I came across this Youtube video a while ago and finally got around to watching it all the way through.
The second part, starting at 39:58, is the most interesting as it explains the whole VW diesel scam in some detail. Worth a watch if you are a bit techie.
Note: the original Youtube video was removed but I discovered this replacement, the timings above may not work with the new version.
Probably not the only manufacturer playing games like this but only time will tell.