Replace Character With Another

I'm trying to go through a short list of letters and change the contents of every cell in the list that contains a "c" into a "M". I've written this code, but I get a #Value! message on my spreadsheet when I run it:


Function FindCpmDpm(SearchRng As Range)

Dim CelRng As Range

For Each CelRng In SearchRng

If CelRng.Value = "c" Then
CelRng.Value = "M"
End If

Next CelRng

End Function

I am having trouble accessing the cell which contains the "c".