Index: firmware/App/Modes/OperationModes.c
===================================================================
diff -u -r0bf1c0824844ed4c227eef0323238daedf505dc7 -r80028d3b1eef322950c1a5b74c282df2ba989ff5
--- firmware/App/Modes/OperationModes.c	(.../OperationModes.c)	(revision 0bf1c0824844ed4c227eef0323238daedf505dc7)
+++ firmware/App/Modes/OperationModes.c	(.../OperationModes.c)	(revision 80028d3b1eef322950c1a5b74c282df2ba989ff5)
@@ -69,6 +69,7 @@
 // ********** private function prototypes **********
 
 static DG_OP_MODE_T arbitrateModeRequest( void );
+static void exitCurrentOperationMode( DG_OP_MODE_T oldMode );
 static void transitionToNewOperationMode( DG_OP_MODE_T newMode );
 static void broadcastOperationMode( void );
 
@@ -134,6 +135,7 @@
     if ( currentMode != newMode )
     {
         // handle transition to new mode
+        exitCurrentOperationMode( currentMode );
         transitionToNewOperationMode( newMode );
         currentMode = newMode;
     }
@@ -270,6 +272,28 @@
 
 /*********************************************************************//**
  * @brief
+ * The exitCurrentOperationMode function undergo the process of exit the
+ * current operation mode.
+ * @details Inputs: none
+ * @details Outputs: clean up when exit current mode
+ * @param oldMode old op mode to clean up
+ * @return none
+ *************************************************************************/
+static void exitCurrentOperationMode( DG_OP_MODE_T oldMode )
+{
+    switch ( oldMode )
+    {
+        case DG_MODE_FILL:
+            exitFillMode();
+            break;
+        default:
+            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DG_SOFTWARE_FAULT, 0, (U32)oldMode )     // TODO - add s/w fault enum to 1st data param
+            break;
+    }
+}
+
+/*********************************************************************//**
+ * @brief
  * The transitionToNewOperationMode function undergo the process of transition
  * to new operation mode.
  * @details Inputs: none