Abstract: In accordance with the described embodiments vehicular electronic control units and their operating methods are described which cost effectively compensate momentary external power loss by reducing the unit's power consumption while external power is lost. In an exemplary embodiment external power loss is detected by the electronic control unit's microprocessor. The microprocessor thereupon disables some components within the electronic control unit and operates with limited functionality for the duration of external power loss. The electronic control unit uses internal energy storage, e.g. a hold capacitor, to sustain its limited functionality operation. Upon recovery from the external power loss the electronic control unit resumes full operation.