Another Prius problem

[CNG MOTORS]

And all these years of flack I got for my avitar :0)

http://news.yahoo.com/s/ap/us_runaway_prius

[siai47]

Re: Another Prius problem

Toyota may be having problems---lot's of them. But does anybody remember the Audi "unintended acceleration" problem a few years back? Millions were spent trying to find out what the problem was and after news reports started surfacing everyone's Audi just start driving away by itself like it was possessed by Demons. Does anybody remember what the final problem turned out to be? (hint--it wasn't the car). A lot of what's going on here isn't the car either but with the media and legal frenzy going on who can resist using the car as a scapegoat for your inability to drive. A stuck accelerator can startle you but it shouldn't kill you. I had it happen a long time ago in a old Chevrolet when the engine mount failed causing the left side of the engine to lift up jamming the accelerator (this was a common problem that led to a large GM recall at the time). In any event, any number of things can stop the car---turn off the ignition, put the transmission in neutral, firmly apply the brakes to bring the car to a stop. By firmly applying the brakes the car will stop---the brakes will overpower the engine on any car. The idiots that are claiming on the news that their car was still accelerating with the transmission in neutral or reverse, the ignition shut off, or with "both feet on the brakes" either did none of the above or were in such a panic that they didn't know what was happening. At least they had the presence of mind to find and then dial 911 on their cell phone to ask for assistance while their car is completely out of control. Sounds a lot like the old Audi problem. Remember, in the end, we all pay for this as a nation with higher product costs. I hope the class action attorneys can all order larger yachts with the money they make off this to help jump start the economy.

[CNG MOTORS]

Re: Another Prius problem

I dont dis-agree there are a lot of morons out there driving. It's big news now so every incident will be covered, more so than before. There was a 911 call from a runaway lexus I listened to with a stuck accellerator that entered a intersection, all four in the vehicle died and 911 recorded it all, I don't think they were faking.

[siai47]

Re: Another Prius problem

I think the bigger issue is that cars are so reliable that people just aren't trained on how to react when something goes very wrong. I sure people with the old Audi's weren't "faking" anything either, its just that the news reports the details of the accidents that result but don't tell people what do do in case of an emergency. I have yet to see any demonstration on any newscast of what a car with a stuck accelerator feels and sounds like and what various things you can do to correct the problem---before you end up on the 5:00 news. Everyone, regardless of what they drive, should be informed as to what to do.

[CNG MOTORS]

Re: Another Prius problem

I've already discussed with my daughter and wife what to do if this were to happen in their vehicles. I only thought to do this because of the prius reports. I've instructed them both to turn off the ignition. It's not a diesel so it should shut down the their cars. I told them if that didn't work to put it in nutral and let the engine blow. Most modern cars have safeties in them that don't let you go into P or R while the car is moving foward.

[Larryect]

Re: Another Prius problem

I can't believe so many people don't have a clue what they can do when something goes wrong.

I had a talk with my wife and all the kids. I told them to put it in neutral. As far as I know, there is still linkage from the shifter to the transmissions. Although, I know there is some computer control as well. The "won't that ruin the engine" question came up. And I said "So what?", it would be better then dying in a crash, and may be covered by insurance. But, if the computer is not locked up, it should not let the engine over-rev.

Turning off the engine would be another chioce. But, if you are not careful and go too far, you could lock your steering wheel. You will loose power brake and sterring assist. Also, I guess with some of the new cars, to shut off the engine is another computer input. You have to hold the button down for several seconds. Again, if the computer is ignoring you it may not work.

Bottom line, there are several options to at least try.

Be safe.

[advocate]

Re: Another Prius problem

I can't believe that you don't understand how a Prius (or just about any modern automobile works).

THERE IS NO LINKAGE BETWEEN THE SHIFTER AND THE TRANSMISSION. I REPEAT: THERE IS NO LINKEAGE BETWEEN THE SHIFTER AND THE TRANSMISSION!

The shifter is just an electric switch. It's connected to the ECU ("Engine Control Unit" or "Engine Computer") through the CAN-BUS, just like everything else. The ECU controls the engine speed and the transmission. It does so based upon numerous inputs, including the throttle position sensor (an electric sensor on the accelerator pedal, which is ALSO NOT connected to anything other than the ECU), and various emissions control sensors.

If the ECU is working properly, then when you move the shifter to nuetral, the ECU will instruct the transmission to go into neutral. If the ECU freezes up while you're accelerating and won't respond to any input, then it may not respond when you move the shifter switch to neutral.

