Q: touch ID failed

Try to "Reset All Settings" in General > Reset

please refer to http://support.apple.com/kb/HT5883 for more info on Touch ID

http://support.apple.com/kb/HT1212 Try this.

After I've replaced my Full cracked LCD, I got this MSG “Failed. Unable to complete Touch ID setup. Please go back and try again.”, I've tried Software Solutions (Reset, Erase All setting,..), nothing works, and than I got another New LCD I've tried it but still the same issue, it's like two hours searching for the main problem,what I found guys is each iPhone has an individual sensor (the home button), I mean you can't use a full screen replacement and put it directly on the phone what you gonna do is to take the sensor button from the cracked screen and place it into the new one, each sensor represent a specific iPhone (my experience was with iPhone 5s), so if the original home button is broken you will not be able to use fingerprints any more.
Thank you guys