A control system includes a first electronic control unit (30) configured to control the engine (100) and a second electronic control unit (40) configured to control the rotary electric machine (200, 400). The second electronic control unit (40) is configured to output an engine command signal to the first electronic control unit (30) through communication with the first electronic control unit (30). The first electronic control unit (30) is configured to: control the engine in accordance with the engine command signal received from the second electronic control unit (40), when a communication abnormality with the second electronic control unit (40) does not occur; and execute fixing operation control in which the engine (100) is controlled such that at least one of speed, output power, and output torque of the engine (100) becomes a corresponding fixed value, when the communication abnormality with the second electronic control unit (40) occurs.