Index: firmware/App/Modes/ModeGenDialysate.c
===================================================================
diff -u -r6e36d2fd90b130f540494f4128951d81e7dc5ed5 -rde4b330865ad6f9966c76f3b335d5b3966f8a1b2
--- firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
+++ firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision de4b330865ad6f9966c76f3b335d5b3966f8a1b2)
@@ -57,6 +57,7 @@
 static OVERRIDE_F32_T targetHydChamberFluidTemp;                                            ///< Target hydraulics chamber fluid temperature.
 static OVERRIDE_U32_T isDialDeliveryInProgress;                                             ///< To indicate dialysate started delivering to dialyzer for treatment (overrideable)
 static OVERRIDE_U32_T isDialysateGoodtoDeliver;                                             ///< Flag indicating whether ready to deliver dialysate or not.
+static OVERRIDE_U32_T pendingStopDDGenDialRequest;                                          ///< Flag indicating TD has requested DD stop the generate dialysate (Overridable).
 static U32 genDialysateDataPublicationTimerCounter;                                         ///< Used to schedule generate dialysate data publication to CAN bus.
 static OVERRIDE_U32_T genDialysateDataPublishInterval;                                      ///< Generate dialysate mode data publish interval.
 static F32 lastDialTargetTemperatureSet;                                                    ///< last dialysate target temperature set for heater control
@@ -95,6 +96,10 @@
     isDialDeliveryInProgress.ovData             = FALSE;
     isDialDeliveryInProgress.ovInitData         = FALSE;
     isDialDeliveryInProgress.override           = OVERRIDE_RESET;
+    pendingStopDDGenDialRequest.data            = FALSE;
+    pendingStopDDGenDialRequest.ovData          = FALSE;
+    pendingStopDDGenDialRequest.ovInitData      = FALSE;
+    pendingStopDDGenDialRequest.override        = OVERRIDE_RESET;
     genDialysateDataPublishInterval.data        = GEN_DIALYSATE_DATA_PUBLISH_INTERVAL;
     genDialysateDataPublishInterval.ovData      = GEN_DIALYSATE_DATA_PUBLISH_INTERVAL;
     genDialysateDataPublishInterval.ovInitData  = 0;
@@ -233,13 +238,20 @@
 /*********************************************************************//**
  * @brief
  * The execGenDialysateMode function executes the Gen dialysate mode state machine.
- * @details \b Inputs: none
+ * @details \b Inputs: pendingStopDDGenDialRequest,genDialysateState
  * @details \b Outputs: Gen dialysate mode state machine executed
  * @details \b Alarm: ALARM_ID_DD_SOFTWARE_FAULT when wrong gen dialysate state invoked.
  * @return current state.
  *************************************************************************/
 U32 execGenDialysateMode( void )
 {
+    //TODO: Transition to post gen dialysate then standby.
+    if ( TRUE == getU32OverrideValue( &pendingStopDDGenDialRequest ) )
+    {
+        pendingStopDDGenDialRequest.data = FALSE;
+        requestNewOperationMode( DD_MODE_STAN );
+    }
+
     // Continuous water inlet pressure check
     if ( genDialysateState != DD_GEND_DIALYSATE_DELIVERY_PAUSE )
     {
@@ -414,18 +426,19 @@
  * The requestDDGenDialyasteStop function handles an TD request to stop
  * generation dialysis mode.
  * @details \b Inputs: Generation dialysate mode / state
- * @details \b Outputs: mode transition
+ * @details \b Outputs: mode pendingStopDDGenDialRequest
  * @return TRUE if request accepted, FALSE if not.
  *************************************************************************/
 BOOL requestDDGenDialyasteStop( void )
 {
-    BOOL status = TRUE;
+    BOOL status = FALSE;
 
-    //TODO: Transition to post gen dialysate and standby
+    if ( DD_MODE_GEND == getCurrentOperationMode() )
+    {
+        pendingStopDDGenDialRequest.data = TRUE;
+        status = TRUE;
+    }
 
-    // Transition to mode standby
-    requestNewOperationMode( DD_MODE_STAN );
-
     return status;
 }
 
