German carmakers BMW, Volkswagen and Daimler face a fine of billions of euros from EU competition authorities over unauthorized collusion, according to a report in the Friday edition German weekly Der Spiegel.
The fine could be imposed in the coming weeks, the magazine reported.
The European Commission did not comment on the report following a request from dpa.
The carmakers reportedly agreed not to install particulate filters in petrol engines, which would have reduced the emissions of fine dust.
The European Commission initiated an official antitrust investigation in September 2018, but preliminary investigations have been ongoing since 2017.
There is no charge of price fixing, and the opening of the case does not mean that the commission has found any infringement, a Daimler spokeswoman said.
“Daimler is cooperating fully with the authority and has filed a leniency application,” she added.
Volkswagen has submitted a similar application.
The chief witness in the antitrust proceedings can hope for the largest reduction in fines or a possible complete exoneration.
In July 2017, Der Spiegel reported on a cartel of German carmakers that had existed for more than 20 years. Representatives of Volkswagen, BMW and Daimler as well as the VW subsidiaries Audi and Porsche are said to have agreed on vehicles, costs, suppliers and also the cleaning of diesel exhaust gases.
More than 200 employees of the companies are believed to have made agreements in secret working groups since the 1990s, which dealt with the details of the car development.
The official investigations of the European Commission relate only to the issue of emissions.