U.S. regulators accused Fiat Chrysler Automobiles of violating emissions standards in more than 100,000 diesel vehicles in an alleged scheme that bears similarity to the scandal that engulfed Volkswagen Group and cost the German automaker billions of dollars.

The Obama administration’s Environmental Protection Agency said Thursday that Fiat Chrysler installed software on about 104,000 pickup trucks and sport-utility vehicles to evade emissions standards.

The allegations cover the 2014, 2015 and 2016 Jeep Grand Cherokee and light-duty Ram 1500 trucks with 3-liter diesel engines.

The EPA said the automaker installed eight different undisclosed software programs on the vehicles that collectively caused them to spew harmful nitrous oxide emissions, which can exacerbate breathing conditions.

“This is a clear and serious violation of the Clean Air Act,” Cynthia Giles, assistant administrator for EPA’s Office of Enforcement and Compliance Assurance, told reporters. “There is no doubt they are contributing to illegal pollution.”

Fiat Chrysler (FCAU)  shares traded in New York plunged 14.2% at 11:41 a.m. to $9.52.

The EPA has the authority to fine automakers up to $44,539 per vehicle for the worst violations of the Clean Air Act, meaning the scandal could theoretically cost the Italian-American more than $4.6 billion in civil penalties. The agency threatened possible fines on Thursday if it determines that the software installed on the vehicles qualify as illegal “defeat devices” under U.S. laws.

But it’s possible the incoming Trump administration won’t continue the Obama administration’s investigation or won’t crack down as aggressively.

Fiat Chrysler said it was “disappointed” by the notice of violation and plans to plead its case to the Trump administration, saying that it had offered to develop software fixes to “further improve emissions performance” because it wants to “resolve this matter fairly and equitably.”

The vehicles were programmed with software that violated standards and was not disclosed to the EPA, Giles said. In lab testing, the vehicles met standards but at high speeds and in extended driving they violate regulations, Giles said.

“That means that the vehicles were sold illegally,” she said.

The agency said it discovered the alleged violations after expanding its testing of on-road vehicle performance following the Volkswagen scandal.

Volkswagen admitted to cheating emissions laws on more than half a million vehicles and has since agreed to criminal and civil settlements totaling nearly $22 billion. Six VW executives were charged Wednesday with allegedly weaving a conspiracy to dodge regulations while the company pled guilty to similar charges on a corporate level.

In Volkswagen’s case, vehicles were spewing NOx emissions at rates of up to 40 times the U.S. standard. Giles declined to provide a comparable assessment for Fiat Chrysler.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.