James Robert Liang, a Volkswagen engineer, pleaded guilty today for his role in a nearly 10-year conspiracy to defraud U.S. regulators and U.S. Volkswagen customers by implementing software specifically designed to cheat U.S. emissions tests in hundreds of thousands of Volkswagen “clean diesel” vehicles, the Justice Department announced today. Liang’s plea agreement provides that he will cooperate with the government in its ongoing investigation.

Liang, 62, of Newbury Park, California, pleaded guilty today to one count of conspiracy to defraud the United States, to commit wire fraud and to violate the Clean Air Act. He was indicted under seal on June 1, 2016, by a federal grand jury, and the indictment was unsealed today. The case has been assigned to U.S. District Judge Sean F. Cox of the Eastern District of Michigan.

According to the plea agreement, from 1983 until May 2008, Liang was an employee of Volkswagen AG (VW), working in its diesel development department in Wolfsburg, Germany. Liang admitted that beginning in about 2006, he and his co-conspirators started to design a new “EA 189” diesel engine for sale in the United States. According to Liang’s admissions, when he and his co-conspirators realized that they could not design a diesel engine that would meet the stricter U.S. emissions standards, they designed and implemented software to recognize whether a vehicle was undergoing standard U.S. emissions testing on a dynamometer or being driven on the road under normal driving conditions (the defeat device), in order to cheat the emissions tests. Liang admitted that he used the defeat device while working on the EA 189 and assisted in making the defeat device work. In May 2008, Liang moved to the United States to assist in the launch of VW’s new “clean diesel” vehicles in the U.S. market, according to the plea agreement. While working at VW’s testing facility in Oxnard, California, he has held the title of Leader of Diesel Competence.

According to the plea agreement, employees of VW and its U.S. subsidiary met with the EPA and the California Air Resources Board (CARB) to seek the certifications required to sell each model year of its vehicles to U.S. customers. Liang admitted that during some of these meetings, which he personally attended, his co-conspirators misrepresented that VW diesel vehicles complied with U.S. emissions standards and hid the existence of the defeat device from U.S. regulators.

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 U.S. emissions standards and complied with the Clean Air Act, according to the plea agreement. 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 and his co-conspirators knew that these representations were false and that VW’s diesel vehicles were not “clean,” he admitted.

In connection with pleading guilty, Liang admitted that he helped his co-conspirators continue to lie to the EPA, CARB and VW customers even after the regulatory agencies started raising questions about the vehicles’ on-road performance following an independent study commissioned by the International Council on Clean Transportation, which showed that the diesel vehicles’ emissions on the road were up to 40 times higher than shown on the dynamometer.

The FBI’s Detroit Office and EPA-CID are investigating the case. Deputy Chief Benjamin D. Singer and Trial Attorney Alison L. Anderson of the Criminal Division’s Fraud Section, Trial Attorney Jennifer L. Blackwell of the Environment and Natural Resources Division, and Criminal Division Chief Mark Chutkow and Economic Crimes Unit Chief John K. Neal of the U.S. Attorney’s Office of the Eastern District of Michigan are prosecuting the case.