Index: firmware/App/Modes/FPModes/FPOperationModes.c
===================================================================
diff -u -r9d351536b78c540aec7c2a1cd5d23e88df856d6f -ra36dcbc3e2f94d418d8aa54588c836a3adf35e17
--- firmware/App/Modes/FPModes/FPOperationModes.c	(.../FPOperationModes.c)	(revision 9d351536b78c540aec7c2a1cd5d23e88df856d6f)
+++ firmware/App/Modes/FPModes/FPOperationModes.c	(.../FPOperationModes.c)	(revision a36dcbc3e2f94d418d8aa54588c836a3adf35e17)
@@ -47,8 +47,8 @@
 static U32 broadcastModeIntervalCtr;                                            ///< Interval counter used to determine when to broadcast operation mode.  Initialize to 11 to stagger broadcast.
 static U32 currentSubState;                                                     ///< current sub state.
 static U32 current4thLevelState;                                                ///< current 4th level state.
-static U32 requestedSubMode;                                                    ///< Requested operation sub mode.
-static BOOL changeSubMode;                                                      ///< Flag to determine change operation sub mode request status.
+static U32 testRequestedSubMode;                                                ///< Requested operation sub mode from dialin.
+static BOOL testChangeSubMode;                                                  ///< Flag to determine change operation sub mode request status.
 static BOOL isDeviceDefeatured;                                                 ///< bool to determine defeatured status
 static BOOL isBoostInstalled;                                                   ///< bool to determine boost pump status
 
@@ -72,6 +72,8 @@
 static FP_OP_MODE_T arbitrateModeRequest( void );
 static void transitionToNewOperationMode( FP_OP_MODE_T newMode );
 static void broadcastOperationMode( void );
+static void requestNewFPOperationSubMode( void );
+static BOOL validateSubModeChangeRequest( U32 reqSubMode );
 
 /*********************************************************************//**
  * @brief
@@ -96,8 +98,8 @@
     currentSubMode           = 0;
     currentSubState          = NO_FP_SUB_STATE;
     current4thLevelState     = NO_FP_SUB_STATE;
-    requestedSubMode         = 0;
-    changeSubMode            = FALSE;
+    testRequestedSubMode     = 0;
+    testChangeSubMode        = FALSE;
     broadcastModeIntervalCtr = DATA_PUBLISH_COUNTER_START_COUNT;
     isDeviceDefeatured       = FALSE;
     isBoostInstalled         = FALSE;
@@ -130,10 +132,15 @@
 
     // Any new mode requests?
     newMode = arbitrateModeRequest();   // Will return current mode if no pending requests
-    newMode = MODE_TRANSITION_TABLE[ currentMode ][ newMode ];
 
+    if ( isTestingActivated() != TRUE )
+    {
+        // If the test configuration is not enabled check for the legality of the transition request
+        newMode = MODE_TRANSITION_TABLE[ currentMode ][ newMode ];
+    }
+
     // Is requested new mode valid and legal at this time?
-    if ( ( newMode >= FP_MODE_NLEG ) && ( isTestingActivated() != TRUE ) )
+    if ( newMode >= FP_MODE_NLEG )
     {
         SET_ALARM_WITH_2_U32_DATA( ALARM_ID_FP_SOFTWARE_FAULT, FP_FAULT_ID_OP_MODES_ILLEGAL_MODE_TRANSITION_REQUESTED, newMode )
         newMode = currentMode;
@@ -149,34 +156,10 @@
 //        sendOperationStatusEvent();
     }
     // Is sub mode change request active?
-    if ( changeSubMode )
+    if ( testChangeSubMode )
     {
-        switch ( currentMode )
-        {
-            case FP_MODE_PGEN:
-                signalNewPreGenPSubMode( requestedSubMode );
-                break;
-
-            case FP_MODE_GENP:
-                signalNewGenPermeateSubMode( requestedSubMode );
-                break;
-
-            case FP_MODE_DPGP:
-                signalNewPreGenPDefeaturedSubMode( requestedSubMode );
-                break;
-
-            case FP_MODE_DEGP:
-                signalNewGenPDefeaturedSubMode( requestedSubMode );
-                break;
-
-            case FP_MODE_FAUL:
-            case FP_MODE_SERV:
-            case FP_MODE_INIT:
-            case FP_MODE_STAN:
-            default:
-                break;
-        }
-        changeSubMode = FALSE;
+        testChangeSubMode = FALSE;
+        requestNewFPOperationSubMode();
     }
 
