Germany’s transport authority (KBA) is investigating Porsche vehicles for the presence of software that can detect when a vehicle is being tested for emissions, the German weekly Wirtschaftswoche reports. The software has been found in a number of VW Group models since the outbreak of the diesel crisis nearly two years ago, though this is the first time Porsche models have been reported to be under the microscope.

The emissions software (which has not been found in any Porsche model to date) works by detecting steering wheel movement and adjusting a vehicle’s emissions outputs accordingly. The software is said to operate by allowing the vehicle’s emissions control system to emit more than the permitted level of nitrogen oxides if it detects steering inputs of greater than 15 degrees.

The KBA tests follow the ministry’s demand that Audi recall some 24,000 A7 and A8 models equipped with the 3.0-liter V6 diesel and 4.2-liter V8 diesel engines, which the ministry accused of emitting twice the permitted level of pollutants. VW Group CEO Matthias Mueller was reportedly summoned to the KBA last week in connection with the probe.
 

The Wirtschaftswoche report follows last week’s warning by Porsche Automobil Holding SE that the company’s offices may be searched as a part of the German government’s investigation into the diesel crisis. Multiple Audi offices and factory sites were searched by prosecutors and police in March of this year.

So far, the Porsche Cayenne Diesel is the sole Porsche model to be issued a Notice of Violation by the EPA for a different type of undisclosed software, which was said to be part of a diesel engine’s “warmup” technique. The EPA action effectively grounded a number of Audi and VW models as a part of the 3.0-liter diesel investigation, forcing VW Automotive Group to develop a software patch for the affected models that has only recently received approval.