Problem using a variable to save a workbook as a .csv

Hi there..
I have a script that calls several macros. I have it working to the point where it saves a variable in cell M1.
I'm trying to get it to save the workbook as a .csv using the M1 Variable. It will be a different value each time I run it.
I am seeing subscript out of range errors. Is this because the cell has no value when this macro tries to execute?

Sub exportcsv()
Application.DisplayAlerts = False
Sheets("csv").Select
Dim LIMSnumber
LIMSnumber = Range("M1")
ChDir "C:\1_macros\csv"
ActiveWorkbook.SaveAs Filename:="C:\1_macros\csv\" & LIMSnumber & ".csv", FileFormat:= _
xlCSV, CreateBackup:=False
ActiveWorkbook.Close (SaveChanges = True)
End Sub

Thank you for your help.

I think so if cell M1 is empty then LIMSnumber will be empty, so you are trying to save a file without a filename..

Try testing LIMSnumber after you filled it. and let the sub end if there is no value

Sub exportcsv()
Application.DisplayAlerts = False
Sheets("csv").Select
Dim LIMSnumber
LIMSnumber = Range("M1")
If  Limsnumber is Nothing then exit sub
ChDir "C:\1_macros\csv"
ActiveWorkbook.SaveAs Filename:="C:\1_macros\csv\" & LIMSnumber & ".csv", FileFormat:= _
xlCSV, CreateBackup:=False
ActiveWorkbook.Close (SaveChanges = True)
End Sub

Thanks Roel
That doesn't help. I made a new document with just the last macro. In M1 I typed Test. Now I'm seeing runtime error 9 subscript out of range Debug identifies: Sheets("csv").Select ??

I solved it myself !!!!

Sub saveascsv()
Dim AC As String: AC = Sheets("Sheet1").Range("M1").Value

    ActiveWorkbook.SaveAs Filename:= _
    "C:\1_temp\" & AC & ".csv", FileFormat:= _
xlCSV, CreateBackup:=False
         
End Sub