Comment by bri3d

While I certainly don't buy the "pesky engineers" argument, it's actually somewhat plausible Porsche didn't know about the cheating (beyond what everyone knew, which was that the stated mileage and emissions were virtually impossible to achieve by any known mechanism). Since they dropped a VW manufactured engine (3.0 TDI) into a shared VW chassis (Touraeg) and built the Cayenne around that, there's a good chance the engine and engine management were treated as a black box and simply integrated at face value.