In another interesting turn of events, the Volkswagen Group (VW) may face additional violations as the Environmental Protection Agency (EPA) recently accused the German automaker of installing “defeat devices” in its Porsche, VW and Audi, subsidiaries.

A “Notice of Violation” on the EPA’s website confirms that the regulator found that 2014 to 2016 VW, Audi and Porsche models are equipped to automatically turn off emissions systems when they are not being tested.

This new finding calls into question whether about 10,000 vehicles, including the 2014 Touareg, 2015 Porsche Cayenne and 2016 Audi, among others are designed to evade emissions tests.

“VW has once again failed its obligation to comply with the law that protects clean air for all Americans,” said Cynthia Giles, assistant administrator for the Office for EPA’s Enforcement and Compliance Assurance. “All companies should be playing by the same rules. EPA, with our state, and federal partners, will continue to investigate these serious matters, to secure the benefits of the Clean Air Act, ensure a level playing field for responsible businesses, and to ensure consumers get the environmental performance they expect.”

The VW scandal has led to the resignation of the company’s Chief Executive Martin Winterkorn and a string of federal investigations, which could cost the German automaker up to $17 billion in fines.

In September, the U.S. government charged that VW had sold more than 500,000 Volkswagen and Audi model cars in the United States with software that was designed to meet emission standards for diesel engines when tested, but pumped out 30 to 40 percent above limit emissions when on the road. In what is known as one of the biggest scandals in the auto industry's history, VW not only admitted to installing "defeat devices" but it also said the amount of cars affected topped 11 million.