     // Mode specific processing to be done continuously
@@ -260,21 +243,6 @@
 
 /*********************************************************************//**
  * @brief
- * The requestNewFPOperationSubMode function requests transition to a new
- * operation sub mode. The request will be arbitrated when the state machine
- * is next executed.
- * @details \b Inputs: none
- * @details \b Outputs: requestedSubMode, changeSubMode
- * @return none
- *************************************************************************/
-void requestNewFPOperationSubMode( U32 reqSubMode )
-{
-    requestedSubMode = reqSubMode;
-    changeSubMode = TRUE;
-}
-
-/*********************************************************************//**
- * @brief
  * The getCurrentFPOperationMode function gets the current operation mode.
  * @details \b Inputs: currentMode
  * @details \b Outputs: none
@@ -424,6 +392,84 @@
 
 /*********************************************************************//**
  * @brief
+ * The requestNewFPOperationSubMode function requests transition to a new
+ * operation sub mode.
+ * @details \b Inputs: none
+ * @details \b Outputs: none
+ * @return none
+ *************************************************************************/
+static void requestNewFPOperationSubMode( void )
+{
+    switch ( currentMode )
+    {
+        case FP_MODE_PGEN:
+            signalNewPreGenPSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_GENP:
+            signalNewGenPermeateSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_DPGP:
+            signalNewPreGenPDefeaturedSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_DEGP:
+            signalNewGenPDefeaturedSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_FAUL:
+        case FP_MODE_SERV:
+        case FP_MODE_INIT:
+        case FP_MODE_STAN:
+        default:
+            break;
+    }
+}
+
+/*********************************************************************//**
+ * @brief
+ * The validateSubModeChangeRequest function requests transition to a new
+ * operation sub mode.
+ * @details \b Inputs: none
+ * @details \b Outputs: none
+ * @return TRUE if request is legal, FALSE if not.
+ *************************************************************************/
+static BOOL validateSubModeChangeRequest( U32 reqSubMode )
+{
+    BOOL result = FALSE;
+
+    switch ( currentMode )
+    {
+        case FP_MODE_PGEN:
+            result = validatePreGenPChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_GENP:
+            result = validateGenPermeateChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_DPGP:
+            result = validatePreGenPDefeaturedChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_DEGP:
+            result = validateGenPDefeaturedChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_FAUL:
+        case FP_MODE_SERV:
+        case FP_MODE_INIT:
+        case FP_MODE_STAN:
+        default:
+            break;
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The setCurrentFPSubState function sets the current subState.
  * @details \b Inputs: none
  * @details \b Outputs: currentSubState
@@ -601,14 +647,26 @@
 
         if ( reqMode < NUM_OF_FP_MODES )
         {
-            requestNewFPOperationMode( reqMode );
+            // verify if the requested submode transition is possible
+            result = validateSubModeChangeRequest( reqSubMode );
 
-            // check to avoid repeated initialization if the requested sub mode matches with current sub mode
-            if ( requestedSubMode != currentSubMode )
+            // send the sub mode change request only if the requested transition is valid
+            if ( result )
             {
-                requestNewFPOperationSubMode(reqSubMode);
+                // request new operation mode and sub mode if the requested operation mode is not current mode
+                if ( currentMode != reqMode )
+                {
+                    requestNewFPOperationMode( reqMode );
+                    testRequestedSubMode = reqSubMode;
+                    testChangeSubMode = TRUE;
+                }
+                // request submode change only as the requested operation mode is current mode and requested sub mode is not current sub mode
+                else if ( currentSubMode != testRequestedSubMode )
+                {
+                    testRequestedSubMode = reqSubMode;
+                    testChangeSubMode = TRUE;
+                }
             }
-            result = TRUE;  // TODO confirm if this is correct
         }
     }