If i get a code C0205 for my escalade cadillac 2002 what part needs to be replaced. The whole care feels loose.

Question

I own a 2002 cadillac escalad. It has 95,000 miles on it and for the past 6 months i feel the steering has gotten looser and looser. To much play in steering wheel. I also feel the front end is loose, and squecky.
I have to drive a long distance and am a female who knows not to much about cars. My nephew would fix it since he knows a lot about cars but we dont know what part to replace since it gives us a code C0205 but that doesnt pin poin the part only tells us its the steerign wheel psoition sensor circuit.
What can you sugest. I dont want to bring it to the dealer and the automechanic that we took the car to said he didnt have the cadilac coder so he used the GMC but that was all he could come up with. Help!!!! I have to drive it to school 2 hours away from home 3x a week and I dont feel safe. Please help. thank you sooooo much!
Thank you for your time. 8/28/2012