Debugging electromechanical problems in systems with computer code involves a very complicated error finding protocol. When politicians ask for simple answers, they don't appreciate the number of possible defects that could potentially be causing the sudden acceleration problem.
The fact that sudden acceleration was replicated by a Consumer Reports engineer or a Southern Illinois University engineer does not mean that these are the actual or even the most likely causes of the problems in real world conditions.
http://abclocal.go.com/wls/story?section=news/consumer&id=7234106http://www.autoblog.com/2010/02/22/video-smoking-gun-abc-news-expert-recreates-sudden-acceleratio/5The actual engineering forensics still require finding the cause of the problem in the vehicles that actually crashed and replicating this to determine the most likely set of variables that could cause it.
Otherwise, you have the engineering equivalent of a witch hunt were a scapegoat is identified without actually finding the real causes or culprits.
Members of Congress are generally lawyers and politicians, not engineers. But they are launching investigations and creating policies that have a direct impact on the designers and builders of incredibly complex vehicles -- there are 20,000 parts in a modern car -- so there are some basics they should understand. Chief among them: The only way to credibly figure out why something fails is to attempt to duplicate the failure under observable conditions. This is the engineering method.
Toyota is facing an incredibly difficult task. Here's what it knows: It has received hundreds of complaints about unintended acceleration in its vehicles in recent years. People have died in these crashes. Over the same period, hundreds more have died in Toyota crashes that had nothing to do with runaway acceleration. After that, it knows nothing.
Then follows a process of elimination. It's not dissimilar to a doctor diagnosing an illness: Take a thorough reading of the symptoms, then begin eliminating causes. Treat what you think is the illness. If it doesn't go away, treat your second guess at the illness.
If the electronic throttle control is the suspected culprit, it is removed from the Lexus and set up on a test bench, where it is affixed with monitoring equipment and a power source. You give it juice and see what happens; see whether there are drops or surges in micro-voltage that could lead to runaway acceleration, for instance.
...another possible cause of the runaway acceleration: a software glitch.
Frank Ahrens: Why it's so hard for Toyota to find out what's wrong
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