Testing if checkbox is checked after update on Access Form

I have a frame with two choices (checkboxes).  After I set the focus to the frame, I want to test whehter one or the other checkbox is checked.  After I test the condition, I want to disable the unchecked box and set focus to the next frame or text box.

I am getting an error the expression has no value.  Here is my code:

Private Sub Frame50_AfterUpdate()
    If Me.Check53 = True Then
        Me.Check55.Enabled = False
    Else
        Me.Check53.Enabled = False
    End If
   
    Me.Check_162 = False
    Me.Check167 = False
    Me.Check169 = False
    Me.Check_162.SetFocus
End Sub

What is the proper syntax?

Thank you

Glen