When on the road, however, Volkswagen diesel vehicles would produce much higher emissions than are allowed.
According to the engineer, he worked on the new "EA 189 diesel engine". However, later on he realised that the engine could in no way meet the US environmental standards.
To fight the problem, the engineers designed a "defeat device" and "defeat software" that was engaged, when testing for emissions.
US prosecutors say that "as part of the certification process for each new model year, including model years 2009 through 2016, the co-conspirators continued to falsely and fraudulently certify to EPA and CARB that VW diesel vehicles met US emissions standards and complied with the Clean Air Act"
"Liang admitted that during this time, he and his co-conspirators knew that VW marketed its diesel vehicles to the U.S. public as "clean diesel" and environmentally-friendly, and promoted the increased fuel economy."
The engineer can face up to 5 years in prison for conspiring, however, by working with the US governent, he can potentionally reduce his sentence.