Apparently, the undisclosed software led to increased emissions of nitrogen oxides (NOx) on a total of 104,000 models equipped with the 3.0-liter diesel engines sold in the United States.
The United States Environmental Protection Agency (EPA) has accused auto manufacturer Fiat Chrysler of violating diesel emissions standards on more than 100,000 trucks and SUVs sold by the company since 2014.
"This is a clear and serious violation of the Clean Air Act", said Cynthia Giles, assistant administrator for EPA. They constitute illegal "defeat devices" only if they reduce the effectiveness of emissions controls outside of testing parameters and are not necessary for safety or engine startup.
"Cummins does not use defeat devices and is committed to meeting emissions standards", according to the statement. 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.
US -listed shares of Fiat Chrysler plunged as much as 18 percent on Thursday in intraday trading.
Today, the Consumers Union, the policy and mobilization arm of Consumer Reports, went on record encouraging regulators to fully investigate Fiat Chrysler.
It's Fiat-Chrysler's turn to face the music for violations of the Clean Air Act.
EPA says diesel-powered versions of the Jeep Grand Cherokee and other vehicles spew excess pollution. It comes amid rising scrutiny by EPA of automaker emissions after Volkswagen AG (VOWG_p.DE) admitted to cheating diesel emissions tests in 580,000 US vehicles.
As was the case with Volkswagen, the EPA is issuing the notice of violation in conjunction with the California Air Resources Board.
Volkswagen agreed to pay $4.3 billion in civil and criminal penalties, in addition to the $15 billion it paid to settle a consumer lawsuit in October.
Volkswagen has also racked up major legal costs stemming from the emissions scandal, as well as seen a dent in sales.
"The American people demand a strong EPA" she said at a conference, which was also attended by U.S. Attorney General Loretta Lynch.
Giles stopped short of calling the software "defeat devices", which Volkswagen used to cheat on diesel emissions tests.
FCA released the following statement in reaction to the EPA's accusation: "FCA US is disappointed that the EPA has chosen to issue a notice of violation with respect to the emissions control technology employed in the company's 2014-16 model year light-duty 3.0-litre diesel engines".