The on/off switch is also just another switch that's connected to the ECU. When you push it, you are asking the ECU for permission to shut off your car. It's very similar to clicking "Start," "Shut Down" on your Windows PC. Toyota has it set up so that when you're not moving, it will turn off the car instantly. When you are moving, the car will turn off if you hold it for 3 seconds.

Again, if the ECU is working right, then it should the engine off when you ask it to. However, if the ECU freezes up, then it may not respond to a request to turn the car off. It may just sit there accelerating the engine until you hit something.

To complicate matters even further, the Prius uses the engine for a significant amount of its braking. That's how the regenerative braking feature works. You hit the brakes, and the car puts the electric motor into reverse mode, so it acts as an electric generator. If you hit the brakes hard enough, or you get to a relatively low speed, then the braking control computer decides to hit the real brakes. So, if your engine is accelerating out of control, a significant portion of your braking (the regenerative part) is completely gone. You have only the smaller non-electronic braking system.

In a more conventional car, the problem is even more pronounced for another reason: When you go to Wide Open Throttle (WOT), the system diverts all vacuum pressure to the engine. That vacuum presure is normally used for the power assisted brakes to work. But when you go to WOT, the vacuum pressure is diverted and the power braking system won't work. When that happens, you can still operate the brakes, but you have to put at least a seventy-five pounds of force on them to work. If you just push the brakes like you normally do, you'll hit an end point. If you don't know better, you'd think that end point is the floor. That's actually the spot where you have to stand on the brakes to get any braking power. If you've ever driven a car that doesn't have power assisted brakes, you'd understand why in the 1950s, men were traditionally the drivers in the family.

Even when you go to WOT, You do have some left over vacuum pressure, usually for 1-2 pedal presses. If you ever encounter a sudden acceleration situation, DON'T WASTE THEM.

And so the moral of this story is that if you encounter a situation where your car accelerates out of control, shift into neutral and hit the brakes ONCE. HOLD YOUR FOOT FIRMLY ON THE PEDAL AND DO NOT LET UP. Try to stop against something. If you think you don't have any brakes and the your foot is going to "the floor," then stand on the brake pedal.

I want to add that I'm not saying that Toyotas or any other vehicle are less safe because they are electronic. Mechanical vehicles in the 1980s had sudden acceleration problems, and a mechanical throttle can also stick, because the throttle cable or a portion of it becomes stuck or because a return spring brakes. I actually think that newer electronic vehicles are much safer than older mechanical vehicles. The one caveat is that electronic problems can happen in a instant, without warning, even in a newer car. Mechanical problems in mechanical throttles tend to develop gradually, are usually easily noticed before they become a problem, and tend to happen in cars that are many years old.

[larrycng]

Re: Another Prius problem

Well said advocate! An excellent explaination of how the system works especially on vacuum (power) break system

Might I suggest that those of you who have friends who drive the Prius give them a copy of Advocate's comments in order to understand how the system works to provide suggestions on how to deal the situation.

On the lighter side. you always put a big ugly toggle switch with a big red safety cover on the dash that would cut the power to the vehicle's computers ( in effect un plug the computer)

Larrycng

[larrycng]

Re: Another Prius problem

Well said advocate! An excellent explaination of how the system works especially on vacuum (power) break system

Might I suggest that those of you who have friends who drive the Prius give them a copy of Advocate's comments in order that they understand how the system works to provide suggestions on how to deal the situation.

On the lighter side, you always connect the computer power leads through a big ugly toggle switch with a big red safety cover and put on the dash. The switch would be used to cut the power to the vehicle's computersin an emergency. (it would in effect un plug the computer)

Larrycng

[malibu]

Re: Another Prius problem

SO, If the Vehicle BUS hanges or the ECU goes out all is lost? Do vehicles have any redundancy like airplanes? Embedded controlles do not last forever. As vehicles get older are they all going to eventually fail?

[siai47]

Re: Another Prius problem

Let's try to get over this. Of course there are redundant systems on a car---even a Prius. The brakes are basically mechanical/hydraulic with power assist/regeneration. The steering system is mechanical with electric assist. If space aliens cut all the electric power on the planet, you could still steer the Prius to the curb and bring it to a stop. However with the power out throughout the planet, the media couldn't start spreading fear and blame for the problem--real or imagined. Its those large aircraft in flight with all the redundant electrical systems that would be in big trouble as many of the "fly by wire" systems do not have a mechanical connection from the flight controls to the control surfaces. Bottom line is the kind of thinking coming out of the media, government officials and lawyers will lead to the end of technological progress while they line their collective pockets with money from whatever problems exist in a product. Changing technology brings problems that may or may not have existed with mature technologies. I am sure Toyota sat around in engineering sessions trying to figure out how to put the minimum equipment and design in thier vehicles so they would eventually ruin their reputation and kill their customers. It is this same thinking that requires me to buy a gasoline fueled car. Everyone knows cars have always run on gasoline, anything else is unsafe. You will get electrocuted in a car powered by electricity. A car powered by natural gas will explode and kill everything in a mile radius in any minor accident. Hydrogen? Remember the Hindenburg---are you nuts! END OF RANT-- I AM GOING BACK TO MY CAVE !

