The Volkswagen Group has admitted its cars could "theoretically" have used its manipulation software during European emissions tests - but is trying to establish whether doing so would be illegal.
Asked by Autocar if VW had established whether the manipulation software was employed during European emissions testing, a spokesman said he could only confirm that "the software used in some diesel vehicles can theoretically detect a dynometer set-up and influence the emission strategy."
He added: "So far as we know today only vehicles with diesel engines by code EA189 are affected."
The spokesman also raised the possibility that, even if VW Group cars are found to have employed the software manipulation system in European tests, it may not breach regulations. "It is not certain whether this function can be catagorised as a defeat device under European standards," he said.
Although the regulations clearly state "the use of defeat devices that reduce the effectiveness of emission control systems shall be prohibited", the spokesman's comments suggest VW is investigating not only whether the software activated, but also whether, if it did, it constitues a defeat device under the definitions of the European tests.
Under European regulations, a defeat device is described as "any element of design which senses temperature, vehicle speed, engine speed (RPM), transmission gear, manifold vacuum or any other parameter for the purpose of activating, modulating, delaying or deactivating the operation of any part of the emission control system, that reduces the effectiveness of the emission control system under conditions which may reasonably be expected to be encountered in normal vehicle operation and use."