|Ray LaHood, the US transport secretary, has laid to rest claims that Toyota suffered from 'electonic flaws' [EPA]
Electronic flaws were not to blame for unintended acceleration in Toyota vehicles that forced the Japanese company to recall eight million cars, a US government investigation has revealed.
The inquiry - which called on NASA scientists to examine whether the acceleration was due to faulty electronics - pointed to two previously known mechanical faults as the sole causes.
"Toyota's problems were mechanical, not electrical," Ray LaHood, the transport secretary, said on Tuesday, further clarifying that the results of a 10-month investigation backed up Toyota's claims.
The accidents, which have been linked to at least 89 deaths, were blamed on a "sticking" accelerator pedal and jammed floor mats, as the car manufacturer had originally found.
Toyota Motor said the findings "confirms the reliability" of the company's electronic throttle-control systems.
"From here on, we intend to listen to our customers even closer and to offer not only safe vehicles but vehicles that provide peace of mind," Toyota said in a statement.
Amid a number of injury reports, court cases and allegations of a cover-up, the transport department called in NASA to examine whether there was a broader problem.
The investigation analysed 280,000 lines of computer code used to run Toyota's vehicles for electronics problems and examined whether electromagnetic radiation might have played a role.
NASA investigators said electronic problems could result in throttle openings of around five degrees, but that would hardly be felt if the vehicle was already moving.
LaHood described the probe into Toyota and Lexus vehicles as "one of the most exhaustive, thorough, and intensive research efforts ever taken".
LaHood, previously an Illinois congressman, gave the Japanese company a rare endorsement.
"We feel that Toyota vehicles are safe to drive," he said.
LaHood said he had recommended his oldest daughter buy a Toyota Sienna minivan, which she did.
Toyota is struggling to recover from its damaged reputation after a series of mass recalls affecting 10 million vehicles worldwide in late 2009 and early 2010.
Toyota's North America division said it appreciated the "extensive review."
"We believe this rigorous scientific analysis by some of America's foremost engineers should further reinforce confidence in the safety of Toyota and Lexus vehicles," Steve St Angelo, Toyota's North America chief quality officer, said in a statement.
Toyota will continue "to co-operate fully with [the National Highway Traffic Safety Administration] and respected outside experts in order to help ensure that our customers have the utmost confidence in the safety and reliability of our vehicles", he said.
The company has toughened its recall policy to cover around 16 million vehicles between late 2009 and January this year.
Meanwhile, Toyota shares responded to the findings, jumping up 4.7 per cent on Wednesday morning trading in Tokyo.
The US transportation department said it would look to impose new regulations requiring brake override systems, standardised keyless ignition systems and event data recorders in all vehicles.
Amid a rapid digitisation of vehicles, the department also said it would further research the reliability and security of electronic control systems.
Toyota has paid the US authorities nearly $50 million in penalties related to the recalls.