Toyota Motor Corp's president pledged to cooperate fully with U.S. government officials investigating safety problems on Wednesday as he prepared to tell a congressional panel that the automaker had let standards slip in its rise to the top.

Akio Toyoda's appearance before the panel marks the dramatic peak so far of a safety crisis that broke a month ago with a series of recalls over unintended acceleration and braking problems that now includes more than 8.5 million vehicles globally.

The chairman of the U.S. House Oversight and Government Reform Committee opened the hearing by recounting a horrific crash that sparked the big recalls and blasting Toyota for boasting of saving $100 million by limiting a 2007 recall of floor mats implicated in the fatal accident.

Toyota either ignored or minimized reports of sudden acceleration, said oversight panel chairman Edolphus Towns, a Democrat from New York.

Toyoda arrived at a congressional office building on Wednesday morning, hours before his scheduled testimony. He read a short statement in Japanese to waiting reporters.

This is a very valuable opportunity to appear today and I am very grateful to Congress for this invitation, said Toyoda, who was accompanied by Yoshi Inaba, Toyota's chief of North American operations.

Safety is our top priority and I intend to cooperate fully with the U.S. government, he said.

Toyoda, who has appeared uneasy with the global spotlight in the past month, waited for a translator to deliver his short statement in English and then walked briskly off when prompted by an aide, declining to take questions from reporters.

Toyota, founded by Toyoda's grandfather, now faces a criminal investigation and a securities probe in the United States as well as unresolved questions about hundreds of incidents of unintended acceleration reported by consumers.

Toyoda is one of eight witnesses set to appear on Wednesday.

The same panel will hear from a relative of Mark Saylor, an off-duty California Highway Patrol officer who was killed last August, along with three members of his family, when the Toyota Lexus sedan he was driving sped out of control.

Toyoda and Inaba are due to appear after U.S. Transportation Secretary Ray LaHood.

David Strickland, head of the National Highway Traffic Safety Administration, will attend but not appear as a witness. LaHood asked to take all questions to the government, said a spokesman for the committee.

In his prepared testimony, Toyoda extended his condolences to the Saylor family and said he was deeply sorry that the company had allowed its standards for quality to slip during a period of fast growth over the past decade.

Toyota has promised internal reforms intended to increase attention to safety and ensure that future recalls happen more quickly in response to consumer complaints.

'A DECADE OF NEGLECT'

Darrell Issa, the ranking Republican on the oversight panel, said regulators at the National Highway Traffic Safety Administration had to face as much scrutiny as Toyota.

We're going to hold NHTSA accountable for a decade of neglect just as much as Toyota, said Issa, who has been outspoken about the need for Toyoda himself to appear before Congress.

He's the only person who can bring real change on behalf of his company, he told Reuters Insider. Issa's California district neighbors the San Diego site of the Saylor crash.

Earlier on Wednesday, Japan's transport regulator said the government would look into 38 reports of unintended acceleration with Toyota cars over three years, raising the pressure on the world's top automaker.

In order for Toyota to manage growth better, some analysts have said the company needs to slow down its product development cycle, easing pressure on engineering teams that have been stretched to the breaking point.

Aizawa Securities analyst Toshiro Yoshinaga said taking that step would not necessarily hurt Toyota.

The replacement cycle for automobiles is getting longer globally. It is quite natural if the (Toyota) development cycle gets a little longer as well, he said.

The first day of Congressional hearings on Toyota's safety crisis featured testimony from a Tennessee couple who said their Lexus raced out of control and an Illinois professor who said he had identified what appeared to be a flaw in the design of Toyota's accelerator control system.

Toyota's U.S. sales chief, Jim Lentz, said on Tuesday he was not totally sure that the company's recalls to date would address all of the cases of unintended acceleration.

Under questioning, he agreed that about 70 percent of consumer reports of such incidents were not linked to the problem with accelerator pedals becoming jammed open by loose floor mats or because of a glitch in the pedal itself.

Toyota's recalls focus on those two problems. The automaker has said it will cooperate with a wider probe led by U.S. safety regulators into whether electronic problems could be to blame for episodes where drivers report that its cars have surged forward.

LaHood, the U.S. Transportation secretary, pledged on Tuesday that safety regulators will get into the weeds in examining electronic risks for cars that are increasingly dependent on computerized controls.

(Additional reporting by Kevin Krolicki in WASHINGTON; David Bailey in DETROIT; Miyoung Kim in SEOUL; Janaki Krishnan in MUMBAI; Chisa Fujioka, Yumiko Nishitani and Junko Fujita in TOKYO; Graphic by Catherine Trevethan; Writing by Tim Dobbyn; Editing by Ian Geoghegan, Nathan Layne and Matthew Lewis)

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