diff --git a/fhem/FHEM/36_LaCrosse.pm b/fhem/FHEM/36_LaCrosse.pm
index 1982aa75b..90754e8d7 100644
--- a/fhem/FHEM/36_LaCrosse.pm
+++ b/fhem/FHEM/36_LaCrosse.pm
@@ -197,7 +197,7 @@ LaCrosse_Parse($$)
         $rhash = $defs{$d};
         $raddr = $rhash->{addr};
 
-        Log3 $name, 3, "LaCrosse Changing device $rname from $raddr to $addr";
+        Log3 $name, 3, "LaCrosse: Changing device $rname from $raddr to $addr";
 
         delete $modules{LaCrosse}{defptr}{$raddr};
         $rhash->{DEF} = $addr;
@@ -211,8 +211,10 @@ LaCrosse_Parse($$)
         return "";
       }
     }
-    Log3 $name, 3, "LaCrosse Unknown device $rname, please define it";
+    Log3 $name, 3, "LaCrosse: Unknown device $rname, please define it";
 
+    Log3 $name, 3, "LaCrosse: check commandref on usage of LaCrossePairForSec" if( !$hash->{LaCrossePair} && !defined($modules{LaCrosse}{defptr}) );
+   
     return "" if( !$hash->{LaCrossePair} );
 
     return "UNDEFINED LaCrosse_$rname LaCrosse $raddr" if( $battery_new || $hash->{LaCrossePair} == 2 );