To get my S4 mini to connect to Kies i needed these two pieces of info ...
To unlock the Dev Options menu, go to Settings -> About Device and scroll down to the "Build Number."
Now, tap on your "Build Number" five times, and you should see a toast notification pop up saying "Developer mode has been enabled."
Voilą! Back out of the About Device menu and you'll see Dev Options back where it belongs, so you can turn on USB Debugging and whatever else you want to.
Enable USB debugging mode on the phone.
Tap on Settings >> Developer options >> USB debugging mode.
it should be turned ON.
1. Turn off the handset.
2. Remove the battery and wait for 30 seconds.
3. Reinsert the battery and turn ON the device.
>> Turn OFF (Bluetooth, Wi-Fi and GPS) if turned ON.
>> Start a fresh connection between phone and the computer using compatible Samsung USB cable.
>> Try with different USB ports available on your computer.
I do not know if this will help you; hope it does