Toyota recall hearings

[garbon]

I still hope Prius owners burst into flame.

[grumbler]

Nothing like name-calling to gain a higher ground. 

Name-calling?  Nonsense.  Tweaking a user name is nothing on languish.

Nevertheless, I'm actually fairly confident that I do know more about how cars work than a typical CHP officer, or the majority of people for that matter.  For one, I was part of a group that built a racecar in college in the SAE club, so that required some intimate knowledge about the working of cars.

Unconvincing.  Being "part of a group" conveys no special knowledge, and using "the majority of people" as a group even more knowledgeable about cars than the CHP just damages your case further.

As for the CHP officer who got killed, he did do several things wrong, and that's not in dispute.  He did try to shut off the car, but he did not know how to, as he was driving an unfamiliar loaner.  Partly the fault of Toyota for making unintuitive controls, but also partly the fault of the driver for not being familiar with them. 

The car would not shut off (which surprised me when I found out).  I have never heard that there was an alternate method for shutting down the car that he (and the others who suffered this failure and survived) didn't know about.  Link?

He also wasted a golden opportunity to slow the car down.  He did manage to keep the car under control for some time, but he failed to use the brakes fully to stop the car, and he rode them instead.  Unfortunately for him, that boiled the brake fluid and killed the brakes eventually, and now he was SOL.  All the mistakes are understandable, but not something that an educated driver would make, unless he lost his mind (which is also understandable).

He tried to use the brakes to fully stop the car, and failed.  The engine was just too powerful.  He was running out of highway when he, in desperation, rode the brakes to the breaking point.  Having left over brake fluid with him in his funeral pyre would have availed him naught.  His mistake, of course, was either (1) not pulling the floor mat back, or (2) getting into a vehicle who electronic control systems were subject to periodic failure. It is not 100% sure that (1) is true.

[KRonn]

I just heard that Toyota will start putting ejection seats fitted with fast opening parachutes, so that drivers and passengers can have a decent chance of escaping these run away missile cars.   

[Berkut]

I just *knew* that it DG would turn out to be a casual expert in automobile operation. He is an expert in almost very single field there is, I think.

[Darth Wagtaros]

Is the grumbler/DG spat over?  The UST is getting thick.

[DGuller]

Unconvincing.  Being "part of a group" conveys no special knowledge, and using "the majority of people" as a group even more knowledgeable about cars than the CHP just damages your case further.

I have no intention of proving my resume to you.  Suffice to say, I'm sure that majority of people did not diagram and screw on and off various parts such as steering rack, suspension arms, tie rods, wheel assemblies, brake lines, pedal assemblies, steering columns, steering wheels, and tires.  I didn't weld the car frame, mount the engine, or otherwise work on the rear of the car besides some suspension bits, so you got me there.

As for me claiming that majority of people are more knowledgable than CHP, that was just sloppy wording on my part.  I did not mean to imply that CHP is less knowledgable about cars than general public.

The car would not shut off (which surprised me when I found out).  I have never heard that there was an alternate method for shutting down the car that he (and the others who suffered this failure and survived) didn't know about.  Link?

The particular Lexus that the CHP guy drove could shut off if you held the off button pressed for three seconds.  He didn't hold it when he pressed it, and erroneously thought the button didn't work.  I don't have any links, I read about it a long while ago.

He tried to use the brakes to fully stop the car, and failed.  The engine was just too powerful.  He was running out of highway when he, in desperation, rode the brakes to the breaking point. 

First of all, the engine is not more powerful than the brakes, that's just nonsense.  Anyone with some knowledge of physics can come to this conclusion pretty quickly.  How long does it take for a car to go from 0 to 60?  About 6 seconds for a moderately expensive non-sports car.  How long does it take to brake from 60 to 0?  A lot less than 6 seconds, I hope.  Unless the car's mechanical and aerodynamic drag is impossibly bad, that implies that the brakes are more powerful than the engine.

The problem with the brakes is that the normal car brakes are not designed for heavy duty.  They'll work for some time, but not for long if you're working against the engine, or having a couple of heavy braking episodes in short succession.  Pretty soon the brake fluid overheats, and no longer acts like an incompressible fluid, which is not a good thing in hydraulic systems. 

That's why if you have to use the brake to stop the car with stuck throttle, you have to do it at first shot and not stop doing it until you're stopped, or go slow enough to just nudge the car into the steel barrier.  The instinct is to at first ride the brakes to keep the car from accelerating, rather than just jamming them with both legs to stop the car no matter what and where.  That wastes the one shot you have at bringing the car to a stop, and once the brakes fluid goes, so does your car.

