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Unintended Acceleration - Find the Cause

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  • steverstever YooperlandPosts: 40,157
    Maybe floor mats will just get banned.

    "Mercedes-Benz is recalling all-season accessory floor mats sold in model year 2012 and 2013 ML-Class vehicles because they could cause the car's gas pedal to get stuck."

    Mercedes-Benz recalls floor mats from ML-Class (Detroit News)

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  • greg128greg128 Posts: 336
    just did a bit of math and found the ratio of complaints to NHTSA for Unintended Acceleration to the total number of that car's sales for the last seven years (2006-2012)

    The results for 4 cars..Sante Fe, Camry, Accord, and Malibu.

    # of complaints : total sales
    Sante Fe - 1 : 6,404
    Camry - 1 : 2,960
    Accord - 1 : 31,360
    Malibu - 1 : 60,640

    The complaint rate for the Sante Fe is 10x that of the Malibu and the Camry is 20x.
    There are plenty of reports coming in for Toyota even after their recall, and Hyundai isn't trending very well either
  • greg128greg128 Posts: 336
    If driver error was responsible for UA cases, then it would follow that older drivers would have a higher report rate. However I checked the complaint rate for a car that probably has one of the highest average age buyer - Ford Crown Vic, and a car that should have a relatively much lower age driver - Toyota Prius.

    #complaints : total sales
    Ford Crown Vic - 1 : 26,450
    Toyota Prius - 1 : 3,060

    These complaints are made mostlly only after an accident of some kind and most reported multiple instances before the accident where the accelerator pedal stuck or responded abnormally. I am sure these are only a small percentage of actual occurances of UA.

    I think it is safe to say that there are definitely instances of driver error where the accelerator is mistaken for the brake, but that does not explain the much higher rate in some makes, even when pedal positions and floor mat placement is taken into account. Luckily this is rare, but apparently real, and in all probabiltiy having something to do the the electronics and computer control.

    This happened to a couple in their 60's in Korea in a Hyundai Sonata:

    Sonata UA Video
  • steverstever YooperlandPosts: 40,157
    "The lawsuit claims that certain Toyota, Scion and Lexus vehicles equipped with electronic throttle control systems (ETCS) are defective and can experience unintended acceleration. As a result, the suit pursues claims for breach of warranties, unjust enrichment, and violations of various state consumer protection statutes. Toyota denies that it has violated any law, denies that it engaged in any and all wrongdoing, and denies that its ETCS is defective. The parties agreed to resolve these matters before these issues were decided by the Court. This settlement does not involve claims of personal injury or property damage."

    Toyota SUA settlement website

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  • plektoplekto Posts: 3,738
    And so no evidence is presented. Everything is under NDA agreements and swept under the rug. This surely doesn't seem to me to be the behavior of a company that's got nothing to hide.

    BTW, the most likely actual cause was not covered at all in the filing. It's not a bad sensor or bad code. It's nothing mechanical. It's simply that the computer froze up and got locked into doing the last thing it was doing. You didn't have acceleration so much as the throttle stayed exactly in the same position where it was before the computer froze up.

    This happens to PCs, industrial equipment, and even aerospace components. Sensors and microchips often get stuck in a "livelock" (endless loop of repeating code) scenario when they unexpectedly crash.
  • steverstever YooperlandPosts: 40,157
    You can always opt out and file your own suit.

    I'm still holding out for tin whiskers myself. :shades:

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  • srs_49srs_49 Posts: 1,394
    edited February 2013
    For the past year or so, there has been an examination of Toyota's ECU code by some independent third parties (or maybe they were parties to some of the pending lawsuits, not exactly sure here). This examination took place under a very strict Non Disclosure Agreement (NDA), with very stringent security and associated monitoring and logging arrangements in place so that it would be clear who accessed what. The computer system that provided this service was isolated from the rest of the world - no internet access, email services (except within the secured environment).

    While the the examination showed no smoking gun, there were many instances of poor programming practices - something that you would not expect to find in code as safety critical as controlling the throttle. From what I heard, the code was certainly not anywhere the robustness that you find on critical flight software for an airliner, for instance.

    I think that it was because of these findings that Toyota is caving in to the inevitable.

