Abstract: An electric control unit is used to generate control signals for the alternator-starter assembly on the basis of first information signals representative of a state of the vehicle and a control unit is used to generate control signals for power circuits on the basis of diagnosis signals representative of the state of the alternator-starter assembly. The control signals are generated using the electronic control unit also on the basis of at least one first diagnosis signal, and control signals are generated using the control circuit also on the basis of second information signals from a data communication bus.