Dirty diesels are back in the news as Stellantis is reportedly set to plead guilty in their emissions cheating scandal.

The move has been years in the making as the government contends Stellantis’ predecessor, Fiat Chrysler Automobiles, used “illegal and undisclosed software” on 2014-2016 Ram 1500 and Jeep Grand Cherokee vehicles equipped with the 3.0-liter EcoDiesel V6 engine.

Over two years ago, the government said the software acted as a defeat device and would fully activate emission controls during EPA and California testing, but “reduce or deactivate emission controls” during real world driving. As a result, these models emitted air pollutants at higher rates than allowed.

Also Read: FCA To Pay $800 Million For Its Dirty EcoDiesel Engines

Under the terms of a previous settlement, FCA agreed to recall and repair more than 100,000 diesel-powered vehicles in the United States. The company also agreed to pay a $305 (£239 / €265) million civil penalty and “implement a program to mitigate excess pollution from these vehicles.”

The latest case focuses on the criminal aspect and Reuters is reporting the automaker is hammering out a plea deal with the U.S. Department of Justice. An official announcement could come in a matter of weeks, but sources told the publication it could include penalties of between $250-300 (£182-218 / €215-258) million.

That’s not exactly pocket change and the publication says the automaker was pushing for a deferred prosecution agreement, which would see them charged criminally and agree to an assortment of conditions such as monitoring. This would allow the automaker to avoid pleading guilty as the charges would later be dismissed if the company complied with the conditions in the agreement. However, officials at the Department of Justice reportedly rejected this and demanded the automaker plead guilty.

While the deal could still fall apart, the company has already paid approximately $800 (£582 / €689) million to settle the civil aspect of the EcoDiesel scandal. The automaker also settled a class action lawsuit which saw eligible owners receive a payment of up to $3,075 (£2,237 / €2,650). At the time, FCA said “settlements do not change the company’s position that it did not engage in any deliberate scheme to install defeat devices to cheat emissions tests.”