Electronic Control Unit and Method For Reducing Power Consumption of Electronic Control Unit

An electronic control unit includes a microcomputer configured to be started by a plurality of starting factors, in which different operation modes are associated with each of the starting factors, and a resource is associated with each of the operation modes. The microcomputer identifies a starting factor in an initialization process started by the starting factor, and selects and executes an operation mode associated with the starting factor identified. When another starting factor is generated during execution of the operation mode, the microcomputer stops execution of the operation mode and restarts, and then executes an operation mode associated with the other starting factor.