According to variety.com, although the writers may be back in front of the computers, Fox, which airs  has Terminator: Sarah Connor Chronicles, decided not to order any new episode orders for any of their serialized series this year as viewers might have difficulty getting back into the swing of things.

For the currently swinging mid-season series Sarah Connor Chronicles, this means that no additional episodes will be shot for this television season. Provided the current ratings remain steady, Sarah and her Chronicles are a likely contender to return next season.


Sarah Connor Chronicles already has nine episodes in the can, of which five have aired.

Remaining episodes are:
1.6 Dungeons & Dragons,
1.7 The Demon Hand
1.8 Vick's Chip
1.9 The Man Comes Around, which has been described as a cliff hanger.

Sources
http://www.variety.com/VR1117980756.html
http://www.tv.com/terminator-the-sarah-connor-chronicles/show/68708/episode_listings.html?om_act=convert&om_clk=episodessh&tag=episodes;more