I had one of those that I diagnosed right from the actual values displayed on the Pushbutton Controller. I think a description of the event was included in an article I wrote detailing diagnostics available through the PBC (pushbutton controller). It was in the Trade magazine "Import Car" April 2001.
It can be seen at this site:
The problem was the evaporator temp sensor. It was giving something like 155 deg and I think it was in Celcius.
I just tried the link and for some reason it isn't working. There are descriptions in these archives how to get actual values from the PBC. If you can't get through any of these, write me and I can enclose an attachment with the whole article.