2004 Toyota Prius: Three Ways to Deal With a Stuck Throttle

So a normally functioning Prius, with normally functioning electronics, said electronics will prevent brake and throttle overlap, will allow the car to be shifted into neutral, and will prevent reverse from being engaged. That makes perfectly good sense.

Now what if the electronics are not functioning normally?

So that guy is full of BS

The California guy is a crook. As much as it pains me to post a link to Fox News, here it is

http://www.foxnews.com/story/0,2933,589090,00.html

I'm no fan of Toyota. Never have been, never and never will be but all this Toyota acceleration/no brakes fear-fad is nothing less than horsesh*t and i guarantee history will look at it as such.
Yes, winter mats on TOP of a summer mat *could* jam the gas pedal. TAKE IT OUT. The "second recall" was because in extremely rare cases a SLIGHT resistance in the gas pedal returning to position, SLIGHT. All the rest of this is fear mongering, me-sue-too!, and outright lies. "Didn't want to flip the car"? What an ass, he wanted to be famous.

@prndlol,

Agreed 1000% with you. Every sue-happy sewer trial lawyer is smacking their lips right now.

That California guy is looking out for some lawsuit money & was out to commit insurance fraud. He was 700k in debt, failed in business & 5 months behind on his car payments.

Yeah, sure, it accelerated on it's own.

And look for every octogenarian who crashes a Toyota because they confuse the gas pedal & brake pedal to blame Toyota.

Sometimes I wonder why IQ tests aren't mandated before granting Drivers Licenses.

fun test!

toyota may have problems (I believe they lied about floor mats and such) but the pendulum has swung the other way, and hysteria rules.

Way#4: Don't drive. You are too stupid to behind the wheel anyway.

I will ask again the question no one wants to answer:

Now what if the electronics are not functioning normally?

And also, what do we assume then, the CHP officer in the Lexus ES was involved in a homicide/suicide just to discredit Toyota? Or that he pushed on the wrong pedal without thinking differently long enough for someone in the car to call 911? I simply don't understand the obsession with insisting nothing ever could or ever will go wrong with a Toyota. Why is the automotive community so devoted to defending the honor of the most dull manufacturer out there, while magnifying and trumpeting every little fault in a GM, Ford, and Chrysler?

I think a better test is to be nasty.

1. Spill soda everywhere to make everything sticky, shifter, gas pedal, brake pedal, engine, throttle body.
2. Abuse everything, kick the accelerator, brake pedal, shifter, etc. Open up the plastic covers if needed and stab stuff with a screwdriver.
3. Put everything back together and see if it drives
4. Fix whatever is needed to make it drive but still be nasty
5. Racetrack + autocross for 24 hours straight.

If there was any electronic problem, the system "should" throw a DTC and go into limp mode.

@stovt001: It's pretty much accepted by everyone INCLUDING Toyota that the winter mat placed on top of the summer mat in that Lexus jammed the pedal. Go research it.

that guy who said he had a stuck throttle and couldn't stop it is full of s**t. I didn't buy it when i heard the reports, and this just kind of confirms my theory of the guy from cali in the news being full of crap.

stovt001: "Now what if the electronics are not functioning normally?"

Don't feel too bad. In the other thread IL started on this, no one wants to explain how the State Trooper saw the Prius driver braking (brake lights if not more), yet the car's throttle override didn't seem to kick in.

I will not be surprised if this guy is a fraud, but people have put on blinders in trying to prove it.

Edmunds, can you see if you can burn up the Prius brakes by applying light braking and full throttle?

I really want to know why the brake lights were on (so says the state trooper). So something must have been wrong electronically, not mechanically. I would also like to see if you can smoke the brakes. Does any one know what Toyota said about his Prius? I know they investigated it.

stovt001:

I don't think people are taking toyota's side as much as there seem to be alot of these reports that are coming up as frauds. There has to be a reason sooo many more reports came up after january.

I don't trust toyota in this and I also don't trust most people. People are greedy and lying for the same reasons toyota did

This is just a big mess

I believe that Dan touched on this in the article.

"Brake test: Turns out there's a brake override feature in a Prius. As soon as I press on the brakes with anything more than casual effort, the wide-open engine and electric motors stop propelling the car forward and the brakes take over."

My understand of this would be that you could press the brakes just enough to turn on the lights and have the brakes applied without activating the override which after long enough would overheat the brakes. Thats just my thoughts on it though...

Hmmm. Maybe you could, since Toyota's new system is programmed to allow drivers who ride the brakes with their left foot. So I say it's time to get to the track and try it out. Also, it's time to issue a plea to the public for anyone who was on the highway to call and say what they saw.

Some more info on this fraud jim sikes

http://jalopnik.com/5492199/exclusive-ex+business-partner-claims-runaway-prius-driver-a-scammer

Wouldn't the ABS prevent the brakes from overheat at least for awhile?

mzbamf, how do we know William Sweet isn't a glory hound? All we have is hearsay. If this really happened, there should be court documents, but the reporters at Jalopnik are too lazy to dig them up.

