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Author Topic:   Electronic Throttle: An Outlier Decision
jimh posted 10-25-2013 12:22 PM ET (US)   Profile for jimh   Send Email to jimh  
A jury in Oklahoma recently returned a verdict in a civil lawsuit that found Toyota liable for damages and injuries sustained in a car crash due to sudden acceleration of one of its cars controlled by an electronic throttle system.

After a three week long trial, it took only a short deliberation for the jury to find that Toyota's 2005 CAMRY was equipped with a defective electronic throttle. The jury found for the plaintiffs in the amount of $3-million, and also found that there was "reckless disregard" by Toyota, which could permit a much larger award for punitive damages.

The issue--and here I use that word with its actual meaning--of the Toyota electronic throttle control and sudden acceleration of the CAMRY has been fought before, resulting in many settlements.

Toyota has paid out $1.6-billion just to settle a class action lawsuit, brought on behalf of owners of the affected cars who had not been injured but who sought compensation because the value of those cars was reduced by the cloud of concern about the many cases of sudden acceleration being widely reported.

The Oklahoma jury apparently was not aware of or perhaps did not consider or could not consider a finding by the USA Department of Transportation, which in 2011 said a 10-month investigation into the sudden acceleration of Toyota cars was not due to any defect in the electronic throttle control system. The DOT finding was that sudden acceleration was caused by:

--improperly installed floor mats,

--sticky pedals, or

--driver error.


jharrell posted 10-29-2013 04:45 PM ET (US)     Profile for jharrell    
Investigations into the source code and hardware design shows extremely poor engineering. Speculating what the jury considered or did not consider and dismissing their verdict would not be wise.

Very interesting and disturbing details on the e-throttle design in question can be found here: Toyota-s-killer-firmware--Bad-design-and-its-consequences

andygere posted 10-29-2013 06:16 PM ET (US)     Profile for andygere  Send Email to andygere     
So what's the connection to Boston Whaler boats? Is there some conclusion to be drawn about marine electronic throttle systems from this court case?
jharrell posted 10-29-2013 06:29 PM ET (US)     Profile for jharrell    
I would imagine the connection is related to the mistrust of electronic engine controls that are becoming more popular in outboards like those found on many Whalers. I am however just speculating.

For me what enlightening in this case is how bad both the hardware and software design is from such a large and well respected manufacturer. The conclusion I draw is that we have no idea how good or bad the design is of any electronic throttle since it is very difficult to obtain the source code. If a mechanical throttle is poorly design, it may be more easily seen since the device can be taken apart, whereas compiled software is very nearly a sealed black box.

Perhaps we don't want to know how the sausage is made, I believe electronic throttles have a good record overall, and I prefer them. As a software engineer by trade, these details are very disturbing.

Jerry Townsend posted 10-29-2013 09:10 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
I also questioned the Whaler connection, but suspect that it stems from the electronic control systems we hear about today.

But Jim's referrenced link references the NASA evaluation of Toyota's control system. Given previous associations with NASA, I have a lot of respect for their control system expertise.

While the reference given by jharrell addresses the evaluation and report of a consultant firm owned/chaired/et al by a "developer", author, professor (of what ? - economics? education? history? - or some technical field?).

But having said that - I question the 3 reasons for the failures given by the NASA evaluation report. There are other "things" involved in a control system - such as servo motors, potentiometers, et al - which may have failed also. Neither evaluation mentioned reviewing the Toyota test data

Regarding the source code - which is just the communication means of engineers/programmers to communicate with the computer. There is nothing wrong with C (or C+, C++) - but I am not a software engineer. They got the job done - but heck, Fortran got it done too. There are undoubtedly other languages used today. Wow - those languages almost seem foreign - as I retired some 19 years ago. ---- Jerry/Idaho

jimh posted 10-29-2013 09:15 PM ET (US)     Profile for jimh  Send Email to jimh     
Electronic throttle controls are used on--mandatory on--VERADO engines and certain models of Yamaha, and possibly others. Electronic throttle controls are options on OptiMax and E-TEC outboards.

Electronic throttles don't seem all that complicated. Indirect control of aircraft--fly-by-wire--has been in use for decades. Yet there still seems to be some apprehension about using electronic throttle controls.

jharrell posted 10-29-2013 09:34 PM ET (US)     Profile for jharrell    

The language used is not in question. I would be very surprised if it weren't written in C as most embedded systems of today are. The disturbing details are lack of ECC ram, not double storing and checking critical variables and numerous potential stack overflows, race conditions and buffer overflows. These problems are not particularly language dependent, but surprising in such a critical piece of software.

These case was specifically about a 2005 Camry ECU, it is not clear what controller NASA looked at and if it they where comparable.

You may doubt the motives of the source of information, but so long as the facts where not fabricated they stand without bias.

andygere posted 10-30-2013 10:34 AM ET (US)     Profile for andygere  Send Email to andygere     
It would be interesting to compare the rate of failure of mechanical throttle and shift controls for outboard motors to the rate of failure of electronic controls. Unfortunately, I doubt such data is publicly available. Each system has a different type of failure mode, and perhaps because the failure mode of an electronic control is not always immediately visible, there is some inherent distrust in them, even if they turn out to be statistically more reliable.
jimh posted 11-01-2013 10:45 AM ET (US)     Profile for jimh  Send Email to jimh     
In one of the comments that follow-up to the article (linked above, see the EDN article and the comments from user "solutionseeker") about the USA DOT investigation using NASA scientists, there is an assertion that the NASA people were subjected to political pressure from DOT to come up with a fault-free assessment of the Toyota throttle control system. Such political pressure seems entirely believable. One has only to read about the Challenger Shuttle Disaster investigation to become acquainted with the political pressure that can be exerted. In that investigation, it was only the stature of a Nobel-prize winner, Richard P. Feynman, and his refusal to go along with the committee's consensus, that allowed inclusion into the investigation's report--and then only as an annex-- of very critical findings concerning the handling of the problem by NASA.

As Feynman wrote: "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled."

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