Data validation for certain columns between other columns only - excel

Question

Hey guys I am trying to change a code that I wrote for an excel vba Data validation tool. This is the first table i used:
Now I have another table with additional variables :
When I reuse the code from the first one (shown below) the columns on the right of length/width and height are also checked. I only want the three columns to be checked. I tried setting the variable lCol to 3 but then only C2 and the values below are checked. How can i apply the code only to the columns B/C/D without including the ones on the right without changing up the code completely?
Any help is appreciated!
Sub CheckColumnsTransportationMean()
Dim rng As Range
Dim lCol As Long, lRow As Long
Dim DblLengthMin As Double
Dim DblLengthMax As Double
Dim dynamicArray1() As String
Dim dynamicArray2() As String
Dim f1 As Integer
Dim f2 As Integer
f1 = 0
f2 = 0
ReDim Preserve dynamicArray1(0)
ReDim Preserve dynamicArray2(0)
DblLengthMax = 20000
DblLengthMin = 5
lCol = Range("C2").End(xltoRight).Column
lRow = Range("C2").End(xlDown).Row
For Each rng In Range("C2", Cells(lRow, lCol))
If IsNumeric(rng) = False Then
f1 = f1 + 1
rng.Interior.ColorIndex = 3
ReDim Preserve dynamicArray1(0 To f1)
dynamicArray1(f1) = "Row " & rng.Row & " Column " & rng.Column & " wrong
entry: " & rng.Value
End If
If IsNumeric(rng) And rng.Value > DblLengthMax Or rng.Value < DblLengthMin Then
f2 = f2 + 1
rng.Interior.ColorIndex = 46
ReDim Preserve dynamicArray2(0 To f2)
dynamicArray2(f2) = "Row " & rng.Row & " Column " & rng.Column & " wrong entry: " &
rng.Value
End If
Next rng
Inhalt1 = Join(dynamicArray1, vbCrLf)
MsgBox ("Wrong datatype! " & vbCrLf & vbCrLf & f1 & " Datatype Errors (marked red)" &
vbCrLf & "Only numbers can be entered. Check again" & vbCrLf & Inhalt1)
Inhalt2 = Join(dynamicArray2, vbCrLf)
MsgBox ("Entries out of range!" & vbCrLf & vbCrLf & f2 & " Range errors (marked
orange)" & vbCrLf & "The value is out of range. Check for unit [mm] " & vbCrLf &
Inhalt2)
End Sub