Volkswagen has confirmed that its 3.0-liter turbocharged diesel V6 engine also cheated on EPA diesel emissions tests.

The engine is used in various Audi, Porsche and Volkswagen models including the Cayenne SUV which is currently under a stop-sale order. Originally Volkswagen denied the charges by the EPA, but the German automaker has now told regulators that 75,000 vehicles using the 3.0-liter turbo-diesel V6 engine are improperly fitted with auxiliary emissions controls. This is in addition to the 482,000 vehicles equipped with the Volkswagen Group’s 2.0-liter diesel four-cylinder engine that were outed by the EPA in September.

It’s worth noting that automakers are allowed to use auxiliary emissions controls so long as they are revealed and detailed during the testing process. Volkswagen however, did not reveal the use of such auxiliary emissions controls and failed to properly notify regulators. Although how the auxiliary emissions controls function hasn’t been detailed, it is believed that the technology is designed to warm parts of the exhaust system to reduce emissions, since components like the catalytic converter perform better when warm.

It is still unclear how Volkswagen plans on fixing all the affected diesel engines.

This article originally appeared at AutoGuide.com