    None of this is general public knowledge, BTW.
  • plektoplekto Posts: 3,738
    edited February 2013
    BUT... the livelock scenario has absolutely nothing to do with the code.(bad coding aside, of course)

    Nobody ever has tested the thing for abuse. As in literally hit the thing with a stun gun or physical shock and crash(software/hardware, not THE car) the thing while the car is running. What happens?

    Think of is as closer to the power supply on your PC. how often has it crashed where doing the three second reset hasn't worked? I bet it has happened to you at least once in your lifetime where you had to unplug the computer from the wall and restart it manually. The biggest tip-off is the start button not working to turn off the car. I suspect that the start button is really a power supply switch and it simply froze up.

    I do know that if a car was having UA, unplugging the battery lead would kill the engine as it would physically disable the injectors and coil packs regardless of whatever the computer might be trying to tell it to do.

    Is this Toyota's fault, though? Likely not. Computers crash for all sorts of non-code related reasons and none of them are covered under any warranty or service plan that I know of. So why does this matter to me, then? Because I see the same idiot designs in multiple cars and UA isn't confined to just a few Toyotas, either. The vehicles have to be designed to be fail-safe when it comes to the computers freezing while the car is running.
  • srs_49srs_49 Posts: 1,394
    Computers crash for all sorts of non-code related reasons

    Maybe, but i bet the large majority of PC crashes/hangups/BSDs are cause by software problems. Improper garbage collection, errant pointers accessing memory it shouldn't, etc are probably at the root of most crashes.

    none of them are covered under any warranty or service plan that I know of

    The typical shrink-wrap disclosure you're probably thinking of I don't think applies here. Did your car come with a lengthy EUA (End User Agreement) that says that none of the software on the vehicle is guaranteed to do anything correctly, and that if it does something wrong that causes loss of property or life that the SW vendor is not responsible?
  • plektoplekto Posts: 3,738
    No, but hardware faults such as bad memory modules are simply covered under the basic warranty. That you lose your data, well, it's never covered.

    Toyota can't really be sued because of outside influences, corroded wiring harnesses, vibration and shock, and so on. At most, they would be forced to change their design, though, which would be a good thing. But there's no money in that, really, so the lawyers don't bother.

    ie - what this entire "challenge" was about was not about finding the overall cause (no proper fail-safe designs in any of the drive-by-wire systems), but finding a cause that could end up in Toyota being sued for damages.
  • houdini1houdini1 Kansas City areaPosts: 5,870
    edited October 2013
    In the first big case to come to trial, Toyota was found not liable in a 20 million dollar unintended acceleration lawsuit. Looks like the cause all along was poor drivers and greedy lawyers. At least that is what the jury said in this bell weather case.

    2013 LX 570 2010 LS 460 2002 Tacoma 4x4

  • steverstever YooperlandPosts: 40,157
    edited October 2013
    Here's a blurb with some other details. Be curious to see how many of the remaining ~300 or so cases wind up in trial.

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  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,547
    I always thought the scenario of a car going full throttle while loosing its brakes completely and negating the ignition shut-off completely and THEN coming completely back to normal by the time it gets to the dealer was simply UN-credible.

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  • houdini1houdini1 Kansas City areaPosts: 5,870
    edited October 2013
    Also throw not being able to shift into neutral in the mix.

    I can see where a loose floor mat or other loose object might interfere with the gas pedal, but even in that unlikely event you would still have a lot of options.

    2013 LX 570 2010 LS 460 2002 Tacoma 4x4

  • eliaselias Posts: 1,904
    you guys must somehow be missing all the reports of toyota settling some of these cases and paying out big $ . such as to the estate of the cop & his family who died.
    hence the idea that 'cause was poor drivers and greedy lawyers' does not seem consistent with the court results!
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,547
    You don't go to court for the truth or for justice. You go to court to outmaneuver the other guy. Whoever can best work the system and is clever enough, wins.

    So the settlement has nothing to do with presuming that electronics caused the UA. The two have no direct relationship, only a correlation in the lawsuit.

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  • fintailfintail Posts: 33,568
    Or it was cheaper than paying an overpaid legal team to work for months on a case decided by a jury of rubes.

    The cop case doesn't seem connected to the usually over-50 "drivers" of runaway Camrys and Prius.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,547
    no but I still find the odds of such a claim astronomical in unlikelihood.

