When a diagnostic period of a specific failure arrives, a management center transmits, to a vehicle, an instruction to order execution of a failure diagnosis of the specific failure. When an ECU of the vehicle receives the instruction to order execution of the failure diagnosis from the management center, the ECU of the vehicle determines whether or not the failure diagnosis can be executed. When the failure diagnosis cannot be executed, the ECU causes the vehicle to continue traveling without executing the failure diagnosis, and ends a process. In this case, the ECU postpones the failure diagnosis in the current diagnostic period, and executes the failure diagnosis when a next diagnostic period arrives. When the ECU determines that the failure diagnosis can be executed, the ECU executes the failure diagnosis.