You need to log onto the SC and run these commands;
esxcfg-vswitch -l (lists all your vswitches and port groups)
Find the portgroup name that has the SC assigned to it (usually port group 0)
esxcfg-vswitch vSwitch0 -p “portgroup name” -v “VLANID” or
esxcfg-vswitch vSwitch0 -p “portgroup name” -v 0 to disable the VLANID