Toyota - no flaw found with safety electronics

For its part, Toyota has hired Exponent and has provided financial assistance to Stanford's auto safety Centre.

Toyota and Exponent said they were continuing to test other explanations for unintended acceleration that would go beyond the problems it has identified.

Separately on Monday, a Flint, Michigan area judge ordered Toyota's top two U.S. executives -- Yoshi Inaba and Jim Lentz -- to appear for questioning for lawyers for the family of a woman who was killed in a Camry crash in 2008.

Guadalope Alberto died when her 2005 Camry surged out of control. Her family is suing Toyota. Lawyers for Toyota had argued that lower-level executives should be allowed to answer questions from Alberto's lawyer, but the judge ordered Lentz and Inaba to appear, said Hike Heiskell, a lawyer for the Alberto family.

Also on Monday, Rep. Edolphus Towns, a New York Democrat who chairs the House Oversight and Government Reform Committee, asked Toyota to turn over a letter Toyota employees in Japan reportedly sent to management in 2006 detailing safety concerns. Towns made the request in a letter sent on Monday.

The letter, which was reported by the Los Angeles Times, said employees had warned Toyota that a failure to address quality concerns could ultimately threaten the company's survival.

Toyota had no immediate comment.

(By Kevin Krolicki and Bernie Woodall; editing by Carol Bishopric)