In a report published in the German Newspaper, Bild am Sonntag, engineers from the Volkswagen Group have laid the blame for the emissions scandal, on former VW Group CEO Martin Winterkorn.
At the 2012 Geneva Motor Show, Winterkorn set a target of reducing VW's emissions levels by 30% by 2015. In a bid to please their CEO, VW's engineers resorted to cheating to bring emission levels down.
German media are reporting that in addition to the cheat devices, they also rigged the tests to ensure better results. Rigging methods included inflating tires to higher pressures as well as using skinnier tires than the ones usually provided to reduce rolling resistance. Another method used was to add motor oil to the diesel fuel.