The German Transport ministry has ordered a probe to find out whether Porsche used a cheat device in the Cayenne V6 diesel models.
The specific V6 diesel unit is sourced from Audi, which is also under an official investigation on suspicion of irregular emissions from engines in models like the A8, A7, Q7 and Q5.
A spokesman for the German Transport ministry has confirmed the investigation on Porsche, according to Reuters.
German magazine Der Spiegel reported that the V6 diesel version of the Porsche Cayenne had much higher emissions than the legal limit in a test conducted by TUV Nord and under normal driving conditions.
“Emissions in this test were higher than the limits for this type of car,” the magazine quoted the head of testing at TUV Nord, Helge Schmidt, as saying. “With these values the car would not have been approved by the authorities,” Schmidt said.
Porsche responded saying that these tests “are not comprehensible” and noted that emissions depend on conditions such as engine load, speed and temperature. Audi has also said that it will recall the affected models for a software update.
According to a source close to Audi, the problem with the specific models lies to the interaction between transmission and engine control units, leading to an emissions overshoot.