Index: firmware/App/Modes/ModeFault.c
===================================================================
diff -u -r6f2218c22e666aec059afbd60f3d0d268b305ad0 -rc137d3c7cb17b0364d745e10ff6dbd1901eb1baa
--- firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision 6f2218c22e666aec059afbd60f3d0d268b305ad0)
+++ firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision c137d3c7cb17b0364d745e10ff6dbd1901eb1baa)
@@ -1,17 +1,17 @@
 /**************************************************************************
 *
-* Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
+* Copyright (c) 2019-2021 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
+* @file    ModeFault.c
 *
-* @author (last) Sean Nash
-* @date (last) 24-Sep-2020
+* @author  (last)      Quang Nguyen
+* @date    (last)      29-Jun-2021
 *
-* @author (original) Dara Navaei
-* @date (original) 05-Nov-2019
+* @author  (original)  Dara Navaei
+* @date    (original)  05-Nov-2019
 *
 ***************************************************************************/
 
@@ -35,6 +35,9 @@
 
 // ********** private data **********
 
+// TODO expand this later
+static HD_FAULT_STATE_T faultState = HD_FAULT_STATE_START;          ///< Currently active fault state.
+
 // ********** private function prototypes **********
 
 /*********************************************************************//**
@@ -54,9 +57,9 @@
  * The transitionToFaultMode function prepares for transition to fault mode.
  * @details Inputs: none
  * @details Outputs:
- * @return none
+ * @return initial state
  *************************************************************************/
-void transitionToFaultMode( void )
+U32 transitionToFaultMode( void )
 {
     HD_OP_MODE_T previousOpMode = getPreviousOperationMode();
 
@@ -77,6 +80,8 @@
         collectTreatmentLogData();
         sendTreatmentLogDataToUI();
     }
+
+    return faultState;
 }
 
 /*********************************************************************//**
@@ -96,6 +101,7 @@
     signalDialInPumpHardStop();
     signalDialOutPumpHardStop();
     stopSyringePump();
+
     // Ensure all valves are in safe position
     setValveAirTrap( STATE_CLOSED );
     setValvePosition( VDI, VALVE_POSITION_C_CLOSE );
@@ -153,7 +159,7 @@
     button_state = stop;
 #endif
 
-    return 0;  // Fault mode has no sub-modes
+    return faultState;  // TODO expand the states later
 }
 
 /*********************************************************************//**