Toyota Unintended Acceleration and the Big Bowl of "spaghetti" Code(2013)
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Read the primary article or dive into the live Hacker News thread when you're ready.
“The Car Hacker’s Handbook” may be of interest as a first step review, but honestly I just dove in with Ghidra and just .. didn’t ever stop. YMMV :)
Make of that what you will.
https://betterembsw.blogspot.com/search/label/Toyota%20UA
The only thing they did in the recall was the same floor mat anchor as so many other cases.
"NASA engineers found no electronic flaws in Toyota vehicles capable of producing the large throttle openings required to create dangerous high-speed unintended acceleration incidents. The two mechanical safety defects identified by NHTSA more than a year ago – “sticking” accelerator pedals and a design flaw that enabled accelerator pedals to become trapped by floor mats – remain the only known causes for these kinds of unsafe unintended acceleration incidents. Toyota has recalled nearly 8 million vehicles in the United States for these two defects." -- transportation.gov
Cosmic rays and other wild theories over the simple theory of driver error. Even with a stuck throttle, the brakes will still stop a car (not to mention shifting into neutral still works).
I don't know enough about 2005 Camry's though, so I wouldn't speculate much further than that.
(Apparently the Rimac Nevera, with about 2000hp, can accelerate faster than it brakes. So that one might be the only exception. So unless you're driving a 2000hp car, the brakes will always overpower the engine, that is not debatable.)
Brake fade is irrelevant here. Brakes fade when overheated beyond their operating range, either due to fluid boiling and/or the pads overheating. This is nearly impossible to achieve in street driving, but can be experienced on the race track. None of the claimed acceleration accidents involved extreme repeated braking prior to the incident.
This "scandal" was never about mechanical failures. It was almost certainly about driver error and mass hysteria.
As for Toyota settling, had this been Ford or Chevy, the government wouldn't have had the appetite to go after them for what was always a non-issue. It was just less expensive for Toyota to fix floor mats and pay a billion to put it all behind them.
The issue was not that no one found the flaw, it’s that no one could prove it wasn’t there.
Are cars since then required to have formally verified codebases, or is "no one could prove [there are no bugs]" still true?
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Trying to evaluate what happened based on observation of events alone and stats, in absence of a formal proof of issue or non-issue... the cars didn't just disappear overnight so if there was such an issue... where did it go?
Toyota issued multiple engine controller updates. All mfgs do, all the time.
There are no changelogs.
It would also matter what their typical car lifecycle is, it could have been just before refresh so only effected a couple years.
It could have also been bad floor mats.
We’ll never know - but the point is, that their code was so bad you COULD never know.
You should ask a mechanic's opinion.
You and I would change a constant and recompile. They will just splat location 0x239A
Nothing wrong with source-file-level statics, you're bound to use them
This story is like Baba Yaga, it comes out from the shadows to scare people every now and then, but Barr’s theory has the interesting property that the ECU would be cleared by the error and so there could never be evidence of the event as he postulated.
http://nepp.nasa.gov/whisker/reference/tech_papers/2011-NASA...
https://www.scientificamerican.com/article/solar-storms-fast...
Just to give perspective on the bit flip probability. ECC ftw!
After all, was the error in the first line a typo on my side, or a single-bit upset?
A while ago some researchers registered off-by-one-bit domain name typos, which due to physical key positioning were unlikely to be the result of genuine mistyping. I can't find a reference right now, but I recall them getting quite a lot of queries!
I have left memtest86+ running on a few dozen GB of memory for several days during burn-in testing, definitely more than enough to pass the "once per 256MB per month" threshold, and did not encounter any errors.
https://www.sciencedirect.com/science/article/abs/pii/S03790...
My conclusion is that it's mosty (scientific) clickbait.
(96 points, 106 comments) https://news.ycombinator.com/item?id=10437117
(152 points, 145 comments) https://news.ycombinator.com/item?id=9643204
[1] https://news.ycombinator.com/item?id=46183657