Hyundai Repair: hyundai, coolant temperature sensor, temperature reading

Question
first i need to know what is the cause of po118 code is and second i need to know why the car pulls to the left when i take off but go's strait when i let go of the gas

Answer
P0118 simply indicates an abnormal coolant temperature.  This could be due to overheating, a stuck open thermostat, or a problem with the coolant temperature sensor itself (or its wiring).

If you have the capability of accessing freeze frame data (a snapshot of the ECM data at the time the problem occurred), this will be key in helping you determine which of the above scenarios are possible.  For example, if the coolant temperature reading is so cold as to be not believable, you'll know you're looking at a problem with the sensor (or its wiring).  If the temperature is excessively high (typically around 250 degrees F or so), then the most likely scenario is that the engine was overheating.  If the temperature is warm but lower than operating temperature, then you should suspect the thermostat is stuck open.