Dieselgate has, for the most part, come and gone, but now it looks like there might be another scandal on the horizon – this time involving the gasoline-powered engines found in the 2008-2013 Porsche 911 and Panamera. As of now, Porsche won’t say for sure, but it has launched an internal investigation and alerted the proper authorities.

911 and Panamera Emissions Cheating: An Ongoing Investigation

The said misconduct revolves around alleged and specific changes made to manipulate exhaust gas emissions at the hardware and software level – similar to the filter-switching that was used to manipulate various diesel engines supplied to Porsche by Audi.

According to a statement made to Handelsblatt newspaper, Porsche has already alerted the KBA, Stuttgart public prosecutor, and U.S. authorities about the misconduct, apparently back as far as “early summer.” The KBA has since opened its own investigation into Porsche’s claims alongside Porsche’s own internal investigation. At the same time, Audi is facing allegations of the same in gasoline-powered engines, a case that has been brought before the Offenburg District Court in Germany.

According to that case, the 2.0-liter, turbocharged, four-cylinder engine in the Audi Q5 is manipulated based on the position of the steering wheel (via the steering wheel sensor.) In certain positions, the computer system will switch off the selective catalytic reduction filter, which in turn triggers a higher level of NOx emissions than anything found during official testing.

This sensor has already been known to be a catalyst for the cheating found in diesel engine emissions. Based on the reading of the sensor, the built-in computer system can determine whether or not the car is on a rolling road – which it wouldn’t be during emissions testing – and then switches off the filter. This does provide a boost in performance at the cost of higher emissions output. Court papers say that emissions are elevated by up to 24.5-percent when the Audi Q5 2.0 TFSO turns off the exhaust gas filter.

As of now, there’s no way to know what will happen, but it sounds like Audi is going to be in even more hot water – and possibly Porsche as well if the company can’t prove that it wasn’t aware of it at the time. Alerting authorities early on is a good move on Porsche’s part, but it looks like Dieselgate might morph into Petrolgate at this point.