CBS News Exclusive: Toyota Study Disputes Acceleration Problem
CBS News Investigative Correspondent Sharyl Attkisson has obtained a confidential copy of the Exponent report, dated Feb. 4, 2010.
Exponent Report obtained by CBS News
The report attempts to exonerate the electronic throttle controls system in Toyota vehicles.
"We are confident that no problem exists with the electronic throttle controls system in our vehicles," Lentz said.
The Exponent report concluded that "when a fault was imposed, the vehicle entered a fail-safe mode consistent with descriptions provided in the technical manuals for Toyota and Lexus vehicles."
However, some members of Congress criticized the limited scope of the tests as well as Exponent's financial ties to Toyota. Exponent has worked with Toyota in the past and claims many other corporate giants as clients.
Toyota called the Exponent testing "an initial progress report." Congressional experts say the Exponent review did not follow sound scientific method:
-- categories of testing, such as electromagnetic interference and radio frequency interference were not addressed
-- only one of the seven vehicles used in the study was on the recall list
-- the study did not examine a single vehicle that had experienced sudden, unintended acceleration
Tracking down an electrical problem can be far more difficult, expensive and time-consuming than finding a mechanical problem.
Electrical problems can have more than one source, and they can come from inside or outside the car. Mechanical problems often leave clues such as physical damage, where electronic troubles can be hidden in software or leave no trace at all.
House investigators who reviewed Toyota's customer call database found that 70 percent of the complaints of sudden acceleration were for vehicles that are not subject to the recalls over floor mats or sticky pedals.
Rep. Bart Stupak, D-Mich., chairman of the subcommittee, said Toyota "misled the American public by saying that they and other independent sources had thoroughly analyzed the electronics systems and eliminated electronics as a possible cause of sudden unintended acceleration when, in fact, the only such review was a flawed study conducted by a company retained by Toyota's lawyers."
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Under questioning before the House committee, Lentz maintained that so far Toyota, and Exponent, found no evidence of problems with the ETCS-i system. But he was careful to limit his assessment to "what we know today."
"I don't think any manufacturer knows 100 percent exactly what is causing problems," Lentz said. "My feeling is that these two fixes fix what we know of."
The key words are "what we know of," and Toyota is taking steps to improve its quality control and investigate what it doesn't know. An advisory board is being formed by the end of March that Lentz said will have "total independent control" to investigate further the causes of sudden unintended acceleration.