Code to show/hide rows based on Y

Hi Justin
These mods get your code working:

Private Sub Worksheet_Change(ByVal Target As Range)

  If Target.Cells.Count > 1 Then Exit Sub
  
  If Not Intersect(Target, Worksheets("Codes").Range("c2:c440")) Is Nothing Then
     Select Case UCase(Target)
       Case Is = ""","","
         Target.EntireRow.Hidden = False
       Case Is = "Y"
         Target.EntireRow.Hidden = True
      End Select
  End If
  
End Sub

By the way the protocol on this forum is to wrap your code in Code Tags