Loading ...VW’S DEFEAT DEVICE – The software switched on when the automobiles were being tested for compliance with EPA standards, turning off during normal driving to allow maximum engine performance. The algorithm used information about how the car was being steered, how long the engine ran and atmospheric pressure to “precisely track” the conditions that corresponded to a federal emissions test, according to the EPA.
http://www.reuters.com/article/2015/09/21/us-usa-volkswagen-diesel-factbox-idUSKCN0RL2AB20150921