A senior manager at Fiat Chrysler Automobiles has been charged with conspiring to rig diesel-emissions tests on the automaker’s vehicles, according to a grand jury indictment unsealed on Tuesday. The charges come months after the company agreed to a costly legal settlement of lawsuits over the deception.

Federal prosecutors are charging Emanuele Palma , a manager for diesel drivability and emissions, with wire fraud and violations of the Clean Air Act, among other crimes.

From 2011 to 2017, Mr. Palma and unnamed co-conspirators misled regulators and the public by purposefully calibrating emissions-control systems so that cars would produce lower emissions on regulatory tests than in other situations, according to the indictment, dated Sept. 18.

In a statement, a Fiat Chrysler spokesman said the company would “continue to fully cooperate with the authorities, as we have throughout this issue.” Mr. Palma did not immediately respond to a message requesting comment.