Petición JSON mediante AFHTTPSessionManager

NSArray *campos = [NSArray arrayWithObjects:@"dato001",@"dato002", nil];
    NSArray *valores = [NSArray arrayWithObjects:dato001,dato002, nil];
    NSDictionary *diccionario = [NSDictionary dictionaryWithObjects:valores forKeys:campos];
    
    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];

    manager.responseSerializer = [AFJSONResponseSerializer serializer];
    manager.responseSerializer = [AFHTTPResponseSerializer serializer];
    
    [manager POST:URL_PETICION parameters:diccionario progress:nil success:^(NSURLSessionTask *task, id responseObject) {
        
        NSDictionary* json = [NSJSONSerialization
                              JSONObjectWithData:responseObject
                              options:kNilOptions
                              error:nil];
        
        if ([[json objectForKey:@"success"] intValue] == 1) {
            
        }
    
    } failure:^(NSURLSessionTask *operation, NSError *error) {
        
        NSLog(@"Error: %@", error.localizedDescription );
        
        NSMutableString *mensaje = [[NSMutableString alloc] init];
        [mensaje appendString:NSLocalizedString(@"Fallo en la conexión", nil)];
        
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Información",nil) message:mensaje delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
        [alert show];
        
    }];