The Federal Motor Transport Authority (KBA) completed its investigation on diesel vehicles, with their results showing that only Volkswagen has cheated the official emission tests.
According to Reuters, the study found irregularities during on-road testing of emission levels in other cars but these were within the legal limits.
The investigation included more than 50 diesel models from 23 brands and started in last September, after VW admitting manipulation of the emissions tests, using the so-called defeat devices for up to 11 million vehicles worldwide.
The German newspaper Handelsblatt also wrote that the full report of KBA will be released in late April, with a spokesman from the Transport Ministry saying “the final results will be published after the end of the investigation”.
VW has seen its sales dropping by 12.5 per cent in the United States for the first quarter of 2016, with Audi’s and Porsche’s remaining unaffected in the region by the emission-cheating scandal.