Mubasher: German automaker Daimler may have used emission-cheating software to pass tests on diesel vehicles, German newspaper Bild am Sonntag reported, citing documents by US investigators.

Investigators in the US reportedly found a function called "Bit15" that turns off emissions cleaning after 26 kilometres of driving, which helps the Mercedes owner fool the test.

These reports compared Daimler’s illegal actions with Volkswagen’s emission scandal in September 2015 when the latter included a “defeat device” software to switch off the emission control system when the car is tested.

The German automaker refused to comment on these documents, stating that it has been working closely with authorities for more than two years, according to Bild am Sonntag.