ActionCondition()

override bool ActionCondition	(	PlayerBase	player,
		ActionTarget	target,
		ItemBase	item )

См. определение в файле ActionStartEngine.c строка 26

    {
        HumanCommandVehicle vehCommand = player.GetCommand_Vehicle();
        if (!vehCommand)
            return false;
        
        auto vehicle = CarScript.Cast(vehCommand.GetTransport());
        if (!vehicle || vehicle.EngineIsOn())
            return false;
        
        return vehicle.CrewDriver() == player;
    }

Перекрестные ссылки ActionTarget() и HumanCommandVehicle::GetTransport().