The German car maker admitted last week that it used special software to fool US emissions tests for its diesel vehicles. Some 11 million VW diesel cars built since 2008 are affected by the scandal.
German weekly Bild am Sonntag reported that VW’s internal investigation has found a 2007 letter from parts supplier Bosch warning Volkswagen not to use the software during regular operation.
Separately, the Frankfurter Allgemeine Sonntagszeitung reported a Volkswagen technician raised concerns about illegal practices in connection with emissions levels in 2011. The weekly also cited VW’s internal investigators.
A spokesman for Volkswagen declined to comment on the reports, saying that as a matter of principle the company would not respond to what he called “rumours and speculation”.
In an email, Andreas Lampersbach said: “Volkswagen is working with all its strength to conduct a thorough and merciless investigation of this matter.”
VW would hold those responsible for rigging the emissions test to account and discuss technical solutions for the problem with authorities, he said, citing a statement by the company’s supervisory board.
“Afterwards we will provide a timetable to modify the vehicles of affected customers. This will take several weeks.”
Italian media reported yestersday that Volkswagen’s Italian unit has sent a letter to all of its dealers to stop selling cars that have the affected diesel engine. According to the news agency ANSA, the letter said it was “a precautionary measure”.
The daily Corriere della Sera said the move would affect 40,000 vehicles and deal a blow to car dealers, a sector that has been losing money for ten years and finally seemed to be emerging from the crisis.
Legal experts in the US said Volkswagen is likely to face significant legal problems, including potential criminal charges.
The US Environmental Protection Agency has accused VW of installing sophisticated stealth software that enabled “clean diesel” versions of its Passat, Jetta, Golf and Beetle models to detect when they were being tested and emit less-polluting exhaust fumes than in real-world driving conditions.
The agency said the “defeat devices” allowed those models to belch up to 40 times the allowed amounts of harmful fumes in order to improve driving performance.
The country’s Justice Department has said it is “working closely” in conjunction with EPA investigators.
“If there is sufficient evidence to show that Volkswagen intentionally programmed its vehicles to override the emission control devices, the company and any individuals involved could face criminal charges under the Clean Air Act, and for conspiracy, fraud and false statements,” said David M Uhlmann, a former chief of the Justice Department’s Environmental Crimes Section who is now a law professor at the University of Michigan.
He described criminal charges “almost certain.”
But Mr Uhlmann cautioned that hauling the executives concerned involved into a US courtroom could be challenging because much of the conduct at issue probably occurred overseas.