diff --git a/pyren3/pyren3.py b/pyren3/pyren3.py
index be313db..9bf46e9 100755
--- a/pyren3/pyren3.py
+++ b/pyren3/pyren3.py
@@ -130,7 +130,7 @@ def optParser():
   parser.add_argument("--caf",
       help="turn on CAN Auto Formatting. Available only for OBDLink",
       dest="caf",
-      default=True,
+      default=False,
       action="store_true")
 
   parser.add_argument("--n1c",