Another Volkswagen subsidiary is in the hot seat over car emissions testing.

German officials are reportedly investigating luxury sportscar brand Porsche based on claims it disguised vehicles' carbon dioxide emissions under test conditions.

According to Reuters, the Motor Transport Authority (KBA) is "examining software to see whether it could measure the angle of a car's steering wheel."

The California Air Resources Board (CARB) over the summer discovered a similar device used to lower Audi vehicles' exhaust emissions under test conditions.

The technology—installed in Audis with diesel and gas engines in the US and abroad—detects when a car's steering wheel is dormant, suggesting it is in lab-testing mode, and lowers its emissions output. If the wheel is turned in any direction more than 15 degrees, indicating normal driving mode, the gadget turns off and the car returns to elevated emissions output.

In September 2015, the California regulator began using enhanced detection and screening procedures on all modern vehicles—diesel or gasoline—to find undisclosed devices that impact emissions. Audi reportedly stopped using the software in May, and suspended several engineers.

Volkswagen, Porsche, and the KBA did not immediately respond to PCMag's request for comment.

Volkswagen in September 2015 admitted that 11 million of its diesel cars featured software that recognized when the car was undergoing official emissions testing.

The Department of Justice, on behalf of the Environmental Protection Agency, sued VW, Audi, and Porsche for violating EPA standards and the Clean Air Act. Volkswagen in January proposed a catalytic converter fix for up to 430,000 vehicles affected by the emissions scandal.

It turns out the apple doesn't fall far from the automotive tree.

Germany's WirtschaftsWoche first reported the Porsche probe on Thursday.