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  • fintailfintail Posts: 33,568
    edited November 2013
    I can probably buy floormat + panic in the cop tragedy, but in the rest, it all seems like driver error.
  • srs_49srs_49 Posts: 1,394
    Have you read some of the reports from the Oklahoma trial that Toyota lost? Some heavily redacted parts of the testimony by Michael Barr (who's company was one of the ones that examined the source code for the ECU in a highly secured clean room environment) state that they were able to duplicate a UAE event with a Camry running on a treadmill or dynamometer with a simple single bit-flip in one of the critical software routines.
  • fintailfintail Posts: 33,568
    Did they get this on video, and if so, is it available for public viewing? I'd think such data would be valuable to the market in general. In this day and age when anything can be recorded in numerous ways, data counts.

    I'm very leery of trials for such things when the people making the decision usually have zero knowledge of cars, driving, engineering, et al.
  • srs_49srs_49 Posts: 1,394
    I'm sure they got it on video, but almost certainly it's not for public viewing. Most of what came out of that clean room study of Toyota's (Denso's actually, I believe) software is under heavy wraps. Toyota/Denso is claiming IP rights and protection.

    Evidently, the courtroom in Oklahoma had to be emptied at times when testimony was going to cross certain lines. Even much of the publicly available testimony has been heavily redacted in some places to protect the guilty, and corny terms such as "Software Routine X" used in place of the real name, real variable names replaced with a generic VarY, that sort of stuff.
  • stevedebistevedebi LAPosts: 3,784
    "Have you read some of the reports from the Oklahoma trial that Toyota lost? Some heavily redacted parts of the testimony by Michael Barr (who's company was one of the ones that examined the source code for the ECU in a highly secured clean room environment) state that they were able to duplicate a UAE event with a Camry running on a treadmill or dynamometer with a simple single bit-flip in one of the critical software routines. "

    I'm afraid I find your comment unclear. Are you saying the bit flipped due to software error, or they manually flipped the bit to cause the UAE? The first would be a major problem, the second simply a side note that the code is (correctly) not flipping the bit. But bits don't flip themselves, and if they observed that under debugging conditions, they could easily find out what happened - and issue a software fix. I have not read of any software fixes...
  • srs_49srs_49 Posts: 1,394
    No. A bit flip caused by an external event - a soft error. They simulated such a event by manually flipping the bit.

    Bit flips are not all that uncommon given the small feature sizes of todays memories. The problem is that Toyota/Denso did not provide error detection and correction (EDC/ECC) on their memories or registers, even those holding critical variables. This is a no-no for safety critical applications, particularly when those techniques are widely known and employed in other areas.

    The bit-flip mentioned caused the software module/routine to die.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,547
    And causes the brakes to fail and the ignition to not shut off, all simultaneously?

    I'm all ears to hear how that happened.

    Have you all noticed that it isn't happening anymore? Now why is that?

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  • busirisbusiris Posts: 3,490
    In my mind, this topic is approaching the level of the JFK probe.
  • srs_49srs_49 Posts: 1,394
    edited November 2013
    All of this came from EETimes.com - a trade newsletter for electrical and software engineers. You can probably go to that site, do a search for "Toyota" and you'll find hits to their articles on that case.

    Here's the one that discussed the dynamometer test of an '05 and '08 Camry.

    http://www.eetimes.com/document.asp?doc_id=1319966

    And one of the more telling excerpts from that article:

    However, we have confirmed in other vehicle testing that I'll talk about later, that if the incident begins with the peddle, [sic] brake peddle [sic] pressed at all, even lightly then the unintended acceleration will continue, potentially, forever unless the driver tries the risky thing of letting go of the brake while the car is driving away with him.

    In this case, the driver has to do something counterintuitive - release the brake, then reapply it while the car is accelerating.
  • srs_49srs_49 Posts: 1,394
    edited November 2013
    In my mind, this topic is approaching the level of the JFK probe.

    I find it rather fascinating!
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,547
    Still doesn't explain the brake *failure*. You can stop a car that has the pedal pressed all the way to the floor. It may not be pretty but you can do it.

    Nor does it explain the inability to shut off the ignition.

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  • srs_49srs_49 Posts: 1,394
    The brake failure and inability to shut off the ignition are almost moot points now. The bottom line from a legal standpoint is that the testimony showed that there were flaws in the design of the ECU, and that those flaws could lead to unintended acceleration. Whether or not there are ways the UA condition could have have been ameliorated/worked around is almost beside the point.
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