On Sat, 19 Sep 2015 00:19:10 +0000, Ewald Böhm wrote:

My question is HOW did the car *know* it was being *tested* for emissions?

The best answer to the question seems to be here, as noted by Sofa Slug:

http://www.rocketnews.com/2015/09/did-volkswagen-cheat/
http://www.latimes.com/opinion/edito...919-story.html

"How can the program tell the difference? By noting the position of the
steering wheel, variations in speed and other data that suggest no one
is driving the car, and thus it is likely being tested."

Apparently VW lied at first, & apparently they can no longer sell the cars:

"The cheating came to light when the California Air Resources Board and
the EPA pressed Volkswagen for an explanation for disparities found between
lab tests and road tests of its vehicle emissions. The agencies didn't
find the technical reasons offered by VW to be convincing and said they
would not issue certificates allowing 2016 models to be sold until the
automaker offered an adequate explanation. "Only then did VW admit it
had designed and installed a defeat device in these vehicles," the EPA
said. VW said it was cooperating with the investigation but otherwise
had no comment."

It's interesting that VW didn't fess up until they were forced to.