But Der Spiegel said that the KBA vehicle licensing authority is now set to recall some Mercedes-Benz Vito vans produced by Daimler, as well.
The suspicions this time concern a software device that regulates the amount of a special fluid known as AdBlue used in the engines to neutralise harmful nitrogen oxides (NOx).
Nitrogen oxides are poisonous, can contribute to acid rain and suffocating smog and can cause breathing problems and headaches in humans.
"We are in a technical exchange with the KBA," about the vans, a Daimler spokesman told AFP, saying around 1,000 of the 1.6-litre models were affected in Germany.
Quoting transport ministry sources, Der Spiegel reported that officials in Berlin believe the software amounts to an "illegal defeat device", designed to cheat regulators emissions tests.
"Whats more, it is believed that this kind of manipulation could be found elsewhere" in Daimlers range, the weekly added.
But Daimler denied any wrongdoing.
"We would take all legal means against the allegation of a defeat device," the Daimler spokesman said, while adding the firm would "continue to cooperate fully with the authorities".
VW also remains in officials sights.
KBA investigators have discovered "questionable" software functions in Macan SUVs produced by VWs subsidiary Porsche and could rescind the luxury cars licenses, Der Spiegel reported.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)