diff --git a/pyren/mod_elm.py b/pyren/mod_elm.py
index 351344b..f48545a 100644
--- a/pyren/mod_elm.py
+++ b/pyren/mod_elm.py
@@ -1930,7 +1930,7 @@ class ELM:
         self.check_answer(self.cmd("at l0"))
         self.check_answer(self.cmd("at al"))
 
-        if mod_globals.opt_obdlink and mod_globals.opt_caf:
+        if mod_globals.opt_obdlink and mod_globals.opt_caf and not self.ATCFC0:
             self.check_answer(self.cmd("AT CAF1"))
             self.check_answer(self.cmd("STCSEGR 1"))
             self.check_answer(self.cmd("STCSEGT 1"))
diff --git a/pyren/pyren.py b/pyren/pyren.py
index 6a43e39..a94a2b6 100755
--- a/pyren/pyren.py
+++ b/pyren/pyren.py
@@ -130,7 +130,7 @@ def optParser():
   parser.add_argument("--caf",
       help="turn on CAN Auto Formatting. Available only for OBDLink",
       dest="caf",
-      default=False,
+      default=True,
       action="store_true")
 
   parser.add_argument("--n1c",