diff --git a/Lib/tabnanny.py b/Lib/tabnanny.py
index 7053fd9..a4d4ef0 100755
--- a/Lib/tabnanny.py
+++ b/Lib/tabnanny.py
@@ -93,11 +93,8 @@
                 check(fullname)
         return
 
-    with open(file, 'rb') as f:
-        encoding, lines = tokenize.detect_encoding(f.readline)
-
     try:
-        f = open(file, encoding=encoding)
+        f = tokenize.open(file)
     except IOError as msg:
         errprint("%r: I/O Error: %s" % (file, msg))
         return