i am facing like same issue by using
mb_convert_encoding($row[$nameField['mapp_field']], 'ISO-8859-1', 'UTF-8');
i am importing csv data in wp..the string from csv is
"TV-Komb. mit VitrinenTŸren BEST"
..issue is to print "Ÿ". result of php code is
"TV-Komb. mit VitrinenT?ren BEST?"