We have had simular problems with late Doosan's where if they back fire crap gets on the TMAP sensors and this then throws a fault. There are software updates on some of these units which makes them less sensitive to this but you would need someone with software etc.
You also need to clear the code which you can do with a simular pedal dance to Mitsi's but not the same but I cant remember excactly how of the top of my head but I have got it written down some where.