Witnesses at the first of three Congressional hearings on Toyota’s recall problems testified that they believe they have found a possible additional cause of unintended acceleration in Toyotas, one that has to do with the vehicles’ electronic throttle control systems.
David Gilbert, a professor of automotive technology at Southern Illinois University, said he had uncovered a potential for a short circuit that could undermine the car’s built in safety checks.
“What this does is this opens the opportunity to have other problems occur without detection,” he said.
Toyota Motor U.S. sales chief Jim Lentz said that an engineering consulting firm hired by Toyota, Exponent, Inc., was able to replicate the situation created by Gilbert both in a Toyota vehicle and in a competing vehicle.
Gilbert spoke shortly after Rhonda Smith, a Lexus owner who experienced an episode of high-speed unintended acceleration in her ES350. The car revved out of control shortly after she entered the highway, she said, and neither the brakes nor shifting the car into neutral or reverse brought it to a stop.
“After six miles, God intervened,” she said, and she was able to bring the car to a stop.
Representatives of both Toyota and National Highway Traffic Safety Administration told her that what she had experienced could not have happened, she said.
“I was labeled a destructive lying idiot,” she said.
The system used on Toyota relies on two separate sensors connected to the gas pedal and another pair connected to the throttle valve itself.
In order for the system to work each sensor in a pair has to match. If they don’t match in the proper way, an on-board computer immediately senses that as a problem and the engine power is immediately reduced to idle or, in some situations, it’s shut off altogether.
Gilbert said that he overrode that safety feature, which would have allowed faulty pedal signals to be sent to the engine with no problem being detected by the car’s on-board computer.
Toyota has raised questions about Gilbert’s tests and its application to real-world circumstances. The carmaker has invited Gilbert to demonstrate the problem for them after Toyota’s own engineers were unable to replicate the situation in an earlier test.
The problem could, theoretically, be caused by a manufacturing defect in the sensors, Gilbert said.
Gilbert said he was unable to create a similar problem in cars by other manufacturers, including General Motors and Honda. Those cars use more stringent error-checking systems in their cars, Gilbert said.
“We are confident that no problems exist with the electronic throttle control system in our vehicles,” Toyota Motor U.S. sales chief testified. “We have designed our electronic throttle control system with multiple failsafe mechanisms to shut off or reduce engine power in the event of a system failure.”
After revealing that Toyota’s consultants had been able, late Monday night, to replicate Gilbert’s results, Lentz expressed skepticism that “crossing wires” reflected a real-world issue.
“Of these five attorneys who have sponsored your research how many of these law firms, right now, are suing Toyota?” Buyer asked Sean Kane, president of Safety Research & Strategies.
“I believe every one of them represents the voice of a victim of the problem we are dealing with today,” Kane replied.
Ray LaHood, secretary of the U.S. Transportation Department, told the subcommittee that the National Highway Traffic Safety Administration is going to investigate the possibility that electronic defects are to blame for some of Toyota’s acceleration problems.
FULL STORY: http://money.cnn.com/2010/02/23/autos/Toyota_recall_hearing/index.htm
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