Well Mercedes paid the bulk of that €2.9 billion fine, which was for cartels involving truck building. I reckon cars being a much bigger thing.
Alarm bells should have started ringing when German subsidiaries all had similar engine sizes and outputs in their small diesels. If one can't do it honestly, they probably all can't.
As I understand it. VW (panicking because incriminating papers may have been seized during the deiselgate investigation) jumped in and confessed to the authorities, on the basis that the blabber gets off lightest, but Mercedes had beaten them to the punch.
Japan however takes it to another level. The world of manufacturer cartels out there revolves around the big Japanese banks.