Toyota received complaints from customers in Europe about sticking accelerator pedals as early as December 2008 and started installing redesigned pedals on new vehicles there last August. Months later, in January, similar concerns in the United States led to a pedal recall of 2.3 million vehicles. The European cars have now been recalled, too.

In a Congressional committee meeting on Jan. 27, Toyota officials said they first learned of this problem through reports of sticking pedals in vehicles in England and Ireland in the spring of 2009. But Toyota later acknowledged it had received reports there as early as December 2008.

Three years ago, it recalled 2007 and 2008 Toyota Camrys and Lexus ES 350s because the accelerator could stick under floor mats, a precursor to a much bigger recall last fall.

And in early 1996, Toyota engineers discovered that a crucial steering mechanism could fracture on the Hilux Surf, which was sold as the 4Runner in the United States. Toyota started installing a stronger version on new models.

Yet it took Toyota eight more years to start recalling Hilux Surfs and 4Runners built before the 1996 design change, after an accident involving an out-of-control Hilux Surf prompted a police investigation. Toyota received a rebuke from the Japanese government and was ordered to overhaul its recall system.

Many automakers address problems discreetly when feasible, hoping to avoid an uncomfortable spotlight.

But Toyota, a company that built its reputation with meticulous attention to quality, is now facing a credibility crisis as little-known problems are surfacing with many of its models.

Most recently, Toyota acknowledged it had identified a flaw in the antilock braking systems of its Prius hybrids and altered the system for models built since January. Facing new investigations, Toyota said it was considering a recall. Late Friday it began telling dealers that it would announce a fix early this week.

Toyota officials, when asked about their handling of previous safety issues, responded largely with comments about how they would handle the matter now and in the future.

“The company is prepared to cooperate fully and sincerely, and we are doing our utmost to deal with the matter in a way that brings safety and peace of mind to our customers,” the company’s chief executive, Akio Toyoda, said Friday at a news conference.

“We acknowledge that we could have communicated better as a company,” said James Wiseman, a spokesman for Toyota’s United States division. “However, we have taken significant steps to address these issues.”

Toyota’s handling of safety problems contrasts with steps Toyota took 30 years ago, when it was building its American operations.

Faced with engine and transmission problems on early Camrys, the company’s engineers addressed them, and by the mid-1980s, the Camry’s quality was considered on par with that of the Honda Accord.

After defects showed up on the first Lexuses in 1989, Toyota put together a team to solve them quickly. In many instances, the company went to customers’ homes to collect the cars.

Years later, many consumers started seeing evidence of a more reactive and defensive approach from the company.

In 2002, for example, Toyota faced thousands of complaints from customers who said their cars’ engines could become clogged with oil sludge.

Toyota initially faulted drivers, saying the problem was a result of infrequent oil changes. It agreed to extend warranties to eight years on 3.3 million 1997-to-2002 models. Customers then complained that Toyota made it too difficult to file claims, and the company was soon defending itself from a class-action suit.

Now the company is facing more public accusations of being slow to respond.

The transportation secretary, Ray LaHood, decided to confront Toyota late last year when it did not announce a recall for sticking pedals, although it had recalled millions of cars because their floor mats could interfere with the accelerator.

“Maybe they were a little ‘safety deaf’ in their North American office,” Mr. LaHood told The Associated Press last week.

Japan’s Transport Ministry appeared to be a step ahead of Toyota last week. It ordered the company to investigate problems on the 2010 Prius hybrid that could cause its brakes to be unresponsive when driving slowly on bumpy or icy roads.

Toyota then said it had corrected the problem on cars built since mid-January. But it now faces a decision on whether to recall more than 300,000 cars sold since the newest version of the Prius was introduced last spring.

The most severe criticism has been over Toyota’s handling of the pedal problem.

The company did not recall cars with sticky pedals in Europe, after it made a design change for new cars, because it considered the problem a “customer satisfaction” issue rather than a defect. None of the 26 complaints it received involved cars that had been in accidents, Toyota officials said.

It introduced the design change for new cars being built in Europe last summer, before sticky pedal problems came to a head in the United States.

Only after Toyota announced a recall in the United States did it then extend the recall to 1.8 million European vehicles as well.

In a filing with the National Highway Traffic Safety Administration, Toyota said it had not realized until October that the pedals in cars made in the United States used the same material as those in Europe — even though both are supplied by the same parts maker, CTS of Elkhart, Ind.

Although it made the change on European models last summer, Toyota initially told American authorities it was unaware of any problems with the CTS-made pedals. Instead, Toyota said it believed gas pedals were becoming trapped in floor mats, the subject of an advisory to consumers that was later followed by a recall.

Toyota had “not been able to single out or verify any other cause” for the unintended acceleration, the company said when the floor-mat recall was made.

Analysts questioned Toyota’s explanation.

“There is no way that Toyota in America or Japan would not have known about a replacement taking place in Europe,” said Tadashi Nishioka, an auto industry expert at the University of Hyogo in Japan. “At Toyota, all information flows to headquarters. It’s that kind of company.”

Colin Hensley, the general manager of corporate affairs at Toyota Motor Europe, said the change would eventually have been brought to cars in the United States under Toyota’s practice of sharing new production methods among its plants.

Shinichi Sasaki, the Toyota executive in charge of quality, added last week: “We did realize that it was not good that pedals were not returning to their proper positions, but we took some time to consider whether we needed to take market action.”

When American regulators visited Japan, they “directed us to think of things from a customer’s perspective,” Mr. Sasaki added. “We took this seriously and made the decision to recall the cars.”

Last week, Toyota dealers began replacing pedals on millions of cars. Factories will start installing them in new cars this week.