Toyota Disputes Link Between Electronic Throttle Systems and Acceleration Claims

Mark Rechtin, Automotive News

LOS ANGELES — Toyota Motor Corp. launched a media offensive today that attempted to debunk the possibility that its electronic throttle control could be a root cause for unintended acceleration claims.  “There is no evidence, nor any sign, that electronic throttle control systems have been involved,” said Toyota spokesman John Hanson.  In a 90-minute conference call, Toyota engineers displayed internal videos that showed how Toyota “fail-safe” systems would not allow a vehicle to accelerate on its own.

The automaker also showed documents of how its internal electromagnetic interference testing exceeds U.S. and European regulatory minimums. Some claimants have stated that certain radio frequencies made their Toyotas accelerate out of control without warning.  Paul Williamsen, manager with the automaker’s University of Toyota training center, said that once any of many hard-coded central processing units within the car register a fault involving the throttle sensor or throttle pedal, it will return the engine speed to idle or shut off the engine altogether.

“We have the highest-order of redundancy and error checking of any system,” Williamsen said of the electronic throttle control system. “Our fail-safes work in four milliseconds. We’re talking inches of vehicle travel, not vehicle lengths.”

Williamsen said that on-board diagnosis systems will register trouble codes that should help illuminate throttle problems. However, in the case of unintended acceleration claims, the diagnosis system cannot determine if the fault lay with the car, or perhaps with a driver who mistook the gas pedal for the brake.  “It is apparent there were some instances of misapplication” of the gas pedal, Hanson said. “We are investigating what the other options might be.”

However, an ABC News report quoted Southern Illinois University professor Dave Gilbert as saying he had found a flaw in Toyotas that prevents the vehicle from registering a fault and activating its fail-safe system.  Toyota did not directly comment on the ABC report. The automaker has maintained that unintended acceleration in its vehicles is tied to sticky gas pedals or floor mats interfering with the pedals’ movement. Both issues have been addressed by recalls.

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