@@ -665,6 +678,24 @@
 
 /*********************************************************************//**
  * @brief
+ * The testDDstopGenDialysateOverride function sets the override value
+ * to stop the gen dialysate operation mode.
+ * @details Inputs: pendingStopDDGenDialRequest
+ * @details Outputs: pendingStopDDGenDialRequest
+ * @param message Override message from Dialin which includes the flag
+ * to override the operation mode.
+ * @return TRUE if override successful, FALSE if not
+ *************************************************************************/
+BOOL testDDstopGenDialysateOverride( MESSAGE_T *message )
+{
+    BOOL result = u32Override( message, &pendingStopDDGenDialRequest, FALSE, TRUE );
+
+    return result;
+}
+
+
+/*********************************************************************//**
+ * @brief
  * The testGenDExecStateOverride function sets the Gen dialysate execution state
  * machine to given state.
  * @details \b Inputs: tester logged in, execStateSet
Index: firmware/App/Modes/ModeGenDialysate.h
===================================================================
diff -u -r6e36d2fd90b130f540494f4128951d81e7dc5ed5 -rde4b330865ad6f9966c76f3b335d5b3966f8a1b2
--- firmware/App/Modes/ModeGenDialysate.h	(.../ModeGenDialysate.h)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
+++ firmware/App/Modes/ModeGenDialysate.h	(.../ModeGenDialysate.h)	(revision de4b330865ad6f9966c76f3b335d5b3966f8a1b2)
@@ -63,6 +63,7 @@
 BOOL testDialGoodToDeliverStatusOverride( MESSAGE_T *message );             // To override the dialysate good to deliver status flag
 BOOL testGenDHydChamberFluidTempOverride( MESSAGE_T *message );             // Override the hydraulics chamber fluid temperature
 BOOL testGenDExecStateOverride( MESSAGE_T *message );                       // Override the Gen dialysate execution state
+BOOL testDDstopGenDialysateOverride( MESSAGE_T *message );                  // Override the stop gen dialysate request
 
 /**@}*/
 
Index: firmware/App/Modes/ModePreGenDialysate.c
===================================================================
diff -u -r6e36d2fd90b130f540494f4128951d81e7dc5ed5 -rde4b330865ad6f9966c76f3b335d5b3966f8a1b2
--- firmware/App/Modes/ModePreGenDialysate.c	(.../ModePreGenDialysate.c)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
+++ firmware/App/Modes/ModePreGenDialysate.c	(.../ModePreGenDialysate.c)	(revision de4b330865ad6f9966c76f3b335d5b3966f8a1b2)
@@ -40,6 +40,7 @@
 
 static DD_PRE_GEN_DAILYSATE_STATE_T preGenDialysateState;                   ///< Currently active pre-gen dialysate state.
 static OVERRIDE_U32_T pendingStartDDGenDialRequest;                         ///< Flag indicating TD has requested DD start the generation dialysate request(Overridable).
+static OVERRIDE_U32_T pendingStopDDPreGenDialRequest;                       ///< Flag indicating TD has requested DD stop the pre generation dialysate (Overridable).
 static U32 preGenDialysatePublishTimerCounter;                              ///< Pre-Gen Dialysate data broadcast timer counter used to schedule when to transmit data.
 static OVERRIDE_U32_T preGenDialysateModePublishInterval;                   ///< Interval (in task intervals) at which to publish pre-gen dialysate mode data to CAN bus.
 
@@ -63,6 +64,10 @@
     pendingStartDDGenDialRequest.ovData             = FALSE;
     pendingStartDDGenDialRequest.ovInitData         = FALSE;
     pendingStartDDGenDialRequest.override           = OVERRIDE_RESET;
+    pendingStopDDPreGenDialRequest.data             = FALSE;
+    pendingStopDDPreGenDialRequest.ovData           = FALSE;
+    pendingStopDDPreGenDialRequest.ovInitData       = FALSE;
+    pendingStopDDPreGenDialRequest.override         = OVERRIDE_RESET;
     preGenDialysateModePublishInterval.data         = PRE_GEN_DIALYSATE_DATA_PUB_INTERVAL;
     preGenDialysateModePublishInterval.ovData       = PRE_GEN_DIALYSATE_DATA_PUB_INTERVAL;
     preGenDialysateModePublishInterval.ovInitData   = 0;
@@ -105,6 +110,12 @@
         pendingStartDDGenDialRequest.data = FALSE;
         requestNewOperationMode( DD_MODE_GEND );
     }
+    //TODO: Transition to post gen dialysate if concentrate priming has been started
+    if ( TRUE == getU32OverrideValue( &pendingStopDDPreGenDialRequest ) )
+    {
+        pendingStopDDPreGenDialRequest.data = FALSE;
+        requestNewOperationMode( DD_MODE_STAN );
+    }
 
