I posted my experience with this an had
some dialog with c4c5specialist and others. If you search for it (5/2001?)under the grandstand I think you will find the posted information useful. The warning has since gone away in my case.
I had a similar problem with my 01 Z. Took it to the dealer and he put in a new alternator. It was OK for a couple of hundred miles and then it started the Charge fault warning DIC again. Took it back and he installed another new alternator, again, and he found a loose connection. So far so good. It only stayed overnight both times. Since it's a weekend driver it wasn't to much of a pain however it was annoying. The service tech was in communication with Bowling Green Engineers about the problem because they had another C5 coupe in the shop with the same problem. We are not alone.
As for the CSF, I can only relate what I have experienced.
After dealing with many 97-01 on this issue, better than 60% of the cases I have traced to either bad batterys, loose grounds, or incorrect control of the alternator, by the PCM.
Usually, you will find a code, 1637 or 1638, if there is a confirmed issue with the PCM or the alternator.
Anything else, it is usually bad connections.
Something to consider, c4c5