EPS light issue

My smart is in cold, snowy environment. EPS light is long on, steering wheel is heavy in some turning. Mechanic friend ran computer with it and could not get signal (?) or reset (?) or read full data (?) of the sensor. Could be a bad sensor? I hesitate to throw a ton of money to fix it, given it seems to only mean an irresponsive power steering and having EPS off. Anyone had experience with such failure? If it is not a sensor issues, what can it be? How would the fixing be and how much is it?