The new Volkswagen CEO Matthias Müller has promised “swift and relentless clarification” of the emissions scandal.

Speaking to more than 20,000 employees at the Wolfsburg plant in Germany, Müller said over the coming days, the customers affected would be informed that the emissions characteristics of their vehicles would be upgraded. Furthermore, VW has set up websites where customers can check whether their vehicles are affected by entering the chassis number.

Müller also said VW will soon be presenting the technical solutions to the responsible authorities — in particular the German Federal Motor Transport Authority (KBA) — for approval.

Meanwhile the EPA is cracking down on car emissions testing. The agency EPA sent a letter to vehicle manufacturers late last month notifying them that the agency is adding to its confirmatory testing additional evaluations designed to look for potential defeat devices.