WASHINGTON — Toyota Motor Corp. said Monday it had fixed about 3.7 million vehicles in the United States as part of its massive safety recalls, citing progress in rebuilding its reputation for safety. The world's largest automaker said in a progress report that it had aggressively responded to safety problems at the urging of its president, Akio Toyoda, and top company officials.

Customer complaints about unintended acceleration made to its consumer hotline have fallen considerably since April. The automaker said it was expanding the role of engineering teams created to investigate problems with unintended acceleration to include other problems raised by owners.

And Toyota officials said they had reviewed 4,200 vehicles in which owners alleged problems with unwanted acceleration and did not find any link to electronic problems – a possible culprit that has been raised by safety advocates.

“I have a direct line to Akio Toyoda on safety issues and I believe we demonstrated in recent months that we have the authority to act quickly to address any safety issues that emerge,” said Steve St. Angelo, Toyota's chief quality officer for North America.

Toyota has been working to repair its reputation for safety in the wake of more than 10 million recalls worldwide for problems such as faulty gas pedals, floor mats that can trap accelerators and problems with its Prius hybrid. The problems are still under review by the government.

The company said about 80 percent of the 2.3 million vehicles recalled for sticking pedals have been fixed and nearly 58 percent of the 5.4 million vehicles with gas pedals that could become trapped in floor mats have been repaired.

Toyota said it was receiving about 800 phone calls a week in April about unintended acceleration complaints but its consumer hotline now receives about 150 phone calls per week.

U.S. regulators fined Toyota $16.4 million earlier this year for failing to promptly tell the government about its car defects. In August, the Transportation Department said its preliminary investigation had not found any new causes of the problems involving sudden acceleration beyond two previously identified in the recalls: floor mat entrapment and sticking accelerator pedals.

Toyota officials said they had not received an update from the Obama administration on the progress of the investigation being conducted by engineers with NASA and the National Highway Traffic Safety Administration. The government has said it expects to complete its review this fall.

“We're very confident [as] to our analysis that they won't find any electronic problem with our electronic throttle control system. However, they may find areas where we can improve our system,” St. Angelo said.

The government has received about 3,000 complaints about sudden acceleration and estimated the problem could be involved in the deaths of 93 people over the last decade.

AP Business Writer Dan Strumpf in New York contributed to this report.