[Tervuren]

Originally Posted by 1990C4S

1. is not the answer, otherwise a Scangauge or OBDII reader would put the car into test mode, which apparently does not happen.

Wheel speed on a dyno is reportedly one component (front wheels turning, rear wheels stationary). But if they used this method Europe it would fail, as they sell AWD diesels there.

There is a steering angle sensor built into the ZF electric power steering box, so the car knows exactly what the steering angle is, and I would guess the car is not occupied for an EPA test.

The speeds use by the EPA are very closely controlled, with 0.1 mph I believe, so a few seconds at either the low or the high speed would be another factor. http://www3.epa.gov/nvfel/methods/la92dds.txt



And yes, I believe the atmospheric pressure is controlled.

They didn't cheat European emissions regulations, the USA has its set of "extras".