Volkswagen's own staff and one of its suppliers warned years ago about software designed to thwart emissions tests, two German newspapers reported on Sunday, as the automaker tries to uncover how long its executives knew about the cheating.
The world's biggest automaker is adding up the cost to its business and reputation of the biggest scandal in its 78-year history, having acknowledged installing software in diesel engines designed to hide their emissions of toxic gases.
Many countries have launched their own investigations after the company was caught cheating on tests in the United States. Volkswagen says the software affected engines in 11 million cars, most of which were sold in Europe, according to Reuters.
The company's internal investigation is likely to focus on how far up the chain of command were executives responsible for the cheating and how long were they aware of it.
The Frankfurter Allgemeine Sonntagszeitung, citing a source on VW's supervisory board, said the board had received an internal report at its meeting on Friday showing VW technicians had warned about illegal emissions practices in 2011. No explanation was given as to why the matter was not addressed then.
Separately, Bild am Sonntag newspaper said VW's internal probe had turned up a letter from parts supplier Bosch written in 2007 that also warned against the possible illegal use of Bosch-supplied software technology. The paper did not cite a source for its report. Volkswagen declined to comment on the details of either newspaper report.
"There are serious investigations underway and the focus is now also on technical solutions" for customers and dealers, a Volkswagen spokesman said. "As soon as we have reliable facts, we will be able to give answers."
A spokesman for Bosch said the company's dealings with VW were confidential.
Bild said Martin Winterkorn, who quit as Volkswagen CEO last week, was demanding his salary for the rest of his contract through the end of next year but the board did not want to pay it. It cited no source.
Winterkorn was paid €16 million last year, the most of any CEO in Germany's blue chip DAX index.