Again, I'm not defending James Sikes. It's just that tossing around hearsay is useless. My biggest gripe in your example is the lazy reporting.

Come on Dan, I would have expected something a little more insightful from you here on Edmunds! This article does not give us car readers any new information that we didn't know already. I love how people keep writing these articles and post videos on "how to stop your perfectly functioning runaway Toyota". I guess all these drivers crashing are just morons then, faking problems crashing their brand new cars to try to win a lawsuit with Toyota. I admit that there probably are a few out there though.

Let's be honest, most people out there on our roads have enough trouble not crashing into the person in front of them, not flying off the road and hitting something, not running red lights, not cutting off cars in their blind spots, the list goes on and on. Keeping that in mind no wonder people freak out and do not think about how to control their out of control car right away. The bottom line is we have a serious circuit/memory problem with throttle control being avoided here, and U.S. driver skills are seriously lacking.

Lets say there's a hypothetical electical issue. Maybe the throttle position sensor so the throttle no longer works properly. Well, I would think the braking system would still work and the override function would still work. Okay, so lets pretend the override function no longer works. Fine, shift the transmission into neutral. Okay, lets pretend the throttle system, brakes, and transmission selector don't work. Well, they all operate as in integrated system together to maximize efficiency, so lets say they all fail. Well, lets shut the car off. The Prius isn't exactly a super heavy car; as long as you don't have to make a 90 degree turn, you don't need power steering. Oh yeah, my parents Lexus RX400h hybrid still has the mechanicl parking/emergency brake. I would assume the Prius does too.

A couple of things that are left out of this test, that no one has addressed. One, if the brakes are already hot, would not brake fade be a factor, and the fact that Dot 3 brake fluid boils at 284 degrees. If the calipers get hot enough, the heat transfer could cause the brake fluid to boil, and everyone knows that air is not compressible, thus a loss of braking. The reason they do not use Dot 5 silicone brake fluid in anti-lock systems is that air bubbles form during anti-lock application. Also at full throttle, the vaccuum reserve is depleted, thus requiring higher pedal effort.

As for all the people that feel that the simple solution is to shift to neutral, brake and shut off the engine, one must take into account that most of the drivers that are having issues are getting up there in years. Driving a vehicle in which you have no control causes one to panic, for example, is there any driver that has not experienced their car hydroplaning? Is not hydroplaining a very scary experience, especially at high speed? I want everyone that thinks that its the drivers fault to think about that. How do you control a car that is skating on a layer of water?

I had a friend that had the throttle cable brake on his Suzuki RM 250 while approcahing a jump, and caused his bike to stick at wide open throttle. Hitting the brakes, switching off the kill switch still did not prevent him from landing in a tree!

Didn't want to FLIP the car??? Correct me if I'm wrong, but there are many different odors of B.S. with that excuse, beginning with :

A) Isn't this what a torque converter is for? Any excess torque from being in gear at high revs will be absorbed by the torque converter and it won't upset the car's balance.

B) It's A PRIUS. It could not have been traveling more than 100 miles an hour with the pedal floored, and all that excess torque that its giant engine generates is not not nearly enough to upset the car enough for it to flip considering he was on an open highway going in a straight line (presumably).

C) Did he try hitting the brakes? The guy is obviously just whoring for attention and trying to turn himself into a news story.

I hope the truth leaks out, though I don't count on it since most people have no idea what they're talking about and can be manipulated into believing almost anything.

kingfish4,

Your points are well-taken, but hydroplaning is different than acceleration. You have virtually no control in hydroplaning; brakes, steering, or otherwise.

In acceleration, you have control of those 2 things. Could it be scary? Of course. But it should not cause a tremendous panic. There are a myriad of solutions, such as use the e-brake, jam the actual brake, go into the neutral, or turn the engine off.

A Prius, and most Toyotas for that matter, don't accelerate quickly enough to not allow us time to react before the situations gets hairy. It's not a Lamborghini which would be doing well over 120 mph in a matter of seconds.

Just sayin'... Maybe it is difficult for me to see the perspective of an elderly, but at the same time I expect all drivers should have a basic idea of how a car works.

Mikeebear, assuming that all drivers in the US have basic knowledge on how a car works is a poor assumption! It really boils down to the absolute lack of any type of driver education and the ridiculous ease of getting a drivers license.

It isn't just a driver education problem, it is GENERAL EDUCATION and budget cuts ain't helping.

Shifting to neutral means less force applied to the tires. Lesser lateral force applied to an object below its center of gravity => lesser destabilizing force. This is middle school material. It doesn't take an engineering degree to figure this out.

Kingfish -

I agree with your point about hydroplaning: in an instantaneous decision, our instincts don't always make the right choice. For example, I once hydroplaned coming around a curve and as I was slipping into the next lane over (no other traffic) I slammed on the brakes instead of just letting my foot of the gas. The result was a car that pendulumed and slid off the road.

