NEW YORK — Toyota is recalling nearly half a million cars, most of them large sedans sold in the U.S., for problems that can cause the steering wheel to lock up. It's the latest indication that the automaker still is struggling with vehicle problems even as it works to overhaul quality control.

NEW YORK — Toyota is recalling nearly half a million cars, most of them large sedans sold in the U.S., for problems that can cause the steering wheel to lock up. It's the latest indication that the automaker still is struggling with vehicle problems even as it works to overhaul quality control.

The recall, announced Thursday, affects 412,000 vehicles in the U.S. — 373,000 Avalon sedans and 39,000 Lexus LX 470 SUVs. The recall is Toyota's largest since announcing it would fix 600,000 Sienna minivans over rusting spare tire holders in April.

Toyota has been embroiled in its recall crisis since October, when it announced a recall of 5.3 million cars and pickups to fix floor mats that can trap pedals and cause unintended acceleration. A number of recalls have followed, from sticky gas pedals to braking problems with the Prius hybrid to rusting frames in the Tacoma pickup.

Thursday's announcement brings the size of Toyota's recalls to about 9.5 million cars and trucks in the U.S. since October.

"I don't think it's going to end anytime quickly or easily," said George Magliano, auto analyst with the consulting firm IHS-Global Insight, of the company's recalls. "Toyota had this big run of growth. The more they grew volume and market share, the more this (quality) system started to develop cracks."

The Avalons recalled in the U.S. range from the 2000 model year through 2004 and have improper casting of the steering lock bar — the component that locks the steering wheel when the vehicle is shut off — that can cause a crack to form on the surface.

Over time, the crack can expand, which can cause the steering wheel to become difficult to unlock when stationary. In some circumstances, the problem can cause the steering wheel to lock up during driving, Toyota said.

Three unconfirmed accidents with no injuries have been reported because of the problem, Toyota said. It will fix the Avalon steering problem by replacing a part called the steering column bracket, which houses the lock bar.

For the Lexus LX 470, Toyota is recalling the 2003-2007 model years to fix a different steering shaft problem, which could cause loss of steering control. No accidents have been reported from the problem, the company said.