The Ford Motor Company recalled close to four million pickup and sport utility vehicles

The Ford Motor Company recalled close to four million pickup trucks and sport utility vehicles on Wednesday, saying that a leak-prone cruise control system could ignite fires.

The recall, the fifth-largest by an automaker in United States history, involves some of Ford's most popular trucks and S.U.V.'s, including the nation's top-selling vehicle, the F-150 pickup. Ford Expeditions, Broncos and Lincoln Navigators are also included in the recall, which affects many models from as far back as 1994 up to 2002. Ford said owners of affected vehicles would be notified by mail immediately.

Separately Wednesday, Toyota recalled nearly a million older pickups and S.U.V.'s, citing a malfunctioning steering mechanism. At Ford, the system in question is the focus of a continuing federal safety inquiry and numerous lawsuits now pending against Ford. In most cases, victims assert that fires in their Ford vehicles caused property damage. But in a handful of lawsuits, plaintiffs are accusing the fires of causing deaths.

For the first time on Wednesday, Ford said it had reason to believe the cruise control system was malfunctioning and in some cases causing fires. But the company said that it had found no sign that the fires were responsible for any deaths. "Ford has no evidence indicating that any of these actually relate to the switch," it said in a letter to the National Highway Traffic Safety Administration. Ford said it believed that brake fluid may leak from the switch that deactivates the cruise control once the driver steps on the brake pedal. That fluid can drip down to the cruise control's electrical component, cause corrosion and ignite a fire, the company said, reported The New York Times.