     // execute current pre-gen dialysate state
     switch ( preGenDialysateState )
@@ -166,21 +177,16 @@
  * The requestDDPreGenStop function handles an TD request to stop
  * pre-generation dialysis mode.
  * @details \b Inputs: Pre generation dialysate mode / state
- * @details \b Outputs: mode transition
+ * @details \b Outputs: pendingStopDDPreGenDialRequest
  * @return TRUE if request accepted, FALSE if not.
  *************************************************************************/
 BOOL requestDDPreGenStop( void )
 {
     BOOL status = FALSE;
 
-    //TODO: Transition to post gen dialysate if concentrate priming has been started
-
-    //TODO: Tranistion to standby if concentrate priming is not yet started
     if ( DD_MODE_PREG == getCurrentOperationMode() )
     {
-        // Transition to mode standby
-        requestNewOperationMode( DD_MODE_STAN );
-
+        pendingStopDDPreGenDialRequest.data = TRUE;
         status = TRUE;
     }
 
@@ -267,4 +273,21 @@
     return result;
 }
 
+/*********************************************************************//**
+ * @brief
+ * The testDDstopPreGenDialysateOverride function sets the override value
+ * to stop the pre gen dialysate operation mode.
+ * @details Inputs: pendingStopDDPreGenDialRequest
+ * @details Outputs: pendingStopDDPreGenDialRequest
+ * @param message Override message from Dialin which includes the flag
+ * to override the operation mode.
+ * @return TRUE if override successful, FALSE if not
+ *************************************************************************/
+BOOL testDDstopPreGenDialysateOverride( MESSAGE_T *message )
+{
+    BOOL result = u32Override( message, &pendingStopDDPreGenDialRequest, FALSE, TRUE );
+
+    return result;
+}
+
 /**@}*/
Index: firmware/App/Modes/ModePreGenDialysate.h
===================================================================
diff -u -r6e36d2fd90b130f540494f4128951d81e7dc5ed5 -rde4b330865ad6f9966c76f3b335d5b3966f8a1b2
--- firmware/App/Modes/ModePreGenDialysate.h	(.../ModePreGenDialysate.h)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
+++ firmware/App/Modes/ModePreGenDialysate.h	(.../ModePreGenDialysate.h)	(revision de4b330865ad6f9966c76f3b335d5b3966f8a1b2)
@@ -48,6 +48,7 @@
 
 BOOL testDDPreGenDialysateDataPublishIntervalOverride( MESSAGE_T *message );    // pre-gen dialysate publish override request
 BOOL testDDstartGenDialysateOverride( MESSAGE_T *message );                     // start gen dialysate override request
+BOOL testDDstopPreGenDialysateOverride( MESSAGE_T *message );                   // stop the pregen dialysate override request
 
 /**@}*/
 
Index: firmware/App/Services/Messaging.c
===================================================================
diff -u -r724b64673b719eaac10b0c9dd839ad9675274911 -rde4b330865ad6f9966c76f3b335d5b3966f8a1b2
--- firmware/App/Services/Messaging.c	(.../Messaging.c)	(revision 724b64673b719eaac10b0c9dd839ad9675274911)
+++ firmware/App/Services/Messaging.c	(.../Messaging.c)	(revision de4b330865ad6f9966c76f3b335d5b3966f8a1b2)
@@ -153,6 +153,8 @@
     MSG_ID_DD_POST_GEND_MODE_DATA_PUBLISH_OVERRIDE_REQUEST,
     MSG_ID_DD_START_PRE_GEN_DIALYSATE_MODE_OVERRIDE_REQUEST,                          //65
     MSG_ID_DD_PRE_GEN_DIALYSATE_REQUEST_DATA,
+    MSG_ID_DD_STOP_PRE_GEN_DIALYSATE_MODE_OVERRIDE_REQUEST,
+    MSG_ID_DD_STOP_GEN_DIALYSATE_MODE_OVERRIDE_REQUEST,
 #ifdef __PUMPTEST__
     MSG_ID_DD_PISTON_PUMP_DATA_PUBLISH_OVERRIDE_REQUEST,
     MSG_ID_DD_PISTON_PUMP_START_STOP_OVERRIDE_REQUEST,
@@ -228,6 +230,8 @@
     &testDDPostGenDialysateDataPublishIntervalOverride,
     &testDDstartPreGenDialysateOverride,                                              //65
     &handlePreGenDialysateRequestMsg,
+    &testDDstopPreGenDialysateOverride,
+    &testDDstopGenDialysateOverride,
 #ifdef __PUMPTEST__
     &testDDPistonPumpControlDataPublishIntervalOverride,
     &testDDPistonPumpStartStopOverride,