US environmental regulators on Tuesday filed a lawsuit against automaker Fiat Chrysler, accusing the company of installing devices on its trucks that hid harmful emissions during testing.
The company kept the software's existence from regulators during the certification process for 104,000 3.0-liter light-duty diesel vehicles, according to the Environmental Protection Agency, which announced the charges filed in federal court in Michigan.
The latest legal action against a carmaker comes the same month that Germany's Volkswagen closed the last major US chapter of its own "dieselgate" saga, which has cost that company $22 billion in settlements and compensation in North America since 2015.
The EPA first made the emissions cheating charge against Fiat Chrysler in January, involving the Ram 1500 and Jeep Grand Cherokees from the 2014 to 2016 model years.
The Italian-American automaker said Tuesday it was "disappointed" by the lawsuit and "intends to defend itself vigorously, particularly against any claims that the Company engaged in any deliberate scheme to install defeat devices to cheat US emissions tests."
Fiat Chrysler said in a statement it had been working with the EPA on the issue, and already developed updated emissions software it hoped would address the concerns of the EPA and California regulators.
The company already is facing class-action lawsuits over the alleged emissions cheating.
- A better deal from Trump? -
In reacting to the EPA's allegations in January, Fiat Chrysler described the matter as a simply a problem with the calibration of the emissions software, and CEO Sergio Marchionne angrily dismissed allegations of illegal conduct by the company.
At the time, the company said it would work with the incoming administration of President Donald Trump to resolve the matter.
Trump and his EPA administrator have opposed environmental regulation, which Trump has said destroys "millions" of jobs, and the administration is considering loosening auto emissions standards at the request of the industry.
But the filing of the lawsuit showed the company so far had failed to reach a more amicable resolution despite the new occupant in the White House.
According to the complaint, Fiat Chrysler failed to reveal the existence of at least eight auxiliary emissions control devices that, when used separately or together, had the effect of "bypassing, defeating, or rendering inoperative" the vehicles' pollution control systems.
The lawsuit concerns far fewer vehicles than the VW scandal, which involved 11 million cars sold worldwide. But the complaint is similar in that the devices allowed vehicles to emit more than the permissible levels of nitrogen oxides, which contribute to smog and soot, according to the EPA.
That pollution causes lung and heart conditions that lead to premature deaths, especially in children and the elderly, according to the EPA.
The lawsuit, which was filed by the Justice Department, seeks fines and an order prohibiting Fiat Chrysler from importing or selling any more non-compliant vehicles or parts and requiring the company to fix deficient cars.
But talks continuing with Fiat to reach a settlement, according to the EPA.
"The nature and timing of any resolution of this issue are uncertain," the agency said.
Following Tuesday's news, shares in Fiat Chrysler fell more than four percent on the New York Stock Exchange.