Porsche has informed Germany's automotive watchdog KBA, the Stuttgart prosecutor's office, as well as U.S. authorities of suspected illegal changes to hardware and software that could affect exhaust systems and engine components, the paper said.
"Porsche is regularly and continuously reviewing technical and regulatory aspects of its vehicles," a Porsche spokesman said. "As part of such internal examinations Porsche has identified issues and has, just like in the past, proactively informed authorities."
The spokesman said that the issues relate to vehicles developed several years ago, adding that there were no indications that current production was affected. The carmaker is working closely with authorities, he said.
BamS, not citing where it obtained the information, said that engines developed between 2008 and 2013 were the subject of the investigation, including those of the Panamera and 911 models.
The paper also said that apart from discussions with employees, meeting protocols and hundreds of thousands of emails were being examined in search of evidence, adding KBA has launched an official investigation.
(Reporting by Christoph Steitz; Editing by Aurora Ellis)