Control system and control method for vehicle

A control method for a vehicle including at least one actuator, a plurality of request generation devices each of which is mounted with at least one application that independently generates a request to the actuator and each of which outputs a single first request and a single second request that are based on the request generated by the at least one application, an arbitrator that arbitrates the first requests and the second requests from the plurality of request generation devices and that outputs a self-output first request and a self-output second request, and an actuator control apparatus that controls the actuator based on a final request that is obtained by arbitrating the self-output first request and the self-output second request from the arbitrator and a request made by a driver of the vehicle, the control method comprising:

• causing the actuator control apparatus to transmit the final request to the arbitrator;
• causing the arbitrator to specify a request generation device of the plurality of request generation devices that has output the first or second request corresponding to the final request, based on the final request from the actuator control apparatus, a self-output first request, and a self-output second request, and to notify the plurality of request generation devices of a result of specification;
• and
• causing the request generation device specified by the arbitrator to specify the application that has generated the request corresponding to the final request, based on the self-output first request, the self-output second request, and the request made by the driver.