The emission-scandal plot continues to thicken for Volkswagen and U.S. regulators. Nearly a month after the Environmental Protection Agency and California Air Resources Board accused the carmaker of including “defeat devices” in an additional 10,000 previously unreported vehicles, investigators for the agency say the number of cars is significantly higher. 

The EPA announced [PDF] Friday that during a meeting between the parties on Thursday, VW and Audi officials acknowledged that a November notice of violation extends to all 3.0-liter diesel engine vehicles from model years 2009 to 2016.

Regulators revealed on Nov. 2 that they had identified additional Clean Air Act violations in approximately 10,000 model year 2015-2016 VW Touareg, the 2014-2016 Porsche Cayenne, and the 2015-2016 Audi A6 Quattro, A7 Quattro, A8, A8L, and Q5.

The “sophisticated software algorithm” in the vehicles is programmed to detect when the car is undergoing official emissions testing, and to only turn on full emissions control systems – the temperature conditioning mode – during that testing.

The EPA and CARB said on Friday that they will “continue to investigate and will take all appropriate action.”

Shortly after the Nov. 2 violation order was announced, VW denied the allegations.

“It is a permissible software. What’s at issue here is clear: Does the U.S. want competition in the American market or not?” the spokesperson said at the time, noting the company would continue to sell the vehicles.

Days later, the company seemingly did a 180, issuing a stop-sale of new and certified pre-owned 3.0 liter, 6-cylinder models covered by the notice of violation.

The move marked the company’s second stop-sale since September when regulators accused VW of installing the so-called defeat devices on about 482,000 diesel vehicles since 2008.

Days later, the German carmaker admitted that nearly 11 million vehicles worldwide contained a “sophisticated software algorithm” programmed to detect when the car is undergoing official emissions testing, and to only turn on full emissions control systems – the temperature conditioning mode – during that testing.

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