An owner of a Mercedes BlueTEC diesel car filed a class-action lawsuit in the United States, accusing the carmaker of knowingly programming its Clean Diesel vehicles to emit illegally high levels of nitrogen oxide, according to law firm Hagens Berman.
Shares in Mercedes maker Daimler were down 3 percent Friday after news of the class-action lawsuit, filed by Hagens Berman, which also has a lead role in class-action suits against Volkswagen.
Diesel car makers have been in the spotlight since Volkswagen admitted in September it had rigged U.S. diesel emissions tests, and that up to around 11 million vehicles worldwide could have illegal software installed.
The U.S. Justice Department is suing the company for up to $46 billion for alleged violations of environmental law.
Daimler has repeatedly denied that it has rigged tests as well, and said on Friday it saw the suit, filed in the U.S. District Court for the District of New Jersey on Thursday, as unfounded.
A spokesman said the carmaker would examine the levels and defend itself against the suit.
Hagens Berman said in a statement that on-road testing had shown Mercedes's Clean Diesel cars produced average on-road NOx emissions that were 19 times above the U.S. standard, with some instantaneous readings as high as 65 times more than the U.S. limit.