WASHINGTON — Ford Motor Co., already reeling from business setbacks, recalled 1.2 million trucks, sport utility vehicles and vans Thursday amid concerns about potential engine fires.

Ford said the recall was tied to the speed control deactivation switch system, which could corrode over time, overheat and ignite. It builds upon one of the largest recalls in U.S. history.

The recall involves vehicles fueled by gasoline or natural gas and equipped with speed control, including the 1994-2002 F-250, F-350, F-450 and F-550 F-Super Duty trucks, 2000-2002 Excursion SUVs, 1994-1996 Econoline vans and 1996-2002 E-450 vans, and 1998 Explorers and Mountaineers. The recall does not involve similar vehicles fueled by diesel.

Last September, Ford recalled 3.8 million pickups and SUVs from the 1994-2002 model years, including the top-selling F-150 pickup, because of the concerns over engine fires. It was the fifth-largest auto recall in U.S. history.

In January 2005, the company recalled nearly 800,000 pickups and SUVs from the 2000 model year because of similar issues.

The National Highway Traffic Safety Administration said Thursday it closed a nearly two-year investigation into the cause of the fires. The agency has received 1,472 complaints connected to the problems, including 65 reports of fires.

NHTSA said there have been no confirmed deaths or injuries, but lawsuits have been filed over three deaths in Iowa, Georgia and Arkansas, allegedly connected to vehicle fires.

Owners of the newly recalled vehicles will receive notices in the mail in a week and dealers will install a fused wiring harness. Customers can contact Ford at 1-888-222-2751.