Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -rdd70052b03eeb284223a4aade8567a4acec63efb -r699c4f96ab672fb9db9ac218a5a00358dc68c2c6
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision dd70052b03eeb284223a4aade8567a4acec63efb)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 699c4f96ab672fb9db9ac218a5a00358dc68c2c6)
@@ -981,21 +981,23 @@
 
     // find expired messages pending ACK
     for ( i = 0; i < PENDING_ACK_LIST_SIZE; i++ )
-    {
+    {   // pending ACK expired?
         if ( ( TRUE == pendingAckList[ i ].used ) && ( TRUE == didTimeout( pendingAckList[ i ].timeStamp, MSG_NOT_ACKED_TIMEOUT_MS ) ) )
-        {
+        {   // if retries left, reset and resend pending message
             if ( pendingAckList[ i ].retries > 0 )
             {   // re-queue message for transmit
                 pendingAckList[ i ].retries--;
                 pendingAckList[ i ].timeStamp = getMSTimerCount();
                 addToCommBuffer( pendingAckList[ i ].channel, pendingAckList[ i ].msg, pendingAckList[ i ].msgSize );
-            }
+            }
+            // if no retries left, alarm
             else
             {
                 U16 msgID;
 
                 memcpy( &msgID, &pendingAckList[ i ].msg[ sizeof( U08 ) + sizeof( U16) ], sizeof( U16 ) );
-                SET_ALARM_WITH_1_U32_DATA( ALARM_ID_CAN_MESSAGE_NOT_ACKED, (U32)msgID );
+                SET_ALARM_WITH_1_U32_DATA( ALARM_ID_CAN_MESSAGE_NOT_ACKED, (U32)msgID );
+                pendingAckList[ i ].used = FALSE;  // take pending message off of list
             }
         }
     }