Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -r2bb447181c2519690441d81f83563d17e0882ef2 -r85bfe5051e4d2bf67be39d394f96c075b4e52836
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 2bb447181c2519690441d81f83563d17e0882ef2)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 85bfe5051e4d2bf67be39d394f96c075b4e52836)
@@ -76,8 +76,9 @@
 static BOOL uiIsCommunicating = FALSE;              // has UI sent a message since last check
 static BOOL uiDidCommunicate = FALSE;               // has UI every sent a message
 
-static U32 sentCANPacketsCount = 0;
+static U32 sentCANPacketsCount = 0;  // TODO - debug - remove these two flags later
 static U32 compCANPacketsCount = 0;
+static CAN_MESSAGE_BOX_T pendingXmitMsgBox = 0;
 
 // ********** private function prototypes **********
 
@@ -250,6 +251,11 @@
  *************************************************************************/
 void handleCANMsgInterrupt( CAN_MESSAGE_BOX_T srcCANBox )
 {
+    if ( ( TRUE == isCANBoxForXmit( srcCANBox ) ) && ( srcCANBox != pendingXmitMsgBox ) )
+    {
+        srcCANBox = (CAN_MESSAGE_BOX_T)0;
+    }
+
     // message interrupt is for a transmit message box?
     if ( TRUE == isCANBoxForXmit( srcCANBox ) )
     {
@@ -500,8 +506,10 @@
         if ( dataSize == CAN_MESSAGE_PAYLOAD_SIZE )
         {
             signalCANXmitsInitiated();
+            pendingXmitMsgBox = mBox;
             if ( canTransmit( canREG1, mBox, data ) == 0 )
             {
+                signalCANXmitsCompleted();
                 // TODO - shouldn't get here, but let's see if we do
                 SET_ALARM_WITH_1_U32_DATA( ALARM_ID_SOFTWARE_FAULT, (U32)mBox )
             }