On Monday morning, shares of Volkswagen Group plummeted more than 20 percent on the Deutsche B rse, Germany's stock exchange in Frankfurt. The loss followed news on Friday morning that the automaker had installed defeat devices on many of its most recent diesel car models.
Defeat device software detects when a car is undergoing emissions testing and burns fuel according to testing standards. When the car is driving under normal operating conditions, however, it will burn fuel without regard to stricter standards, releasing even more pollutants into the air than normal. Some 500,000 Volkswagens and Audis manufactured after 2009 had these defeat devices installed, and they were found to release nitrogen oxide (NOx), which can cause respiratory problems like asthma, into the air at 10 to 40 times the levels permitted by the US Environmental Protection Agency (EPA).
On Sunday, Volkswagen Group said that it would stop selling used cars named by the EPA for having defeat devices installed. Volkswagen also said it would stop selling 2015 and 2016 Volkswagen and Audi models equipped with 4-cylinder turbo diesel engines, which the company has marketed as 'clean diesel,' the New York Times reported.