I assume you have a function 'FileFolderExists' somewhere, since that's not a native VBA function.
Try:
Code:
Private Sub TestFileExistence()
If Dir("\\cf3.pepsico.pvt\psra\Output\BI 4\Exec Dollars - Current Period.pdf", vbNormal) <> "" Then
If Weekday(Date) = 2 Then
Range("A1").Value = "X"
Else
Range("A1").Value = "!"
End If
Else
Range("A1").Value = "!"
End If
End Sub