diff --git a/gradle.properties b/gradle.properties
index 4cf7d37a..5af85ba3 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -25,4 +25,4 @@ assertj_version    = 3.21.0
 junit_version      = 5.8.2
 
 # Version of published artifacts
-version            = 7.8.3
+version            = 7.8.4
diff --git a/language/src/main/java/de/monticore/lang/sysmlv2/SysMLv2Tool.java b/language/src/main/java/de/monticore/lang/sysmlv2/SysMLv2Tool.java
index bb49c544..c8960180 100644
--- a/language/src/main/java/de/monticore/lang/sysmlv2/SysMLv2Tool.java
+++ b/language/src/main/java/de/monticore/lang/sysmlv2/SysMLv2Tool.java
@@ -41,6 +41,12 @@
 import de.monticore.lang.sysmlv2.cocos.TypeCheckTransitionGuards;
 import de.monticore.lang.sysmlv2.cocos.TypeCheck3TransitionGuards;
 import de.monticore.lang.sysmlv2.cocos.WarnNonExhibited;
+import de.monticore.lang.sysmlv2.cocos.PartTypeDefinitionExistsCoCo;
+import de.monticore.lang.sysmlv2.cocos.ParentComponentInputConnectionDirectionCoCo;
+import de.monticore.lang.sysmlv2.cocos.QualifiedPortNameExistsCoCo;
+import de.monticore.lang.sysmlv2.cocos.RefinementTargetDefinitionExistsCoCo;
+import de.monticore.lang.sysmlv2.cocos.SubcomponentOutputConnectionDirectionCoCo;
+import de.monticore.lang.sysmlv2.cocos.UniqueSubPartNamesInConnectionCoCo;
 import de.monticore.lang.sysmlv2.symboltable.completers.CausalityCompleter;
 import de.monticore.lang.sysmlv2.symboltable.completers.DirectRefinementCompleter;
 import de.monticore.lang.sysmlv2.symboltable.completers.DirectionCompleter;
@@ -167,6 +173,16 @@ public void runAdditionalCoCos(
     checker.addCoCo(new PortDefinitionExistsCoCo());
     checker.addCoCo(new PartBehaviorCoCo());
 
+    // Check Definitions exist
+    checker.addCoCo(new PartTypeDefinitionExistsCoCo()); 
+    checker.addCoCo(new RefinementTargetDefinitionExistsCoCo()); 
+
+    // Connection CoCos
+    checker.addCoCo(new UniqueSubPartNamesInConnectionCoCo()); 
+    checker.addCoCo(new QualifiedPortNameExistsCoCo()); 
+    checker.addCoCo(new SubcomponentOutputConnectionDirectionCoCo()); 
+    checker.addCoCo(new ParentComponentInputConnectionDirectionCoCo()); 
+
     checker.checkAll(ast);
   }