Index: firmware/App/Modes/ModeFault.c
===================================================================
diff -u -r200dfbd12ee14a4dbe5ee1daaece7bfce9e8a104 -rae3a2d3b6952e59cdf469d48e9f4c26574564eff
--- firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision 200dfbd12ee14a4dbe5ee1daaece7bfce9e8a104)
+++ firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision ae3a2d3b6952e59cdf469d48e9f4c26574564eff)
@@ -1,26 +1,28 @@
 /**************************************************************************
 *
-* Copyright (c) 2024-2024 Diality Inc. - All Rights Reserved.
+* Copyright (c) 2024-2026 Diality Inc. - All Rights Reserved.
 *
 * THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 * WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 * @file    ModeFault.c
 *
-* @author  (last)      Vinayakam Mani
-* @date    (last)      05-Aug-2024
+* @author  (last)      Raghu Kallala
+* @date    (last)      22-Apr-2026
 *
 * @author  (original)  Vinayakam Mani
-* @date    (original)  05-Aug-2024
+* @date    (original)  07-Aug-2024
 *
 ***************************************************************************/
 
+#include "BalancingChamber.h"
 #include "ConcentratePumps.h"
 #include "DialysatePumps.h"
 #include "Heaters.h"
 #include "ModeFault.h"
 #include "Messaging.h"
 #include "OperationModes.h"
+#include "RinsePump.h"
 #include "SafetyShutdown.h"
 #include "Utilities.h"
 #include "Valves.h"
@@ -74,6 +76,8 @@
 {
     initFaultMode();
     setCurrentSubState( NO_SUB_STATE );
+    // Deactivate Balancing Chamber Switching
+    requestBalChamberSwitching( FALSE );
     // Publish POST failure status to UI if fault triggered in Init/POST mode
     if ( DD_MODE_INIT == getPreviousOperationMode() )
     {
@@ -188,25 +192,19 @@
     setValveStateDelayed( D40_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     setValveStateDelayed( D47_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     setValveStateDelayed( D3_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
-    setValveStateDelayed( DD_M4_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
 
     // De-energize Balancing chamber and Ultrafiltration valves
     for ( i = FIRST_BC_VALVE; i <= LAST_BC_VALVE; i++ )
     {
         setValveStateDelayed( (DD_VALVES_T)i, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     }
 
-    // TODO: To be removed once HDD clean up is done
-    for ( i = FIRST_UF_VALVE; i <= FIRST_UF_VALVE; i++ )
-    {
-        setValveStateDelayed( (DD_VALVES_T)i, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
-    }
-
     requestConcentratePumpOff( D11_PUMP, parkPumps );
     requestConcentratePumpOff( D10_PUMP, parkPumps );
     requestConcentratePumpOff( D76_PUMP, parkPumps );
     signalDialysatePumpHardStop( D12_PUMP );
     signalDialysatePumpHardStop( D48_PUMP );
+    setRinsePumpState( RINSE_PUMP_STATE_OFF );
     stopHeater( D5_HEAT );
     stopHeater( D45_HEAT );
 }
@@ -223,8 +221,6 @@
  *************************************************************************/
 void deenergizeActuatorsWithDrainEnabled( BOOL parkPumps )
 {
-    U32 i;
-
     // Energize drain and spent balancing chamber valves to relieve the pressure.
     setValveState( D53_VALV, VALVE_STATE_OPEN );
     setValveState( D23_VALV, VALVE_STATE_OPEN );
@@ -245,26 +241,19 @@
     setValveStateDelayed( D40_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     setValveStateDelayed( D47_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     setValveStateDelayed( D3_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
-    setValveStateDelayed( DD_M4_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
 
     // De-energize portion of balancing chamber valves.
     setValveStateDelayed( D19_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     setValveStateDelayed( D20_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     setValveStateDelayed( D21_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
     setValveStateDelayed( D22_VALV, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
 
-    // TODO: To be removed once HDD clean up is done
-    // De-energize Ultrafiltration valves
-    for ( i = FIRST_UF_VALVE; i <= FIRST_UF_VALVE; i++ )
-    {
-        setValveStateDelayed( (DD_VALVES_T)i, VALVE_STATE_CLOSED, DELAY_VALVE_MS );
-    }
-
     requestConcentratePumpOff( D11_PUMP, parkPumps );
     requestConcentratePumpOff( D10_PUMP, parkPumps );
     requestConcentratePumpOff( D76_PUMP, parkPumps );
     signalDialysatePumpHardStop( D12_PUMP );
     signalDialysatePumpHardStop( D48_PUMP );
+    setRinsePumpState( RINSE_PUMP_STATE_OFF );
     stopHeater( D5_HEAT );
     stopHeater( D45_HEAT );
 }
@@ -395,4 +384,68 @@
     return state;
 }
 
+
+/*************************************************************************
+ *                       TEST SUPPORT FUNCTIONS
+ *************************************************************************/
+
+
+/*********************************************************************//**
+ * @brief
+ * The testValidateDDFaultChangeReq function validate whether request
+ * operation sub mode 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 testValidateDDFaultChangeReq( U32 newSubMode )
+{
+    BOOL result = FALSE;
+
+    if ( newSubMode < NUM_OF_DD_FAULT_STATES )
+    {
+        switch ( newSubMode )
+        {
+            case DD_FAULT_STATE_START:
+            case DD_FAULT_DEENERGIZED_STATE:
+            case DD_FAULT_ENERGIZED_STATE:
+                result = TRUE;
+                break;
+
+            default:
+                break;
+        }
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testSignalNewDDFaultSubMode function request transition to a
+ * new operation sub mode.
+ * @details \b Inputs: none
+ * @details \b Outputs: faultState
+ * @param newSubMode the enumerated sub state of the mode
+ * @return none
+ *************************************************************************/
+void testSignalNewDDFaultSubMode( U32 newSubMode )
+{
+    if ( newSubMode < NUM_OF_DD_FAULT_STATES )
+    {
+        faultState = (DD_FAULT_STATE_T)newSubMode;
+
+        switch ( newSubMode )
+        {
+            // Any of these state require no special handling
+            case DD_FAULT_STATE_START:
+            case DD_FAULT_DEENERGIZED_STATE:
+            case DD_FAULT_ENERGIZED_STATE:
+            default:
+                break;
+        }
+    }
+}
+
 /**@}*/