Audi cars allegedly fooled environmental regulators by emitting less carbon-dioxide on a testing mount than the cars allowed themselves to spew when on the road, the weekly German paper Bild am Sonntag reports. It’s the same trick that Audi and other Volkswagen brands had earlier used to defeat tests of their diesel cars’ emissions of nitrous oxides.

Nitrous oxides are a component of ground-level smog, which is harmful to health. Carbon emissions are a greenhouse gas.

Both the earlier scam and the current alleged scam were uncovered not in Europe—where most of the test-evasion took place—but in the United States. The nitrous oxides scandal—which has cost VW billions of dollars in fines and compensation and a recall of some 9 million cars—was discovered a year ago by engineers at West Virginia University’s Center for Alternative Fuels, Engines and Emissions. And the alleged evasion of carbon-emissions testing was found by the California Air Resources Board (CARB), in research conducted in both diesel and gasoline-powered Audis over the summer, the German paper reports.

So far neither Audi nor CARB have commented on the latest report.

The cars defeated the carbon test by using data from the wheels and steering wheel to figure out whether the car was up on a test mount. “If the steering wheel is not moved after the start, a shift program activates itself in automatic gearboxes, with which particularly little CO₂ is emitted; if the driver turns the steering wheel, this ‘warm-up strategy’ is deactivated,” says Bild am Sonntag, as rendered by Google Translate.

The Wall Street Journal reports that the carbon-dioxide cheat was discussed by high-level officials of VW and Audi at an event in South Africa in 2013, two years before the nitrous-oxide cheat came to light. “The shifting program needs to be configured so that it runs at 100 percent on the treadmill but only 0.01 percent with the customer,” said Axel Eiser, the head of Audi’s powertrain division, according minutes of the discussions that the newspaper cites.