The Department of Justice sued Fiat-Chrysler on Tuesday for violating the Clean Air Act by using software on diesel vehicles that cheated emissions tests. These "defeat devices" were installed in more than 100,000 Ram trucks and Jeep Grand Cherokee vehicles from 2014 to 2016. "This results in cars that meet emission standards in the laboratory and during standard EPA testing," the agency said in a statement, "but during certain normal on-road driving emit oxides of nitrogen that are much higher than the EPA-compliant level." The company said it denied the government's claim it engaged in a "deliberate scheme" to mislead regulators. Defeat devices were used by Volkswagen to make diesel engines appear compliant with U.S. emissions rules when they were not. VW agreed to pay a $17 billion civil settlement to the U.S. last year and another $2.8 billion in a criminal fine.