Originally Posted By: tfabris
I think that saying "defeat device" is due to a misunderstanding of the way engine management computers work in modern automobiles.

Aha, I found why the term "defeat device" is being used. This is a legal term that hasn't changed to match modern times, but has had it's definition updated.

Originally Posted By: EPA
The software produced by Volkswagen is a “defeat device,” as defined by the Clean Air Act.