MUNICH (Reuters) - German prosecutors said on Thursday they had launched another probe into Robert Bosch GmbH over its suspected involvement in emissions test cheating - this time in relation to its work with Volkswagen's <VOWG_p.DE> premium carmaker Audi.
Audi developed the V6 diesel engine that was fitted with illicit emissions control equipment and used in the United States in over 80,000 VW, Audi and Porsche models with 3.0 liter engines.
Prosecutors in Stuttgart, where Bosch is based, said they started at the end of December to investigate unidentified staff at Bosch, which makes emission-control devices and software, confirming a report by Wirtschaftswoche earlier on Thursday.
Bosch is fully cooperating with authorities, a spokesman said, without being more specific.
The Stuttgart prosecutors launched an investigation over Bosch's emissions dealings with Volkswagen (VW) in 2015 when VW's diesel test-cheating scandal in the United States broke, and in 2017 in relation to alleged emissions irregularities at Daimler.
On Wednesday, Bosch said it took "very seriously" allegations of diesel software manipulation by Ford Motor Co raised by a U.S. law firm which named the components maker as a defendant in a lawsuit.
(Reporting by Irene Preisinger; Writing by Andreas Cremer; Editing by Mark Potter)