[garbon]

I just *knew* that it DG would turn out to be a casual expert in automobile operation. He is an expert in almost very single field there is, I think.

Are Dgul and Carrot the same person?

[DGuller]

I just *knew* that it DG would turn out to be a casual expert in automobile operation. He is an expert in almost very single field there is, I think.

You got good instincts then, because I do in fact know a lot about how cars operate for a non-automotive engineer, especially from the mechanical perspective.

[DGuller]

I just *knew* that it DG would turn out to be a casual expert in automobile operation. He is an expert in almost very single field there is, I think.

BTW, just curious, in what other fields did I claim to be an expert?

[JacobL]

Toyota
struggling
hmmm

[dps]

Being "part of a group" conveys no special knowledge, and using "the majority of people" as a group even more knowledgeable about cars than the CHP just damages your case further.

In my experience, the typical police officer, though they spend much of their time in a patrol car, have no more idea how cars work than any other motorist.  The CHP may have a higher standard of driver education and knowledge for their officers than most police forces;  I somewhat suspect that they do, but I haven't checked.

[MadImmortalMan]

Toyota Fires Back: Electronics Don't Rewire Themselves
After a college professor modified a Toyota Avalon to suddenly accelerate without pressing the gas pedal, Toyota held a briefing to explain what most media outlets don't get: Electronics don't rewire themselves.
By Mike Allen
Published on: March 8, 2010

I wrote here last week how improbable it was that electromagnetic interference (EMI) could fool the Hall-effect sensors that were the subject of the massive recall of 2.4 million late-model Toyota and Lexus vehicles. Specifically, I talked about how the sensors were redundant and isolated, and how it was extremely unlikely that random radio waves could induce spurious signals that trick the engine computer into commanding the engine to go full throttle.

Then professor of automotive technology Dave Gilbert, of Southern Illinois University's auto technology department, went ahead and modified a new Avalon to go to full throttle with the flip of a switch, by altering the same circuits I wrote about. Gilbert appeared on ABC news and testified before Congress that his manipulations demonstrate how easy it is for Toyotas to accelerate out of control. And there's more: He suggested that his analysis shows how all electronic throttles are inherently dangerous, because Toyota's throttle-pedal electronic architecture is similar to that used by almost every car manufacturer.

Whew. I must say the video footage that ABC aired is compelling. Gilbert demonstrates how a seemingly simple short in the throttle pedals' circuitry can make the car go to wide-open throttle (WOT) at whim. Hide the women and children.

Except he's wrong.

Let's get specific: The Toyota throttles (as well as a lot of others) use two Hall-effect sensors, which operate between 0 and 5 volts DC. The voltage increases by 2 to 2.5 volts between the pedal position representing idle and the position for WOT. There are two discrete sensors on separate circuits. The second circuit runs about 2 volts higher than the first. Both sensors have independent 5-volt supplies and independent 0-volt reference returns (meaning they don't share a ground), and they aren't grounded to the chassis. The engine control module (ECM) calibrates the sensors' idle position at every engine start. And if the two sensors don't agree fairly closely as to the percentage of engine throttle called for, the ECM goes into a low-power, limp-home mode, sets a trouble code, and turns on the "Check Engine" light. This means that a sticky pedal may cause the engine to return slowly to idle or not at all. This also means that a using a cell phone or driving under a power line isn't very likely to make you crash and burn.

Here's what Gilbert had to do to make his Avalon go rogue: He had to cut open three of the six wires that travel from the pedal assembly to the engine computer. Two of the wires send the accelerator-position signals—one for each Hall-effect sensor—and one is a 5-volt power supply. Next he had to insert a specific 200-ohm resistor between the two signal wires. Finally, he had to generate a direct short between the 5-volt supply lines and the signal leads. The new wiring essentially mimicked a size-12 mashing of the pedal to the carpet and the engine went to WOT. Also, the order of the modification is important. Apply the 5-volt power lead to the wires before inserting the resistor and the computer would instead throw a fault code and go into limp mode.

Gilbert has managed to prove that he can game the system. Let's examine what would have to happen for such a fault to occur in a real-world situation: Say that, maybe, water is getting into the pedal assembly, or the pedal's wire loom connector is shorting stuff out. First off, the only moving part in the pedal is the part you step on, which has a magnet mounted to the far end. The magnet sweeps inbetween a pair of Hall-effect sensors, which are potted in epoxy to keep them dry and safe. The wiring connector on the pedal has an 0-ring seal to keep out moisture. The individual wires that go into the mating end of the connector have individual seals on them that do the same, and the whole business has a mechanical latch to keep it nice and tight.

