Stuck accellerator

Something does not smell right. I smell bait with an after taste of troll.

 

<div class='quotetop'>QUOTE(TheForce @ Aug 13 2007, 06:36 PM) [snapback]495010[/snapback]</div>

'nuff said.

 

Accellerators only stick with teenage or senior citizen drivers. I wonder why that is?

 

<div class='quotetop'>QUOTE(Winston @ Aug 13 2007, 04:05 PM) [snapback]495024[/snapback]</div>

and with people with only one post...

hmmm?

 

<div class='quotetop'>QUOTE(John R. @ Aug 13 2007, 05:08 PM) [snapback]494991[/snapback]</div>

There have been intermittent reports but no one has been able to reproduce this at will. The current working hypothesis is sticking to the carpet . . . somehow. But again, it is an untested hypothesis.

As for shifting, with the exception of "P", this is always safe and in particular "N" will cause the car to start coasting and the engine to drop down to idle. If you ever have a run-away, just shift into "N".

When I get a chance, I plan to rent a 2004-current, NHW20 Prius and see if I can find any way to recreate this problem. I'll also, in the interest of science, floor the accelerator and push "N" to verify it works just like it does on my NHW11, 2003 Prius.

The transmission of the Prius has one major gear, no clutch and is completely computer controlled. You can not break it by shifting a run-away Prius into "N". If it perfectly safe to try this anytime you want at any speed you want. We just don't recommend using "N" going down a steep grade . . . for obvious and subtle technical reasons.

GOOD LUCK!

Bob Wilson
ps. Can you let your daughter perhaps post a first person account of what happened?

 

Hi John R.,

The most probable cause is that the floor mats were not hooked into the holes in the floor that the supplied clips plug into. Read the instruction manual on the installation of the driver side floor mat. There should be two plastic clips stuck into the holes. If you do not have these, remove the front driver's side floor mat, and go to your Toyota dealership and buy the clips.

Constantly pushing on the floor mats, moves them forward till they snag down the gas pedal. Of course, nobody wants to look down while in a traffic situation with a stuck accellerator. And getting out of the car might pull the mat back, as one pulls on ones feet to stand up.

 

<div class='quotetop'>QUOTE(John R. @ Aug 13 2007, 06:08 PM) [snapback]494991[/snapback]</div>

The Prius gas pedal has one big indestructible steel spring and a very small sensor housing with TWO independent postion sensors. This sensor housing is arranged so it is unable to hang the spring. I have an extra Prius gas pedal in my lap and it is clear that only something very strong external to the pedal can keep it from springing back. A loose floor mat will be hard pressed to bind this down. Check for yourself and you can see firsthand. If the spring did not break, then either there was something on the floor that snagged it, or two independent sensors failed simultaneously and temporarily, or there is confusion about exactly what happened. You are in the best postion to find out.

When things go unexpected for a young driver, the gas pedal or the brakes end up being blamed. I know. I nearly took down my parents house pushing the wrong pedal at a very young age.

 

I have had this happen to me twice on my 2008 prius. About a month ago I had it happen just as I got off the highway. Had to turn off the car using the power button to get it to stop. Then when I turned it back on everything was ok till the other day when it happened to me again. When it happened this time I turned the car off and turned it back on still tring to continue to run. I then turned it off again and let it sit for 2 minutes and it came back ok. I took it to the dealer and they checked the cars computer and could not find anything on this. They are blameing it on my weather tech floor mats. I don't think that is remotely possible. Has anyone else seen this and found a good solution to this issue.

Thanks
John Shaffer

 

jshaffer,

I drive an '08, and you got my attention.

The only other report in the last year of a stuck accelerator is the Original
Poster in this thread. And that died with a whimper when the OP didn't
repost. It looked like an incident of trolling though. So, there's this... let's
call it a lingering smell, still hanging about. Hope it is unjustified.

In another thread you said:

That would mean you have two Prii?

The current accelerator assembly is mounted high up, on the fire wall, IIRC.
The pedal arm itself then hangs downward with an airspace -- an inch or
more -- between it and the floor. If the floor mats were to slip forward,
they'd go under the pedal. If they did go far enough forward to contact the
pedal where it is connected to the base -- something like 4-5 inches of creep
-- if anything, it would push the pedal towards the idle position.

So the mats wouldn't seem to be the cause of your "sticking," that is unless
your mats are really thick, like an inch or more.

It's a mystery to me.

More technically savvy members will no doubt post soon. As a '08 driver,
I'll be watching closely to see how this turns out.

 

I have no idea if this report is real or not.

Bob Wilson

 

Yes I have two Prii that I use. the 2004 is my mothers prius and the 2008 is my own. I bought mine because I liked my mothers so much. Except for this issue I have been really happy with the car.

 

OK, it's good to get that irksome detail out of the way.

The accelerator pedal assembly on the '08 uses two Hall Effect sensors --
very reliable devices, and in the Prius, fully encased --to generate dual
signals. The signals allow the CPU(s) to know not only where the pedal is in
its range of motion, but also the direction and rate of change of its position.

I suspect that the data stream is both dense and constant, allowing for
constant verification and error checking. As I understand it, the CPU induced
failure mode is to shut the ICE down, not speed it up.

So, something appears to be wrong.

It looks like folks need more info to work with. It's time to rack your brains;
What possible special conditions existed when the accelerator got stuck?

And by the way, have you removed those heavy mats, to be safe... just in
case they are the problem?

 

Cars with defective accelerators and brakes are tagged in production for sale only to that class of drivers.

 

Before I posted this issue to the forum I had taken it to the Toyota attached to this post you can see what they are saying. It seems that there were no codes stored. Also in answer to what kind of shoes I was wearing and the temperature. I was wearing the same shoes that I always wear and the weather was kind of cool but not freezing. I don't think that the problem is related to anything that I am doing wrong or the way that I am driving it. I just want the issue resolved before I am involved in an accident due to this issue. I know that the first post on this issue was posted by someone who hasn't posted to this forum before or since then but this is a real issue for me.

Thanks for reading this.
John Shaffer

 

Remember that the brake pedal has precedence over the accelerator. If for any reason you get uncommanded acceleration, mash on the brake pedal and keep your foot there. Once you have the car under control, pressing and holding the power button should force a shutdown.

Obviously you shouldn't need to take drastic measures, but it's good to plan the procedure ahead of time just in case. I won't say I suspect driver error, floor mats, or some other mundane issue, but I will say I suspect the problem was a fluke and you won't see it again. Keep your emergency plan in mind, keep driving, and let us know if you get any more data points.

Tom

 

This sheet pretty well matches the earlier report from the NHTSA and Toyota about all weather floor mats on the driver side. Without seeing an NHW20 accelerator assembly taken apart, it is difficult to come up with another, plausible, hypothesis.

My recommendation is to take out the driver side floor mat and clean the carpet at the car wash. You seem to have figured out how to control it so you should be fairly safe.

Bob Wilson

 

If possible, please give an exact description of what happened.