The United Sates Environmental Agency (EPA) has issued a notice of violation NOV to Volkswagen AG, Audi AG, Porsche AG, Volkswagen Group of America, Inc., and Porsche Cars North America, Inc. today. This is due to over 10,000 vehicles on the road with diesel engines designed to give out false emission readings when tested. The false readings camouflage the actual level of pollutions emitted by the cars.

According to the text of the NOV, certain six- cylinder (3.0 liter) diesel vehicles are alleged to also employ software that circumvents EPA emissions standards.

The software is a “defeat device,” as defined by the Clean Air Act. California separately issued an In-Use Compliance letter to Volkswagen, Audi, and Porsche. 

VW is already facing a fine of as much as $18 billion from U.S. regulators for violating the Clean Air Act, because each car found in violation can be subject to a $37,500 fine.

The additional fine from 10,000 additional cars is not that much, when put into perspective – about $375 million more than original estimates. But the cost of satisfying the car owners could be significantly more since these are higher priced vehicles.

Both the EPA and the California Air Resources Board are investigating Volkswagen’s alleged actions involving both sets of vehicle

Affected models include the 2014 VW Touareg, the 2015 Porsche Cayenne, as well as the 2016 Audi A6 Quattro, A7 Quattro, A8, A8L, and Q5.