Sub Remplacer()
Application.ScreenUpdating = 0
For i = 6 To Range("j65536").End(xlUp).Row
If Range("j" & i).Offset(0, -4) = "C" And Range("j" & i).Offset(0, -3) = "D" _
Then Range("j" & i).Value = Range("g2").Value
Next
Application.ScreenUpdating = -1
End Sub