Index: firmware/App/Modes/FPModes/ModePreGenPermeateDefeatured.c
===================================================================
diff -u -r9f7c5de17f8e3d832da0888f138fb7602cc33a78 -r3e1af7cc2576e347ab8bdf2f400196b2301def07
--- firmware/App/Modes/FPModes/ModePreGenPermeateDefeatured.c	(.../ModePreGenPermeateDefeatured.c)	(revision 9f7c5de17f8e3d832da0888f138fb7602cc33a78)
+++ firmware/App/Modes/FPModes/ModePreGenPermeateDefeatured.c	(.../ModePreGenPermeateDefeatured.c)	(revision 3e1af7cc2576e347ab8bdf2f400196b2301def07)
@@ -7,8 +7,8 @@
 *
 * @file    ModePreGenPermeateDefeatured.c
 *
-* @author  (last)      “rkallala”
-* @date    (last)      15-Jan-2026
+* @author  (last)      Raghu Kallala
+* @date    (last)      31-Mar-2026
 *
 * @author  (original)  Michael Garthwaite
 * @date    (original)  08-Sep-2025
@@ -377,4 +377,71 @@
     return result;
 }
 
+/*********************************************************************//**
+ * @brief
+ * The testValidatePreGenPDefeaturedChangeReq function validate whether
+ * requested sub mode change is legal or not.
+ * @details \b Inputs: none
+ * @details \b Outputs: none
+ * @param newSubMode the enumerated sub state of the mode.
+ * @return TRUE if request is legal, FALSE if not.
+ *************************************************************************/
+BOOL testValidatePreGenPDefeaturedChangeReq( U32 newSubMode )
+{
+    BOOL result = FALSE;
+
+    if ( newSubMode < NUM_OF_FP_PRE_GENP_DEF_MODE_STATES )
+    {
+        switch ( newSubMode )
+        {
+            case FP_PRE_GENP_DEF_INLET_PRESSURE_CHECK:
+            case FP_PRE_GENP_DEF_FLUSH:
+                result = TRUE;
+                break;
+
+            // TODO change once pause state is implemented
+            case FP_PRE_GENP_DEF_PAUSED:
+            default:
+                break;
+        }
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testSignalNewPreGenPDefeaturedSubMode function requests transition
+ * to a new defeatured PreGen Permeate sub mode.
+ * @details \b Inputs: none
+ * @details \b Outputs: preGenPermeateDefState
+ * @param newSubMode the enumerated sub state of the mode.
+ * @return none
+ *************************************************************************/
+void testSignalNewPreGenPDefeaturedSubMode( U32 newSubMode )
+{
+    if ( newSubMode < NUM_OF_FP_PRE_GENP_DEF_MODE_STATES )
+    {
+        preGenPermeateDefState = (FP_PRE_GENP_DEF_MODE_STATE_T)newSubMode;
+        // handle the prerequisite if any
+        switch ( newSubMode )
+        {
+            // Any of these state require no special handling
+            case FP_PRE_GENP_DEF_INLET_PRESSURE_CHECK:
+                resetInletPressureCheckSignals();
+                break;
+
+            case FP_PRE_GENP_DEF_FLUSH:
+                resetFilterFlushDefSignals();
+                signalStartDefFilterFlush();
+                break;
+
+            case FP_PRE_GENP_DEF_PAUSED:
+            default:
+                break;
+        }
+        setModePreGenPDefTransition( preGenPermeateDefState );
+    }
+}
+
 /**@}*/