Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r7c84f3bce2c16c4256113c6dae208bcb7bb15825 -r94d39c4d2f4f24c172785903b9d715583ab496b9
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 7c84f3bce2c16c4256113c6dae208bcb7bb15825)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 94d39c4d2f4f24c172785903b9d715583ab496b9)
@@ -1124,12 +1124,20 @@
     DG_CMD_RESPONSE_T dgCmdResp;
     DG_OP_MODE_T dgOpMode = getDGOpMode();
 
-
-    if ( ( TRUE == getDGCommandResponse( DG_CMD_START_FILL, &dgCmdResp ) ) && ( DG_CMD_REQUEST_REJECT_REASON_INVALID_MODE == dgCmdResp.rejectCode ) )
+    // handle fill command response from DG
+    if ( TRUE == getDGCommandResponse( DG_CMD_START_FILL, &dgCmdResp ) )
     {
-        state = PRE_TREATMENT_RESERVOIR_MGMT_START_FILL_STATE;
+        if ( DG_CMD_REQUEST_REJECT_REASON_INVALID_MODE == dgCmdResp.rejectCode )
+        {
+            state = PRE_TREATMENT_RESERVOIR_MGMT_START_FILL_STATE;
+        }
+        else if ( dgCmdResp.rejectCode != DG_CMD_REQUEST_REJECT_REASON_NONE )
+        {
+            // TODO - s/w fault
+        }
     }
 
+    // wait for DG to begin filling before moving on to next state
     if ( DG_MODE_FILL == dgOpMode )
     {
         state = PRE_TREATMENT_RESERVOIR_MGMT_FILL_COMPLETE_STATE;