There's more. The two signal wires aren't adjacent inside the connector; they're separated by two other wires, one signal ground and one supply wire. So our theoretical 200-ohm, corrosion-induced electrical path would have to bypass two other conductors. That's another big hurdle. Typically, when you find corrosion inside wiring like this, the resistances are closer to 2000 or 2 million ohms, not as small a resistance as 200 ohms. And the resistance value is very specific: A 10 percent difference up or down would put the two sensors out of the acceptable voltage range and wouldn't call up WOT. Even if heavy corrosion were to bridge the connector, how likely is it to be exactly the resistance that's needed?

The next thing in the sequence is a dead short from either of the signal lines to a 5-volt power line. Again, the resistance path usually seen as a result of corrosion is customarily thousands of ohms or more, not the very low resistance needed to energize the signal lines. And, yes, it has to happen in that order. Shorting the power line to the signal line has to happen last.

One pertinent factoid: Not a single case of sudden unintended acceleration (SUA) has been attributed to bad wiring. None. Toyota has been harvesting parts from vehicles with documented SUA issues as part of the recall, and they're checking them all. None of them have shown any sign of corrosion or shorted wiring. Toyota also illustrated that Gilbert's modification works on cars from many different manufacturers. During a webcast explaining the modifications, Toyota had a half-dozen cars built by a half-dozen companies that were rewired in the same manner. All of them produced the same result as that Avalon. The question is: What would make an engineering professor stick his neck out so far?

We can't answer that, but we do know that Gilbert was paid $1800 for his engineering study by Sean Kane, a safety consultant. Kane's for-profit firm Safety Research & Strategies Inc. works with lawyers who are currently suing Toyota over the sudden acceleration issue. He blames Toyota for making the fail-safes and redundancies in the accelerator system too easy to circumvent, arguing that Toyota should have engineered the system to be more robust.

My take on it is this: You can engineer around any safety system if you try hard enough. I had a car come to my repair shop years ago with the throttle stuck open partway. The cause was easy to find—the driver had used a coat hanger to hold the carburetor throttle blades partway open, because the throttle cable had snapped and he had no way to drive the vehicle with the engine at idle. Sort of the same thing as Gilbert's demonstration.

[grumbler]

In my experience, the typical police officer, though they spend much of their time in a patrol car, have no more idea how cars work than any other motorist.  The CHP may have a higher standard of driver education and knowledge for their officers than most police forces;  I somewhat suspect that they do, but I haven't checked.

In my experience, operating vehicles at high speeds, and dealing with other vehicles operating at high speeds, is part of the curriculum for highway patrolmen.  May be different where you are, but i would need evidence that turning off the engine or dropping out of gear is entirely neglected as a means of slowing a vehicle to believe that a highway patrolman faced with a situation like this would not think of them.  That is, of course, DGullible's claim (and yours, if you are supporting him).

I would argue common sense, in fact, if I didn't know Languish better than that.

[dps]

In my experience, the typical police officer, though they spend much of their time in a patrol car, have no more idea how cars work than any other motorist.  The CHP may have a higher standard of driver education and knowledge for their officers than most police forces;  I somewhat suspect that they do, but I haven't checked.

In my experience, operating vehicles at high speeds, and dealing with other vehicles operating at high speeds, is part of the curriculum for highway patrolmen.  May be different where you are, but i would need evidence that turning off the engine or dropping out of gear is entirely neglected as a means of slowing a vehicle to believe that a highway patrolman faced with a situation like this would not think of them.  That is, of course, DGullible's claim (and yours, if you are supporting him).

I would argue common sense, in fact, if I didn't know Languish better than that.

I have no experience with the curriculum of highway patrolmen;  exactly what experience with it do you have?  Besides, knowing how to operate a device and actually knowing how it works are different things--for example, almost everyone knows how to operate a TV, but many people have no real idea how TVs work.  On the other hand, I fail to see that any special training is needed to come up with the idea of trying to stop a runaway car by turning off the ignition or dropping it out of gear. 

I'm certainly not supporting DGuller;  I find his claims to expertise in automotive matters to be laughable, but I don't think that cops automatically have any special expertise in the matter either.  And I did state that I suspect that the CHP may give its officers more training on the subject than the normal police force.

[DGuller]

I'm certainly not supporting DGuller;  I find his claims to expertise in automotive matters to be laughable,

Really?  What do you find laughable about them?  So far in this thread I've been the only one who displayed the knowledge of how brakes on a car actually work, and how they can stop working.  Care to back up your dismissive attitude, or will everybody in this thread just not bother with the facts?