diff -r dbe69f54b09c Lib/subprocess.py
--- a/Lib/subprocess.py	Wed Jun 01 13:54:33 2016 -0700
+++ b/Lib/subprocess.py	Thu Jun 02 19:44:59 2016 +0300
@@ -925,16 +925,22 @@
         if p2cwrite != -1:
             self.stdin = io.open(p2cwrite, 'wb', bufsize)
             if universal_newlines:
+                enc = os.device_encoding(0) if (stdin == PIPE) else None
                 self.stdin = io.TextIOWrapper(self.stdin, write_through=True,
+                                              encoding=enc,
                                               line_buffering=(bufsize == 1))
         if c2pread != -1:
             self.stdout = io.open(c2pread, 'rb', bufsize)
             if universal_newlines:
-                self.stdout = io.TextIOWrapper(self.stdout)
+                enc = os.device_encoding(1) if (stdout == PIPE) else None
+                self.stdout = io.TextIOWrapper(self.stdout,
+                                               encoding=enc)
         if errread != -1:
             self.stderr = io.open(errread, 'rb', bufsize)
             if universal_newlines:
-                self.stderr = io.TextIOWrapper(self.stderr)
+                enc = os.device_encoding(2) if (stderr == PIPE) else None
+                self.stderr = io.TextIOWrapper(self.stderr,
+                                               encoding=enc)
 
         self._closed_child_pipe_fds = False
         try: