Is it a 1.2 16v by anychance? If they can't get communication with the injection computer it can also be a feed or and earth as somebody mentioned or a multiplex fault. A friend in Renault also told me that sometimes when this happens they need to revert back to old clip(diagnostic) software as even thougn Renault say the new version should be able to do everything sometimes it can't read certain configurations.
I you have to replace it you could always consider going second hand you would need to get a key,
from another car but you are normally talking around £250 for this. I have a number for somebody who could provide you with this if need be.