Germany's car authority KBA has started a probe against Porsche, suspecting incorrect fuel consumption data for gasoline-powered cars, news portal Business Insider reported on Thursday.
Porsche said it had made a voluntary notification to the authority as "a pre-cautionary measure" a year ago, regarding conformity issues with individual vehicles.
"The current procedure has already been able to find no conformity deviations in the large majority of vehicles," a Porsche spokesperson said in an emailed statement.
The number of vehicles affected was "far less" than 1 percent of the Porsche fleet, the spokesperson said, adding no decision had yet been reached and that proceeding were at an early stage.
KBA was not immediately available for comment.