Why isn't outdoor temperature displayed?

Try cleaning the outdoor thermometer transmitter unit by opening it up enough to spray compressed air (Ultra Duster or similar) on the temperature sensor. It fixed the hh.h error for me.

Have you changed the batteries on the outside sender unit?

Scroll through the digital display used to display trip distance, until it displays the outdoor air temperature.
Read more: How to Change Ford Focus Temperature Display to Celsius ' eHow.com http://www.ehow.com/how_5989096_change-focus-temperature-display-celsius.html#ixzz2Nd8mOf00

E221 is an indication that the out side temperature sensor is faulty,
this could mean it's open circuit (no resistance) sensing temperature or could be it has came loose on outdoor pcb (circuit board The E242 refers to a fault code, test temperature sensor and replace and you should be problem solved
see photos attached for help in testing the sensor

After replacing the transmitter batteries several times, I tried replacing the clock batteries. They must have been getting low. Once I put in new batteries in the clock it worked fine. Good Luck.