Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r965eb10d9407c25e8cf334623ad45e126cecee97 -rcf7e64c950aab8f40a16010991ae068e466e9ee9
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 965eb10d9407c25e8cf334623ad45e126cecee97)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision cf7e64c950aab8f40a16010991ae068e466e9ee9)
@@ -3660,4 +3660,70 @@
     return result;
 }
 
+/*********************************************************************//**
+* @brief
+* The handleUIServiceModeRequest function handles a request to enter service
+* mode.
+* @details Inputs: none
+* @details Outputs: message handled
+* @param message a pointer to the message to handle
+* @return none
+*************************************************************************/
+void handleUIServiceModeRequest( MESSAGE_T *message )
+{
+    BOOL status = FALSE;
+    DG_OP_MODE_T currentMode = getCurrentOperationMode();
+    REQUEST_REJECT_REASON_CODE_T reject;
+
+    if ( 0 == message->hdr.payloadLen )
+    {
+        if ( ( MODE_STAN == currentMode ) || ( MODE_FAUL == currentMode ) )
+        {
+            status = TRUE;
+            requestNewOperationMode( MODE_SERV );
+            reject = REQUEST_REJECT_REASON_NONE;
+        }
+        else
+        {
+            reject = REQUEST_REJECT_REASON_DG_NOT_IN_STANDBY_IDLE_STATE;
+        }
+    }
+    else
+    {
+        reject = REQUEST_REJECT_REASON_INVALID_REQUEST_FORMAT;
+    }
+
+    // Respond to request
+    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, status );
+    sendUIServiceModeResponse( status, (U32)reject );
+}
+
+/*********************************************************************//**
+ * @brief
+ * The sendUIServiceModeResponse function sends out the DG response to a
+ * UI request to go to service mode.
+ * @details Inputs: none
+ * @details Outputs: Service mode request response msg constructed and queued
+ * @param accepted TRUE if request was accepted, FALSE if not
+ * @param rejCode Reject reason code explaining why request was rejected
+ * @return none
+ *************************************************************************/
+void sendUIServiceModeResponse( BOOL accepted, U32 rejCode )
+{
+    MESSAGE_T msg;
+    U08 *payloadPtr = msg.payload;
+
+    // Create a message record
+    blankMessage( &msg );
+    msg.hdr.msgID = MSG_ID_DG_RESPONSE_SERVICE_MODE_REQUEST;
+    msg.hdr.payloadLen = sizeof( BOOL ) + sizeof( U32 );
+
+    memcpy( payloadPtr, &accepted, sizeof( BOOL ) );
+    payloadPtr += sizeof( BOOL );
+    memcpy( payloadPtr, &rejCode, sizeof( U32 ) );
+
+    // Serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
+    serializeMessage( msg, COMM_BUFFER_OUT_CAN_DG_2_UI, ACK_REQUIRED );
+}
+
 /**@}*/