Private Sub Workbook_Open()
Dim C As Range
For Each C In Sheets("Feuil1").Range("ProVid")
If C - C.Offset(0, -1) >= 500 Then
If C >= C.Offset(0, -1) Then MsgBox C.Offset(0, -2).Value & ": la vidange est dépassée de " & _
Val(C) - Val(C.Offset(0, -1)) & " Kms"
End If
If C - C.Offset(0, -1) <= 500 And C - C.Offset(0, -1) > 500 Then
If C >= C.Offset(0, -1) Then MsgBox C.Offset(0, -2).Value & ": la vidange est prévue dans " & _
Abs(Val(C.Offset(0, -1) - Val(C))) & " Kms"
End If
Next C
End Sub