Not sure if it's widely known how they were caught... but it was when they outsourced their translation of documents and a translator read documents and blew the whistle.
Which is why the top translation firms now offer... security!
Wow, do you have a link for that? I think this is a fascinating story in and of itself, but one of the tangential things that also interests me about it is that nobody I know in Japan (where I live) has ever even heard of this story.
A friend is a director at an interesting company that provides secure translations amongst other services to companies and has made bank since this happened. I guess it's a bit of a secret outside the industry.
'How they were caught' you mean how we discovered Toyotas suffered from "UA"? The story claims it was the incident of the off-duty highway patrol officer on a call with 911 for 4 minutes trying to stop the car before it crashed and killed all 4 occupants which blew the lid on the story.
"How they were caught" involved thousands of consumer complaints and lawsuits that continue up to the present day. Tens of thousands of unintended acceleration incidents also go unreported and unlitigated because the damage is not major enough to be worthwhile. The government auto safety regulators investigated and then closed the investigations many times due to clever manuevering by Toyota's lawyers and government-relations people. They also lied to Congress (which they have since admitted to when the DOJ investigated their cover up and fined them $1.2 billion. This story is far from over.
There have been cases where the driver attempted to switch to neutral and the car would not shift. Also, there is often not enough time to shift to neutral because the majority of instances of Toyota unintended acceleration take place in parking lots and other confined spaces, and the car hits something before the driver can react.
Here is a link to a video published yesterday with dashcam video of many sudden acceleration incidents.
https://www.youtube.com/watch?v=3oAshG36dNI
These are mainly in Korea, where dashcams are the norm, and likely to be KIA or Hyundai vehicles (they also have big software problems, apparently). Imagine driving in some of these instances of close quarters. Would you be able to shift into neutral to stop in time?
Also, Dr. Antony Anderson, who closely follows this technical issue on his blog, recently published a paper in IEEE Access about how software can be fooled by mechanical glitches such as intermittent connections:
Separately, speaking to your point about shifting to neutral, Dr. Anderson has noted that it is unreasonably risky to design a safety-critical system with the expectation that operator responses such as shifting to neutral can provide an effective failsafe. Would any of you here actually design such a system?
Which is why the top translation firms now offer... security!