Where is the temperature control sensor

What reading is determining that the sensor has failed? A trouble code that was retrieved maybe at a parts store? The code retrieved, if so, will pertain to a related system but not a specific component. It is true that the sensor may be the cause of failure, but it's by no means the only possible cause. The cylinder head temperature sensor on the 2011 Focus is directly at the top of the valve cover between cylinders two and three.