A method and an apparatus for operating a control unit for controlling operational sequences in a vehicle. When operational sequences are error-free, the control functions of the built-in control unit are partially or completely suppressed. This allows additional functions to be switched in and out, and also allows modification and/or adaptation of data and/or programs that are accessed by the control functions. In the specific operating instance of the application, a further control unit is insertable into the vehicle wiring harness between the first control unit and a sensor arrangement, collection, group or system and an actuator arrangement, collection, group or system. The control functions suppressed in the control unit are then performable by the second control unit. The control unit then performs only the measurement functions and actuation functions The sequence is initiated and controlled by integrated remote-control functions, which are in addition to the normal or other functions. Since the second control unit is accessible and is designed in accordance with its application task, the application of the control unit may be performed using control functions exported therefrom.