It's been a rocky period for Volkswagen, to say the least. Indeed, the German manufacturer would probably rather forget the infamous Dieselgate scandal which has severely tarnished the German manufacturer's reputation across the globe. Unfortunately, it keeps coming back to haunt them because Porsche, which is also owned by VW, is now under investigation after insiders told German newspaper WirtshaftsWoche that the manufacturer is using a similar defeat device to pass emissions tests.

The investigation is being carried out by Germany's Motor Transport Authority, KBA, which is examining whether Porsche's cars are equipped with software that can detect whether the car is undergoing a laboratory test or on real roads. If the car was on a test bench, the device would engage a special test mode that drastically cuts CO2 emissions and fuel economy. Under the normal driving conditions, the device turns off which increases CO2 and fuel consumption. A similar investigation is also underway with Audi, which provides diesel engines to Porsche.

A Porsche spokesman has denied the allegations, saying that steering wheel movements were not used to detect whether a car was undergoing an emissions test. "This is not done with any Porsche models," the spokesman said, stressing that data is used to calculate shift points, not to activate a scandalous test mode. Potentially affected models in the US haven't been disclosed yet, but it's looking like the on-going nightmare is far from over for VW which is struggling to win back consumer confidence. Although owned by VW, Porsche and Audi were out of the equation in the initial scandal, so this could potentially be a huge blow for the German manufacturer.