Hi Mike

This is from the Californian website DCA (Department of Consumer Affairs)

http://www.smogcheck.ca.gov/pdf/DieselFlyer_final.3.pdf

The NOX test you refer to is for Petrol vehicles

VAG need to tweak the software to get the emissions down to a level that is acceptable so that they can be sold in the USA. The cheat software is installed just in case a random (or roadside) static test is carried out. But on the open road all bets are off, reverts back to much higher emissions (as the university technician uncovered)

Peter