The Environmental Protection Agency accused Fiat Chrysler Thursday of using software that enabled some of its diesel trucks to cheat on emissions tests.

The news caused Fiat Chrysler’s stock price to drop more than 13 percent in trading Thursday morning. Fiat Chrysler did not immediately respond to requests for comment.

The vehicles involved were the 2014 to 2016 model year Dodge Ram 1500 pickup trucks and Jeep Grand Cherokees with 3.0-liter diesel engines. The allegations affect roughly 104,000 vehicles, EPA officials said.

The agency’s move is similar to the initial steps it took at the start of the Volkswagen emissions scandal, which eventually lead to about $20 billion in fines and the indictment of seven company executives over the course of the last year and a half. Federal prosecutors announced a settlement with German automaker Volkswagen over its own emissions scandal Wednesday .