(Bloomberg) -- Volkswagen AG’s emissions scandal is stillwidening more than two months after its cheating became public,undercutting the carmaker’s argument that only a few rogueengineers knew of the manipulations.

The U.S. Environmental Protection Agency and the California AirResources Board are now probing Volkswagen, Audi and Porsche modelswith 3.0-liter diesel engines as far back as the 2009 model year,after initially focusing on newer versions. That’s in addition tothe smaller cars that VW admitted in September wererigged to pass emissions tests.

The probe extends the reach of the scandal from VW’sheadquarters in Wolfsburg, Germany, to Audi, the Bavarianluxury-car unit that also builds engines for Porsche. Volkswagenhad initially denied any cheating when first confronted about asmaller number of 3.0-liter Audi-engineered motors earlier thismonth. On Friday, the carmaker conceded that U.S. regulatorsconsidered one feature of the engine-control software to beillegal.