I have a fiat Punto W reg 1.9 JTD ELX, its digital display keep on flashing all the time when it is running, though all the functions are working fine i.e Trip computer, Clock etc.
If its battery get a decent one....if proxy-alignment is required about £30-25.Personally I suspect the battery especially if its a old/cheap battery & obviously diesels need more amperage at start up.