As Toyota rolls out fixes for sticky gas pedals, the automaker is coming under scrutiny from federal investigators who say the faulty pedals are not the only cause of sudden acceleration. 

Electronic defects may also have contributed to the problem, say investigators and independent safety experts. Federal safety regulators have begun an investigation into Toyota’s electronic throttle control system, which connects the accelerator pedal to the engine via sensors that send electric signals, rather than a mechanical cable.

“It’s not just sticking gas pedals,” says Byron Bloch, an independent auto safety expert. “Toyota, which does a pretty good job in many ways, made a bad decision when they went to electronic throttle control. They should have adopted more safety measures and they didn’t. And their customers and company are suffering as a result.”

Toyota maintains that its electronic throttle control system is not to blame.

“Through many investigations over a period of many years, Toyota has never found a problem with the electronic throttle control system that could lead to unintended acceleration,” says Brian Lyons, safety and quality communications manager at Toyota, USA. “The results of those investigations recently have indicated pedal entrapment and sticky pedal [are to blame].”

Doubts about cause
But a recent investigation by the Los Angeles Times also casts doubt on Toyota’s decision to blame sudden acceleration on the gas pedal defects.

Motorists have to date lodged more than 2,000 complaints of sudden acceleration in Toyota and Lexus vehicles over the last decade, according to the Times report. The problem has led to 19 deaths and 815 vehicle crashes since 1999, as well as global recalls numbering in the millions.

Complaints of sudden acceleration soared with the introduction of electronic throttles in Toyota vehicles in 2002, the Los Angeles Times report says. And of the 2,000 complaints of sudden acceleration in Toyota vehicles since, only 5 percent blamed sticking gas pedals, according to the report.

The National Highway Traffic Safety Administration (NHTSA) has conducted eight investigations into sudden-acceleration problems in Toyota vehicles in the past seven years and none of them have identified a sticking pedal as a cause, the report adds.

Moreover, the maker of the faulty gas pedals, Indiana-based CTS Corp., claims that its product has been unfairly blamed.

“The problem of sudden unintended acceleration has been reported to have existed in some Lexus vehicles and Toyota vehicles going back to 1999 when CTS did not even make this product for any customer,” the manufacturer said in a statement last week.

No proof on throttle control, either
Still, experts caution that no evidence has yet been found linking the throttle control system to sudden acceleration.

“NHTSA has investigated [electronic throttle control] and found nothing,” says David Champion, senior director of Consumer Reports' Auto Test Division. “A lot of people are saying this is the issue. Well, show me.”

A congressional inquiry headed by Rep. Henry Waxman (D) of California and Rep. Bart Stupak (D) of Michigan will look into the source of the accelerator defect and determine whether Toyota has taken adequate measures to fix it. The Energy and Commerce Committee, chaired by Representatives Waxman and Stupak, will hold a hearing on Feb. 25.