[advocate]

Re: Another Prius problem

Vehicles do have some redundancy. For example, there are two throttle control sensors on the accelerator. One operates at 7.5 volts and the other at 2.5 volts (or so I've read) and the ECU must read both of them in order to accelerate the pedal. So, if one TPS fails, the vehicle will enter into a failsafe mode and basically stay at idle. As far as I know, there's only one ECU.

Honestly, I think it was a terrible mistake to have the ECU control the transmission. But, Toyota's official position is that it makes its ECU's so well that they almost never fail, and that when they do fail, they just die completely so that the car won't work at all.

Regarding the steering lock, on my Avalon (which uses the push button system), the steering lock doesn't engage until you open a door. Thus, turning off the car off using a push-button system probably won't engage the steering lock. I don't know what happens to the transmission, i.e. does it go into neutral or does it stay engaged and keep spinning the engine, and I'm not keen to try it either... So I don't know what happens with the power brakes.

[advocate]

Re: Another Prius problem

The claims in the below posting are absurd. The very reason that vehicles are safer today is that lawyers and safety advocates have been constantly pushing for safer vehicles. The reason we have seat belts, air bags, crumple zones, emergency brakes, etc. are because of congressional mandates and lawsuits. The auto industry resisted seatbelts for years before the government finally mandated them. The same was true of airbags.

The actions that come out of today's media hysteria will undoubtedly make vehicles safer. We'll likely see more redundancy (which is good) and manual ignition kills switches (similar to the emergency brakes on cars today).

Again, I have no doubt that electronic systems are safer than mechanical systems. I also agree that the current media hysteria is just that: Hysterical. However, it's that kind of hysteria that actually gets thing done in this country. The auto manufacturers are not going to go back to manual controls for two reasons: They are more expensive and less safe. However, there's no reason why automobile safety cannot continue to improve, and today's media hysteria will be responsible for tomorrow's safety improvements.

You make an excellent point about airplanes. Airplanes are INCREDIBLY safe precisely because their manufacture and repair is heavily regulated, and the litigation risk for a crash is huge. When they crash, there is ALWAYS media frenzy, because the very notion (and pictures) are often spectacular. You've proven that media frenzy, government regulation, and lawsuits make us safer. Thank you!

Let's try to get over this. Of course there are redundant systems on a car---even a Prius. The brakes are basically mechanical/hydraulic with power assist/regeneration. The steering system is mechanical with electric assist. If space aliens cut all the electric power on the planet, you could still steer the Prius to the curb and bring it to a stop. However with the power out throughout the planet, the media couldn't start spreading fear and blame for the problem--real or imagined. Its those large aircraft in flight with all the redundant electrical systems that would be in big trouble as many of the "fly by wire" systems do not have a mechanical connection from the flight controls to the control surfaces. Bottom line is the kind of thinking coming out of the media, government officials and lawyers will lead to the end of technological progress while they line their collective pockets with money from whatever problems exist in a product. Changing technology brings problems that may or may not have existed with mature technologies. I am sure Toyota sat around in engineering sessions trying to figure out how to put the minimum equipment and design in thier vehicles so they would eventually ruin their reputation and kill their customers. It is this same thinking that requires me to buy a gasoline fueled car. Everyone knows cars have always run on gasoline, anything else is unsafe. You will get electrocuted in a car powered by electricity. A car powered by natural gas will explode and kill everything in a mile radius in any minor accident. Hydrogen? Remember the Hindenburg---are you nuts! END OF RANT-- I AM GOING BACK TO MY CAVE !

[siai47]

Re: Another Prius problem

All done posting here---it's been nice ride--didn't know I was on a legal fourm.

[CNGvw]

Re: Another Prius problem

siai47 it's there way or the hi-way 95% of them have never build any thing but bull ###. bla bla bla.
If it is CNG and did not come from a dealer it junk/ not legal/not right bla bla bla.
It's like they say if you make dog food feed them dog food because they will not know any better.