WASHINGTON (AP) -- First it was gas pedals, then brakes. Now Toyota and the government are looking into complaints that the popular Corolla is difficult to steer straight, raising a new safety concern ahead of next week's congressional hearing about the automakers recalls.
But how worried should drivers be? Or is this an example of how any problem at the Japanese company now gets intense scrutiny?
The executive in charge of quality control said the company is reviewing fewer than 100 complaints about power steering in the Corolla. Toyota sold nearly 1.3 million Corollas worldwide last year, including nearly 300,000 in the United States, where it trailed only Camry as Toyota's most popular model.
The executive, Shinichi Sasaki, said drivers may feel as though they are losing control over the steering, but it was unclear why. He mentioned problems with the braking system or tires as possible underlying causes. U.S. officials are also investigating.
He stressed that the company was prepared to fix any defects it finds and that executives were considering a recall as an option, although no decision had been made.
In Japan, President Akio Toyoda said he did not intend to appear at congressional hearings next week in Washington, preferring to leave that to his U.S.-based executives while he focuses on improving quality controls. Toyoda, grandson of the company's founder, said he would consider attending if invited.
Also Wednesday, a Transportation Department official said the agency planned to open an investigation into the reports about the Corolla.
The preliminary investigation is expected to begin Thursday and involve an estimated 500,000 vehicles. The official spoke on condition of anonymity because the department had not yet notified Toyota of the probe.
In an attempt to reassure car owners, Toyota Motor Corp. said it would install a backup safety system in all future models worldwide that will override the accelerator if the gas and brake pedals are pressed at the same time. Acceleration problems are behind the bulk of the 8.5 million vehicles recalled by the automaker since November.
The company said it was placing ads in U.S. newspapers Thursday, featuring an open letter from Jim Lentz, president of Toyota Motor Sales USA, seeking to answer concerns over quality issues.
"History shows that great companies learn from their mistakes. That's why all 172,000 people working for Toyota and our dealers are doing more than ever to make things right for our customers today and for the future," it says.
The emergence of potential steering problems with Corolla presented another roadblock in the automaker's efforts to repair its image of building safe, reliable vehicles. Dealers across the U.S. are fixing accelerators that can stick, floor mats that can trap gas pedals and questionable brakes on new Prius hybrids.
Auto industry experts said any power steering troubles on the Corolla were less worrisome than accelerator pedals or brakes because drivers could still steer the vehicle, even though doing so may be more difficult.
The government investigation comes even though the automaker said it has received relatively few complaints about the popular compact.
Even so, in the United States, the National Highway Traffic Safety Administration has received a growing number of complaints from drivers about power steering on 2009 and 2010 Corollas. The numbers are small compared to Toyota's overall sales -- only about 150 reports for those two models. By comparison, there are more than 1,000 complaints about problems with 2010 Prius brakes, a vehicle Toyota has already recalled.
But the decision to investigate the Corolla offered further evidence that the automaker is exposed to heightened scrutiny of its cars and trucks.
Some Corolla drivers said they had difficulty keeping the vehicle straight, especially at higher speeds. They reported having to fight the wheel to keep the car from wandering between lanes.
Jerry Josefy, a 71-year-old retired farmer and mechanic from Grandfield, Okla., said he noticed problems with the steering on his 2009 Corolla when he drove it home after buying it last year.
He took it back to the dealer for repairs, but the steering trouble persisted. Josefy still drives the car, but said it requires constant attention to make sure it stays straight.
"It wants to wander all the time," he said. "You could have a wreck with it if you don't keep your eyes on the road."
Smaller, less-expensive vehicles such as the 2009 and 2010 Corolla use electric-assist power steering. They are usually equipped with power steering systems that are aided by a small electric motor, a system known as electric-assist steering.
The motor essentially helps align the steering wheel with the movement of the tires. The system is cheaper to install than steering systems that rely on hydraulics.
Problems can arise if the motor is out of sync with the steering wheel, which could potentially cause the vehicle to wander without any turning of the wheel, he said.
"Car companies work on it a lot," said Jim De Clerck, a professor in the Michigan Technological University's mechanical engineering department and a former General Motors engineer. "It is a pretty well-known customer-satisfaction issue."
Toyota said the steering problem could be related to the braking system or tires. Improperly aligned tires, for example, can be a source of steering complications, De Clerck said.
In Washington, the House Oversight and Government Reform Committee asked several auto insurance companies for information on whether they reported incidents of sudden acceleration in Toyota vehicles to the NHTSA.
Meanwhile, the House Energy and Commerce Committee moved its scheduled hearing up to Feb. 23, one day ahead of the Oversight Committee meeting. Toyota's Lentz and the head of the NHTSA, David Strickland, been invited to testify before the energy committee. A Senate hearing is planned for March 2.
Toyota is expected to send North America chief executive Yoshi Inaba to the hearings. Toyoda does plan a U.S. visit, mainly to speak with American workers and dealers, but he said details of his trip are not yet final.
The executives will face scrutiny in the U.S., where the Transportation Department has demanded documents related to its recalls. The department wants to know how long the automaker knew of safety defects before taking action.
Reports of deaths in the U.S. connected to sudden acceleration in Toyota vehicles have surged in recent weeks, with the alleged death toll reaching 34 since 2000, according to new consumer data gathered by the U.S. government.
Kurtenbach reported from Tokyo. AP writers Stephen Manning in Washington, and Yuri Kageyama, Mari Yamaguchi, Tomoko A. Hosaka, Malcolm Foster, and Shino Yuasa in Tokyo contributed to this report.