Can't load controller function, codeigniter 3.x

I'm having some issues trying to load a function from a JS in a view page. It works with others view page, but for some reason this one called sistemas_aplicaciones doesn't work, it can't find the controller in order to show the view page.

This is the submenu view that calls the function in controller.

Code:

    <?php
    defined("BASEPATH") OR exit("No direct script access allowed");
    ?>
    <script type="text/javascript" src="<?php echo base_url('assets/js/helper/func_administracion.js');?>"></script>
         <ul class="nav nav-stacked" id="accordion" role="tablist" aria-multiselectable="true">
                    <input type="hidden" id="id_menu_superior" value="{id_menu_superior}"/>
                    <input type="hidden" id="vista" value="{vista}"/>
        <li  class="active" id="0" role="tab" >
                        <a href="<?= base_url('{vista}/load_default_content')?>" id="call_default">
            <span><?= img(base_url("assets/img/ico12_treeleaf.gif"),FALSE)?> </span>
                 Acerca del M&oacute;dulo  {menu_superior}
            </a>  
                    </li>
        {submenu}
                    <li class="panel" id="{id_menu}" >      
          <a role="button" data-toggle="collapse" data-parent="#accordion" 
            href="#submenu_{id_menu}" aria-expanded="true" aria-controls="submenu_{id_menu}">
            <?= img(base_url("assets/img/1x1.gif"),FALSE,array("id"=>"folder_{id_menu}","class"=>"plus"))?>
            <?= img(base_url("assets/img/ico12_treefolder.gif"),FALSE)?> 
               {nombre}  
              </a>    
          <ul id="submenu_{id_menu}" class="nav collapse" role="tabpanel" aria-labelledby="{id_menu}">
      <li style="padding-left: 15px;">
      <!-- Here is where you call the controller function -->
          <a href="<?= base_url('{vista}/create')?>"  name="sub_m_{id_menu}_create" id="sub_m_{id_menu}_create" >
              <span><?= img(base_url("assets/img/ico12_treeleaf.gif"),FALSE)?> </span> 
              Agregar 
              </a>
          </li>
            <li style="padding-left: 15px;">
          <a href="<?= base_url('{vista}/search')?>"  name="sub_m_{id_menu}_search" id="sub_m_{id_menu}_search">
              <span><?= img(base_url("assets/img/ico12_treeleaf.gif"),FALSE)?> </span> 
              Consultar 
              </a>
            </li>
      </ul> 
  </li>
  {/submenu}
    </ul>

This view page will generate some buttons based on the id_menu loaded from a database called menu. when you click the agregar button it will execute a JS that will take the href and enter in the controller function create.

 

Code:

      $("ul.nav.collapse a").on("click", function(){
            $.ajax({
                type: 'POST',
                url: $(this).attr("href"),
                data: {},
                dataType: 'json',
                // Mostramos un mensaje con la respuesta de PHP
                success: function(data) {
                        $('#principal').html(data.mensaje);
                },
                error: function(error){
                    $('#principal').html('<div class="alert alert-warning alert-dismissible" role="alert">'+
                        '<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>'+
                        '<strong>Error!!!</strong> Solicitud de AJAX no completada->'+error.status+'</div>'); 
                }              
            }) ;
                return false;
        });
        
    });

The function will return an array of the view page of sistemas_aplicaciones and show it in the #principal tag. 

Like I said, this is working for the other controllers and view page in my project, but for sistemas_aplicaciones doesn't work, its showing an ajax error 404 not found. Can someone help me to understand why?