A vehicle control system comprising: a plurality of sensors; a central control device configured to calculate target outputs of a plurality of actuators, based on outputs of the respective sensors; and a plurality of relay devices each disposed in a communication path between the central control device and a corresponding actuator among the actuators and configured to relay a signal transmitted from the central control device, wherein the central control device includes a central abnormality diagnosis unit configured to diagnose an abnormality in the central control device, the plurality of relay devices include a specific relay device that is a relay device configured to transfer a control signal from the central control device only to a specific actuator, the specific relay device being configured to output, to the specific actuator coupled to the specific relay device, one of a signal for setting the specific actuator in an operating state or a signal for setting the specific actuator in a non-operating state, in response to the central abnormality diagnosis unit detecting an abnormality in the central control device, and the specific relay device does not have a function of diagnosing an abnormality in the specific relay device, characterized in that T the specific actuator is an actuator not related to driving control, braking control, and steering control of a vehicle among the actuators, the specific relay device outputs, to the specific actuator coupled to the specific relay device, one of the signal for setting the specific actuator in the operating state or the signal for setting the specific actuator in the non-operating state, also in response to an abnormality in a state of communication between the specific relay device and the central control device, the specific relay device is configured to be capable of communicating with the central control device via another relay device, the other relay device includes a communication diagnosis unit configured to detect an abnormality in a state of communication between the other relay device and the central control device, and the specific relay device outputs, to the specific actuator coupled to the specific relay device, one of the signal for setting the specific actuator in the operating state or the signal for setting the specific actuator in the non-operating state, in response to the communication diagnosis unit of the other relay device detecting an abnormality in the state of communication between the other relay device and the central control device. a plurality of sensors; a central control device configured to calculate target outputs of a plurality of actuators, based on outputs of the respective sensors; and a plurality of relay devices each disposed in a communication path between the central control device and a corresponding actuator among the actuators and configured to relay a signal transmitted from the central control device, wherein the central control device includes a central abnormality diagnosis unit configured to diagnose an abnormality in the central control device, the plurality of relay devices include a specific relay device that is a relay device configured to transfer a control signal from the central control device only to a specific actuator, the specific relay device being configured to output, to the specific actuator coupled to the specific relay device, one of a signal for setting the specific actuator in an operating state or a signal for setting the specific actuator in a non-operating state, in response to the central abnormality diagnosis unit detecting an abnormality in the central control device, and the specific relay device does not have a function of diagnosing an abnormality in the specific relay device, characterized in that T the specific actuator is an actuator not related to driving control, braking control, and steering control of a vehicle among the actuators, the specific relay device outputs, to the specific actuator coupled to the specific relay device, one of the signal for setting the specific actuator in the operating state or the signal for setting the specific actuator in the non-operating state, also in response to an abnormality in a state of communication between the specific relay device and the central control device, the specific relay device is configured to be capable of communicating with the central control device via another relay device, the other relay device includes a communication diagnosis unit configured to detect an abnormality in a state of communication between the other relay device and the central control device, and the specific relay device outputs, to the specific actuator coupled to the specific relay device, one of the signal for setting the specific actuator in the operating state or the signal for setting the specific actuator in the non-operating state, in response to the communication diagnosis unit of the other relay device detecting an abnormality in the state of communication between the other relay device and the central control device.