Apple's iPhone 5s boasts a Touch ID fingerprint sensor, which allows you to ditch your passcode in favour of your fingerprint. However, as with most technology, sometimes things can go wrong. Here, we take you through the troubleshooting steps so you know what to do if your fingerprint sensor isn't working. If you've already set up the fingerprint sensor and it's been working, then the chances are there's something you can do about it if it goes wrong. However, if it doesn't work from the moment you get your iPhone out of the box, you may want book a Genius appointment at the Apple Store to get them to take a look at it. It's possible that it's faulty and you'll need a replacement.