WASHINGTON -- The US National Highway and Transportation Safety Administration and NASA this week issued their final report absolving Toyota's vehicles of malfunctions that caused unintended acceleration.

The 10-month study produced a pair of reports, with the official report from the NHTSA concluding that Toyota’s electronic throttle control system does not have design or implementation flaws that could reasonably be expected to cause UA events involving large throttle openings as described in consumer complaints to NHTSA.

However, in NASA's 177-page report (also on the site), the agency did detect the presence of tin whiskers, and found in a small number of instances that malfunctions occurred. "Through microscopic analysis of a failed pedal obtained from a field incident, certain resistive faults can result from the presence of tin whiskers within the accelerator pedal position sensor. In vehicles with potentiometer sensors (MY 2002-2006), NASA found that this kind of resistive short generally produces a DTC, warning light, and failsafe operation, but results in different vehicle responses depending on the subsequent operation of the vehicle following the occurrence of the fault. In the field incident in which the pedal examined by NASA was involved and in the only other three incidents that appear to be of that nature found in the VOQs, the resistive short triggered a DTC and fail-safe operation."

NASA noted that the potential for unwanted acceleration in this scenario was remote and the effect miniscule, in each case, the malfunctioning vehicle was repaired without damage or injury.

NHTSA said it will begin preliminary research on the reliability and security of electronic control systems, including examining existing industry and international standards for best practices and relevance to automotive applications.

The full report can be downloaded here.

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