Toyota-Hired Firm Finds No Problem With Electronic Throttle

February 15, 2010
2010 Toyota RAV4

2010 Toyota RAV4

A Toyota-funded test of vehicles has failed to find issue with the automaker's electronic throttle system, which some safety advocates have accused of being linked to widespread reports of unintended acceleration in Toyota and Lexus vehicles.

Back in September, Toyota recalled 3.8 million Toyota and Lexus vehicles for issues with mismatched floor mats that might cause dangerous unintended acceleration, then more than three weeks ago, Toyota initiated a separate recall for an issue with throttles in 2.3 million vehicles, including the 2010 Toyota RAV4. About 1.7 million vehicles are affected by both recalls.

This is not to be confused with the brake-related recall covering the 2010 Toyota Prius and 2010 Lexus HS 250h—although the 2004-2009 Prius is among the many vehicles covered by the floor mat recall.

The latter of the two accelerator recalls was linked to a throttle mechanism that would become sticky due to exposure to moisture, along with a combination of age and wear.

Toyota had an external engineering and scientific consulting firm—Menlo Park, California–based Exponent—conduct an independent analysis of the so-called Electronic Throttle Control System with intelligence (ETCS-i), and the firm was "unable to induce inintended acceleration in any of the ETCS-i equipped Toyota and Lexus models it tested," according to Toyota.

"In all cases, the vehicles either behaved normally or entered a fail-safe mode where engine power was significantly reduced or shut off," stated Toyota in a release on the matter.

Many safety advocates in recent weeks have criticized Toyota's lack of another line of defense, in the way of a so-called smart throttle that would automatically override the throttle signal if the brake pedal is pressed. Toyota has confirmed that it will be adding such a feature to future vehicles.

According to the Wall Street Journal, which obtained a copy of Exponent's study, the firm's study said that "Exponent has so far been unable to induce, through electrical disturbances to the system, either unintended acceleration or behavior that might be a precursor to such an event, despite concerted efforts toward this goal."

A total of six Toyota and Lexus vehicles were studied in Exponent's initial test, according to the WSJ, with analysis including electronic "anomalies" along with tests for sensitivity and "noise" induced on individual components. When abnormalities were detected, the system reduced power rather than increased it, according to Exponent, in what Toyota describes as a limp-home mode.

"Exponent's testing and evaluation is ongoing," added Toyota, confirming that the affirmation involved testing on multiple vehicles and components, in normal and abnormal conditions.

2010 Toyota Avalon

2010 Toyota Avalon

The electronic throttle system, called a drive-by-wire system by some because it does away with the traditional cable connection between the gas pedal and throttle body, has been installed into most Toyota vehicles now for much of the past decade.

Today, the Toyota Motor Corp. said that it is looking at new ways of assuring quality and reliability in its vehicles, which might involve some radical changes in the way in which the company develops its vehicles and how transparent it is with the public about design changes.

For a complete list of vehicles covered by each accelerator-related recall, along with an index of stories to date and a timeline for breaking news on the issue, visit Toyota And Lexus Recall: Everything You Need To Know.


[WSJ, Toyota]

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