Jaguar North America is recalling 45,000 vehicles that may not meet federal clean air emission standards due to a malfunction of the exhaust recirculation valve.

The recall covers 1995-1997 models of the XJ6, XJR and the Van den Plas and the 1995-1996 models of the Jaguar XJS, the Environmental Protection Agency said Friday.

EPA requested the recall after testing officials found the malfunction at a lab in Ann Arbor, Mich. The agency said the fault could increase emissions of nitrogen oxides, major contributors to ground-level smog, which can trigger asthma and other respiratory problems.

The recirculation valve is used in cars to lower the temperature of engine combustion to prevent nitrogen oxide formation.

EPA said the malfunctioning valve also may cause the car to run roughly.

Jaguar has agreed to install a new valve and a new computer chip to control it, the EPA said. The manufacturer began sending letters notifying owners of the recall on Aug. 27.

The letter tells owners their vehicles will be repaired without charge at Jaguar dealerships. The company's customer relations center can be reached at 1-800-452-4827.