However, these highway cases are in a different ballgame. Hydroplaning is a split second decision. Putting a Prius into WOT at 65mph is not.....and it's max speed is about 94mph AFAIK.

This gives drivers time to evaluate their options. How can I get the car out of gear? neutral. Can I shift down into lower gears limiting the max speed? Maybe. What happens if I get on a shoulder and slam on the brakes? Could work. Etc Etc.

I routinely drive close to that max speed, and most drivers regularly experience 70+ mph. Even at 94mph, the speed itself should not be panic inducing. Things aren't getting that blurry.

To give another comparison: I had a tire blowout at 75mph. Front drivers side. However, I had about 5 seconds of warning as it lost air pressure to realize something bad was happening. Because of that warning, my brain could react and I slowed the car down and got over even whe it was fully blown out. If it had been sudden, I might have braked hard or swerved.

My point is: a few seconds is all the time you need to adjust and start using your head rather than any bad instincts.

...

If this post by Edmunds is correct, I don't think it applies to many Toyotas. Edmunds names a brake/throttle override as present in their Prius, but Toyota is installing that as part of their recall in many models. It would've prevented the highway deaths of the original famed CHP Lexus.

Nonetheless, no one has ever explained to me why that CHP Lexus which was at very high speeds for a very long time....why weren't they able to shift into neutral?

Hydroplaning is not really comparable because you lose almost all control of the vehicle. WOT in a Prius allows you to steer and brake at least while the thing gets up to "speed".

No one has explained the brake fade issue. For example, when I was a teenager, I was running my 69 Nova hard and was approaching a stop sign at 65mph. Because the brakes were hot, I experienced a severe case of brake fade. My Nova had a straignt 6 and three speed manual. I let off the gas and hit the brake, the car would not slow down, I downshifted to second, but still could not scrub off enough speed to avoid going through the intersection, even though I had "several seconds" of reaction time. Thankfully there were no cars, but I did blow past the stop sign. This car also had manual brakes so the depletion of vaccuum assist was not an issue. Why do you think that they still have emergency ramps on steep grades on interstate highways.

What's with the worry you could put it into reverse at speed?? Reverse is locked out at anything over walking speed. Cars I've driven that could not be put into reverse at anything over walking speed:

1967 Ford Falcon
1978 Dodge Custom 100 pickup
1980 Lincoln Continental Mark VI
1984 Honda Prelude
1985 Honda CRX
1987 Chevy Cavalier
1996 Honda Civic
2001 Acura MDX
2001 Acura 3.2 CL Type S
2004 Acura MDX
2004 Porsche Cayenne S

Not too sure about my mom's old 1964 Plymouth Valiant; but then, it did have push buttons on the dash for the gears.

A prius accelerating out of control?
being scared by the acceleration of a prius?
being scared of 90mph in SoCal?

This must be a joke.
I got to test drive a prius at the OC Auto Show, floored the thing from a standstill, and I was suprised at how little power it had. brakes worked really well though (3rd gen) but perhaps that was because I was so underwhelmed at the power.
Now if a car can't accelerate from a standstill/slight rolling start, no way it'll accelerate very fast at speed.

On 405 I regularly see people pushing 90+mph in the fast lane and the area south of LA towards San Diego is more speed friendly if anything.

Unless there was an electrical gremlin (which I'm not ruling out), I don't know of any cars that can consistently sustain 90+ miles an hour while standing on the brakes.

As for the electronic gremlins - does an electric motor have enough initial torque to overpower the brakes? Perhaps the electric engine was in full force? Just an idea.

Kingfish, no one is commenting on your questions about brake fade and your scary experience in your Nova because it's almost 40 years later and brake component design and manufacturing have evolved significantly even thought the components look the same.

First, regarding fluid boil, when fluid does boil in the caliper, the brake pedal sinks to the floor. There is nothing in the owner's or CHP's incident description that indicates that the brake pedal sank to the floor. Fluid boil in a modern brake caliper is pretty hard to accomplish? Why? Because you would have to have a massive amount of heat transfer through the friction puck, through the steel backing plate, through the stainless piston, to FINALLY reach the piston.

Second, brake PAD fade (which is probably the fade you are thinking about) is theoretically possible, but modern friction materials (even the cheap economy pads) rarely experience a complete loss of Mu (friction coefficient) under 600-700 degrees F. That means our lame Prius driver could have done somewhere in the neighborhood of at least 5-7 panic stops all the way down to 0mph before the pads would have reached that temperature.

Finally, yes, I work for a company that manufactures brake pads, rotors, calipers, master cylinders and hydraulics.

Correction:

Because you would have to have a massive amount of heat transfer through the friction puck, through the steel backing plate, through the stainless piston, to FINALLY reach the BRAKE FLUID.