Volkswagen

A Volkswagen engineer has pleaded guilty in court to his role in the automaker's campaign to trick both the US government and customers in emissions tests over the course of almost 10 years.

On Friday, James Robert Liang admitted he was part of an engineering team which installed so-called "defeat devices" in Volkswagen vehicles. The devices would ensure that US emissions regulations -- as well as those stipulated in other countries -- would be met in lab conditions.

However, while on the road, Volkswagen's "clean diesel" vehicles would produce emissions far beyond what lawmakers now allow in a bid to bring down global pollution levels caused by consumer transport.

The 62-year-old from Newbury Park, California, stood up in a Michigan court and admitted to one count of conspiracy to defraud the United States, to commit wire fraud, and to violate the Clean Air Act through a plea agreement. The engineer was indicted under seal on June 1, 2016, by a federal grand jury, and the indictment was unsealed last week.

According to the plea agreement, from 1983 to May 2008, Liang was employed by the German automaker to work in Volkswagen's diesel development department in Wolfsburg, Germany. In roughly 2006, the engineer and other members of staff began working on the new "EA 189" diesel engine -- but swiftly realized this latest model would not meet US environmental standards.

To circumvent the problem, the engineering team designed the defeat devices and software which would cheat emissions testing.

Liang later moved to the US to help launch Volkswagen's "clean diesel" engines, keeping the defeat devices a secret and insisting that the engines met US pollution standards.

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"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," US prosecutors say.

"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."

Liang could face up to five years of prison for his role in the conspiracy, but by working with US law enforcement, this term may be reduced.

In June, the automaker was ordered to pay $14.7 billion to repair vehicles, compensate customers, and invest in clean energy technology by a US court. Volkswagen is still recalling millions of vehicles worldwide to update software and remove the devices from consumer vehicles, but in the US at least, customers have the option to return their vehicles instead of waiting for repairs.