The company revised its emissions software before seeking certification for the 2017 Jeep Grand Cherokee and Ram 1500 diesel vehicles.

a Researchers from the University of California, San Diego and the University of Ruhr in Bochum, Germany have reportedly found evidence of an emissions 'defeat device' in the Fiat 500X.

The group analyzed the vehicle's computer systems and found a provision that reduces emissions controls after the engine has been running for 26 minutes, just a few minutes after a standard emissions test would be complete, according to a New York Times report.

The findings appear to corroborate accusations from European regulators and the US Environmental Protection Agency and California Air Resources Board.

Separate reports suggest FCA is involved in settlement negotiations with US regulators. It is unclear if the independent research will be considered by enforcement authorities.

"In the case of any litigation, FCA US will defend itself vigorously, particularly against any claims that the company deliberately installed defeat devices to cheat US emissions tests," the company recently said in a statement.

As the legal showdown inches forward, the automaker updated its emissions software calibrations for the 2017-model-year diesel Jeep Grand Cherokee and Ram 1500 before seeking EPA and CARB certification.

"FCA US believes this will address the agencies' concerns regarding the emissions software calibrations in those vehicles," the company says. "FCA US also believes that these actions should help facilitate a prompt resolution to ongoing discussions with the Environment and Natural Resources Division of the U.S. Department of Justice and other governmental agencies."

The revised software will also be available for the 2014-2016 model years. FCA says it "does not anticipate" any negative impact on performance or fuel efficiency.