G400 CDI- suddenly went out and stopped starting.

Hello together, now I also have a problem with the G. The following has happened: I drove quite normal and all of a sudden the car went from now on without warning – no stutter, nothing. The tank had gone before about 10km on reserve, but the G has 20ltr reserve- so it can not lie there, and also had no problems with it so far – that is enough mathematically for about 150km. Then I thought that the tanker does not properly indicate, 20ltr diesel reinges chüttet, but nothing happens- nurser turns, but the motor doesn’t start. Will have it picked up today from MB, what can it be like? Greetings