Volkswagen dealers and stockholders are starting to feel the effects of Friday’s charge that many of their 4-cylinder TDI 2.0-liter turbocharged-diesel cars have a software switch that allows them to cheat on emissions test. VW’s stock took a big hit in Monday trading, and dealers are already getting customer calls about the issue. The Environmental Protection Agency and the California Air Resources Board are charging that software in the cars switches engine parameters during testing to lower Nitrogen Oxides to permissible levels. But, when routinely driven, the switch allows up to 40 times NOx limits. Nitrogen Oxides are a leading contributor to smog. While no official recall has been ordered yet, the cars involved include 2009-2015 TDI Volkswagen Jetta, Beetle, Golf and 2012-2015 Volkswagen Passat TDI. The 2009-2015 Audi A3 TDI also uses the same diesel engine. Volkswagen has already apologized for their actions but still could face billions of dollars in fines and lawsuits.