Sort of and sort of not right? So VW came right out and said &quot;The difference is caused by defeat device code programmed into the computer.&quot; Great simple answer. None of these people have offered up a theory of why things are different. It <i>could</i> be defeat devices, or it could be something else, they just don&#x27;t know.<p>So step two of this process is figure out all the ways in which actual driving differs from lab testing. And when you&#x27;ve eliminated all other explanations, start looking for defeat devices or their equivalents.<p>I&#x27;m guessing one or more of these companies will end up admitting, after looking into it, that their car control software runs differently if it detects the car is being tested.