After contacting Electrolux support, I finally found an answer. It appears that Sf stands for Sabbath Failure … I have no idea how that got activated but my best guess would be when some water went on the touchpad and somehow activated the Sabbath Feature. This happened when my fingers did not even touch the unit! … The unit remembers that was set to be in Sabbath mode which explains why the rebooting did not help.
A simple solution would be to:
HOLD the central +(hi) and –(lo) buttons together at the same time until it exits the Sabbath Failure
Hope this helped somebody as I figure somebody will eventually google “Sf error code” and then can find this answer. (Also in the manual on page 41-42)
More info on the Sabbath Feature @ http://www.star-k.org
Cheers!