My kia sorento 2008.. has been great until 3 weeks ago there is a whining sound when I drive over 40mph (which is most of the time) Then today when I was coming home the check engine light came on and so I stopped at the Auto Zone.. they coded me and then said they didn't know what it meant.. Please can someone give me ideas on the whining sound and what the Limp Home Valve Malfuntion is? It is still under warrenty.. I just do now want to go in and they try to do anything but fix it. Thanks Elli