The P0117 means your Engine Coolant Temperature Sensor is not functioning as it should. I would check all connections, maybe you unplugged the sensor and didn't plug it back in.
If the problem isn't in wiring, then you will have to replace the sensor. I understand it is a fairly cheap part and a fairly easy install. The sensor is located somewhere behind the alternator.
Here are the results when I searched "P0117" on NASIOC. I didn't wade through every thread, but I would if I were you.