diff --git a/src/main/java/avatartranslator/tosysmlv2/javacup/AvatarFromSysML.jcup b/src/main/java/avatartranslator/tosysmlv2/javacup/AvatarFromSysML.jcup
index cbb42481665320f2e940009a9221dbc7514926b3..08f6a6983239af866044ec9d6b6bc3f20e8844aa 100644
--- a/src/main/java/avatartranslator/tosysmlv2/javacup/AvatarFromSysML.jcup
+++ b/src/main/java/avatartranslator/tosysmlv2/javacup/AvatarFromSysML.jcup
@@ -477,6 +477,9 @@ syncChDecl ::= PART:p IDENT:id COLON SYNC_T EQUAL SYNC_T LPAR RELATION_F EQUAL I
         addError( new AvatarFromSysMLError(AvatarFromSysMLError.LOWERROR, pxleft, "Channel " + id.getAvatarName() +
         " is already declared", theChannel.getLeft()) );
     } else {
+        if (theRelation.getAsynchronous())
+            addError(new AvatarFromSysMLError(AvatarFromSysMLError.HIGHWARNING,
+                pxleft, "synchroneous channels require a synchroneous relation\n"));
         theRelation.addChannel(theChannel);
         theChannel.setLeft(pxleft);
         theChannel.setRight(sxright);
@@ -489,6 +492,9 @@ nbfChDecl ::= PART:p IDENT:id COLON NBFIFO_T EQUAL NBFIFO_T LPAR RELATION_F EQUA
         addError( new AvatarFromSysMLError(AvatarFromSysMLError.LOWERROR, pxleft, "Channel " + id.getAvatarName() +
         " is already declared", theChannel.getLeft()) );
     } else {
+        if (! theRelation.getAsynchronous())
+            addError(new AvatarFromSysMLError(AvatarFromSysMLError.HIGHWARNING,
+                pxleft, "FIFO channels require an asynchroneous relation\n"));
         theRelation.addChannel(theChannel);
         theChannel.setLeft(pxleft);
         theChannel.setRight(sxright);
@@ -501,6 +507,9 @@ bfChDecl ::= PART:p IDENT:id COLON BFIFO_T EQUAL BFIFO_T LPAR RELATION_F EQUAL I
         addError( new AvatarFromSysMLError(AvatarFromSysMLError.LOWERROR, pxleft, "Channel " + id.getAvatarName() +
         " is already declared", theChannel.getLeft()) );
     } else {
+        if (! theRelation.getAsynchronous())
+            addError(new AvatarFromSysMLError(AvatarFromSysMLError.HIGHWARNING,
+                pxleft, "FIFO channels require an asynchroneous relation\n"));
         theRelation.addChannel(theChannel);
         theChannel.setLeft(pxleft);
         theChannel.setRight(sxright);