Asegurate de que tienes una ruta configurada apuntando a tu nuevo controlador.
https://book.cakephp.org/2.0/en/development/routing.html
https://book.cakephp.org/3.0/en/development/routing.html
https://book.cakephp.org/2.0/en/development/routing.html
https://book.cakephp.org/3.0/en/development/routing.html