Index: firmware/App/Controllers/DGInterface.c
===================================================================
diff -u -r1d07de4e970f54f2ae1786ef546cf5567df9ba8e -reb5370021e7e60c18732382a512886da0f9b276d
--- firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision 1d07de4e970f54f2ae1786ef546cf5567df9ba8e)
+++ firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision eb5370021e7e60c18732382a512886da0f9b276d)
@@ -550,6 +550,12 @@
 {
     if ( opMode < NUM_OF_DG_MODES )
     {
+        // reset POST passed flag if DG restarted or faulted or went to service mode
+        if ( ( opMode < DG_MODE_STAN ) && ( dgCurrentOpMode >= DG_MODE_STAN ) )
+        {
+            signalDGPOSTFinalResult( FALSE );
+        }
+        // update DG op mode and sub-mode
         dgCurrentOpMode = (DG_OP_MODE_T)opMode;
         dgSubMode = subMode;
     }
Index: firmware/App/Modes/ModeInitPOST.c
===================================================================
diff -u -r1d07de4e970f54f2ae1786ef546cf5567df9ba8e -reb5370021e7e60c18732382a512886da0f9b276d
--- firmware/App/Modes/ModeInitPOST.c	(.../ModeInitPOST.c)	(revision 1d07de4e970f54f2ae1786ef546cf5567df9ba8e)
+++ firmware/App/Modes/ModeInitPOST.c	(.../ModeInitPOST.c)	(revision eb5370021e7e60c18732382a512886da0f9b276d)
@@ -448,6 +448,18 @@
 
 /*********************************************************************//**
  * @brief
+ * The isDGPOSTPassed function determines whether all DG POST have passed.
+ * @details Inputs: postPassed
+ * @details Outputs: none
+ * @return true if all DG POST tests have passed, false if not
+ *************************************************************************/
+BOOL isDGPOSTPassed( void )
+{
+    return dgPOSTPassed;
+}
+
+/*********************************************************************//**
+ * @brief
  * The handlePOSTStatus function handles a status result returned by a
  * POST function.
  * @details Inputs: testStatus
Index: firmware/App/Modes/ModeInitPOST.h
===================================================================
diff -u -rf760ffc4b10556e5186e9ceb90294262063440ca -reb5370021e7e60c18732382a512886da0f9b276d
--- firmware/App/Modes/ModeInitPOST.h	(.../ModeInitPOST.h)	(revision f760ffc4b10556e5186e9ceb90294262063440ca)
+++ firmware/App/Modes/ModeInitPOST.h	(.../ModeInitPOST.h)	(revision eb5370021e7e60c18732382a512886da0f9b276d)
@@ -37,6 +37,7 @@
 U32  execInitAndPOSTMode( void );                                   // Execute the init. & POST mode state machine (call from OperationModes)
 BOOL isPOSTCompleted( void );                                       // Determine whether POST has completed yet
 BOOL isPOSTPassed( void );                                          // Determine whether POST has passed
+BOOL isDGPOSTPassed( void );                                        // Determine whether DG POST has passed
 void signalAlarmActionToInitAndPOSTMode( ALARM_ACTION_T action );   // Execute alarm action as appropriate for fault mode
 void signalUIPOSTFinalResult( BOOL passed );                        // Record UI POST result
 void signalDGPOSTFinalResult( BOOL passed );                        // Record DG POST result
Index: firmware/App/Modes/ModeStandby.c
===================================================================
diff -u -r19f13e67288117e7f81c1245a75cc6b5f8aaf899 -reb5370021e7e60c18732382a512886da0f9b276d
--- firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision 19f13e67288117e7f81c1245a75cc6b5f8aaf899)
+++ firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision eb5370021e7e60c18732382a512886da0f9b276d)
@@ -284,7 +284,7 @@
     REQUEST_REJECT_REASON_CODE_T rejReason = REQUEST_REJECT_REASON_NONE;
 
     // Verify HD is in standby mode waiting for treatment start request
-    if ( ( MODE_STAN != getCurrentOperationMode() ) || ( STANDBY_WAIT_FOR_TREATMENT_STATE != currentStandbyState ) )
+    if ( ( MODE_STAN != getCurrentOperationMode() ) || ( STANDBY_WAIT_FOR_TREATMENT_STATE != currentStandbyState ) || ( isPOSTPassed() != TRUE ) )
     {
         rejReason = REQUEST_REJECT_REASON_NOT_ALLOWED_IN_CURRENT_MODE;
     }
@@ -299,7 +299,7 @@
         rejReason = REQUEST_REJECT_REASON_DG_INCOMPATIBLE;
     }
     // Verify DG is not busy
-    else if ( ( DG_MODE_STAN != getDGOpMode() ) || ( DG_STANDBY_MODE_STATE_IDLE != getDGSubMode() ) )
+    else if ( ( DG_MODE_STAN != getDGOpMode() ) || ( DG_STANDBY_MODE_STATE_IDLE != getDGSubMode() ) || ( isDGPOSTPassed() != TRUE ) )
     {
         rejReason = REQUEST_REJECT_REASON_DG_NOT_IN_STANDBY_IDLE_STATE;
     }