Porsche could be forced by the German government to pay a sizeable fine after admitting type-approval data relating to the outgoing 991-series 911 was incorrect.
The fuel-consumption and emission data submitted to the German Transport Ministry prior to the granting of type approval for unspecified 911 models in 2016 and 2017 included incorrect values due to miscalculations in their drag coefficient.
According to a report by the online edition of German magazine Der Spiegel, Porsche self-reported the error to German authorities and also is set to inform U.S. authorities.
Der Spiegel reported that laboratory tests carried out on the recently superseded 911 failed to factor in the proper drag coefficient, which led to figures that do not represent real-world fuel consumption and emissions.
Fuel consumption and emissions values gained on a rolling road are much lower than those in the real world owing to a lack of wind resistance. The error means the affected 911 models use more fuel and emit more emissions than noted in their type approval.
Porsche Chairman Oliver Blume says he has informed the Transport Ministry of the false data and Porsche engineers reportedly are working with German government authorities to determine the extent of the miscalculation.
Under German law, automakers can be fined if fuel consumption and emissions vary by more than 10% from their claimed values, and customers also could claim compensation. It is not yet known how much variation there is between the figures Porsche recorded, or how many cars are affected.
Porsche officials in Stuttgart, Germany, have not yet replied to a WardsAuto request for comment.