
Finally, see the story of the past two days of the '08 Prius on the 10 E of San Diego.
Finally, my Prius has 61,000 miles. We're going up to E. Canada this summer. I always in my imagination, have my fingers crossed.
By the way, Toyota sells cars. Keep that in mind as you read their press releases.
Last edited by centrider; 03-10-2010 at 09:40 PM. Reason: spelling and clarity
#20
03-10-2010, 09:50 PM
Re: Prius unintended acceleration
Keep the following in mind:
The Prius was an '06, so don't know if there was a brake override, in fact I'm pretty sure there wasn't any.
CZ-1: All Prius from the Generation 1, 2001-03, Generation 2, 2004-2009, and Generation 3, 2010--, have this "brake override." I own a 2002 (Gen 1) and 2008 (Gen 2) and have tested it on both.
I was the primary driver on the Prius - it was my car. When did you find that holding the start/stop for 3 sec would shut off the engine? She did hit the button, but even holding in for an extended period didn't shut it down. How long was that? Who knows?
CZ-1: That's the just the normal instructions that Toyota has always given for it. It's meant to keep people from accidentally shutting off the engine. Go figure it would work against safety.
I've recently (after reading about all this in the LA Times) tried putting the car into neutral. It does take the presence of mind to move the shift from its at rest position to neutral - and hold it. Just pushing it to neutral means it will pop back into drive.
CZ-1: Agreed--it does takes presence of mind to take specific actions. That's why astronauts train for years to enable them to respond to emergencies if needed, so it's definitely not easy. The shift **** will pop back over to the right, but the shift indicator on the dash will show Neutral and it will stay in Neutral if it was held there for a second or so. Some other owners who have tested these things say that the fastest/easiest way to put the car into Neutral is to shift into Reverse or even press the Park button. Both of these immediately put the car into Neutral. (Don't hit Park unless you are above 6 mph, otherwise it will also try to actually put the parking pawl on.) I've used the Reverse method, and it works.
Keep in mind in addition to trying to (a) stop the car, (b) shut off the engine, (c) shift out of drive - and that must be the most counter-intuitive aspect - she was maneuvering the car around cyclists and into oncoming traffic. on a two lane country road.
Back to the assumption of brake override: Why then were the brakes burned out? Something happen to the over ride? Or no override?
CZ-1: Yes, that's the part that points to your car having a real problem. The brake override didn't work as it should have, and the brakes had to be used so hard that they caught on fire. It definitely says that something failed, maybe multiple somethings.
What I did seemed to put to rest Toyota's picture/assumption that the floor mat was up and over the accelerator pedal and under the brake pedal. If their assumption was correct, starting the Prius would have seen the engine rev.
Whatever the Prius did earlier was no longer happening when I got to it.
CZ-1: I guess if nothing had been touched or moved or anything, that's true, your test would have shown that physically it wasn't the floor mat. Sorry, I get it now.
I was still curious about why or how the unintended acceleration stopped. I guess that would be hard to figure out at this point. Thanks for putting up me. Sorry to dredge up an old issue.
The Prius was an '06, so don't know if there was a brake override, in fact I'm pretty sure there wasn't any.
CZ-1: All Prius from the Generation 1, 2001-03, Generation 2, 2004-2009, and Generation 3, 2010--, have this "brake override." I own a 2002 (Gen 1) and 2008 (Gen 2) and have tested it on both.
I was the primary driver on the Prius - it was my car. When did you find that holding the start/stop for 3 sec would shut off the engine? She did hit the button, but even holding in for an extended period didn't shut it down. How long was that? Who knows?
CZ-1: That's the just the normal instructions that Toyota has always given for it. It's meant to keep people from accidentally shutting off the engine. Go figure it would work against safety.
I've recently (after reading about all this in the LA Times) tried putting the car into neutral. It does take the presence of mind to move the shift from its at rest position to neutral - and hold it. Just pushing it to neutral means it will pop back into drive.
CZ-1: Agreed--it does takes presence of mind to take specific actions. That's why astronauts train for years to enable them to respond to emergencies if needed, so it's definitely not easy. The shift **** will pop back over to the right, but the shift indicator on the dash will show Neutral and it will stay in Neutral if it was held there for a second or so. Some other owners who have tested these things say that the fastest/easiest way to put the car into Neutral is to shift into Reverse or even press the Park button. Both of these immediately put the car into Neutral. (Don't hit Park unless you are above 6 mph, otherwise it will also try to actually put the parking pawl on.) I've used the Reverse method, and it works.
Keep in mind in addition to trying to (a) stop the car, (b) shut off the engine, (c) shift out of drive - and that must be the most counter-intuitive aspect - she was maneuvering the car around cyclists and into oncoming traffic. on a two lane country road.
Back to the assumption of brake override: Why then were the brakes burned out? Something happen to the over ride? Or no override?
CZ-1: Yes, that's the part that points to your car having a real problem. The brake override didn't work as it should have, and the brakes had to be used so hard that they caught on fire. It definitely says that something failed, maybe multiple somethings.
What I did seemed to put to rest Toyota's picture/assumption that the floor mat was up and over the accelerator pedal and under the brake pedal. If their assumption was correct, starting the Prius would have seen the engine rev.
Whatever the Prius did earlier was no longer happening when I got to it.
CZ-1: I guess if nothing had been touched or moved or anything, that's true, your test would have shown that physically it wasn't the floor mat. Sorry, I get it now.
I was still curious about why or how the unintended acceleration stopped. I guess that would be hard to figure out at this point. Thanks for putting up me. Sorry to dredge up an old issue.
