I was working on flashing my brand new never-activated S3 and became across the same issue with DFS not recognizing my S3. Here is my 100% working solution!!!
It is working with Note 3 too Step By Step. Instructions. 1. Put your S3 out of DIAG MODE, ---DIAL##3424# -Select PDA, MTP + ADB. Then press back button all the way to homescreen. 2. Reboot phone. 3. Once your phone is back, put your S3 in DIAG MODE again. ----DIAL ##3424# Select CDMA MODEM, DM+MODEM+ADB. Then press back button all the way to homescreen. Plug it in, give it a second. And tada, DFS detects your S3 as an online device. I'm guessing Samsung limited the number of times you can plug in your phone and read/write programming settings, to 1 per boo