Originally Posted by oldford

This is a bit more serious than exaggerating power figures or fuel usage.
But even exaggerating fuel usage figures can cost you hunderd's of million dollars in the US as Hyundai and Kia have found out.

What they basically did was use a software routine that could detect whether the car was undergoing an emission test or was driving on the highway.
When the emission test was detected the car was clean and complied with (strict) US rules. Otherwise they did not comply and produced 10 tot 40 times the amount of NOx that was allowed.
See: http://www.washingtonpost.com/news/e...tion-controls/