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.

iPhone 5s review

How to fix iPhone 5s fingerprint sensor: clean it

The first port of call in fixing an unresponsive fingerprint scanner is to clean the Touch ID sensor. This takes a high resolution picture of the sub-epidermal layers of your skin to read your fingerprint and compare it to the fingerprint it has on file, so if there's dirt or grime on the Home button, the likelihood is your iPhone 5s will have difficulty confirming that you really are who you say you are.

You can clean the Home button with a lint-free cloth (like the kind you use to clean glasses or a tablet screen).

To find out more about how the Touch ID fingerprint scanner works, visit our Inside the iPhone 5s Touch ID scanner article.

How to fix iPhone 5s fingerprint sensor: update your iPhone

If cleaning the sensor doesn't help, it's worth checking that your iPhone is up to date. To check, go to Settings > General > Software Update.

Apple uses minor iOS 7 updates to fix bugs and make improvements to the software, to the fingerprint sensor technology could be part of those improvements. The latest iOS update was iOS 7.0.4.

How to position your finger correctly on iPhone 5s Touch ID

Apple advises that users should cover the Home button completely when using the fingerprint sensor. You should also make sure not to tap too quickly or press down too hard, and should keep your finger still while it's being scanned (this should only take a second or two).

Once you've got the hang of it it'll become second nature. (It did for us).

If you've done all these things and it's still not working, there are some more things you can try.

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How to enable Touch ID iPhone Unlock 

The first is to go to Settings > General > Touch ID & Passcode > Touch ID and make sure that iPhone Unlock is enabled (it'll be green if it is). If you want to use your fingerprint to make purchases in iTunes and the App Store, you can enable iTunes & App Store here too.

How to fix iPhone 5s fingerprint sensor: add more fingerprints

Another thing you'll benefit from is the ability to add more fingerprints. You can add up to five fingerprints to the iPhone 5s, and then you'll be able to use any one of those fingers to unlock the device (you don't specify a default).

To add more fingerprints, go to Settings > General > Touch ID & Passcode > Touch ID. You can then add a new fingerprint by following the steps in our how to set up Touch ID article.

How to fix iPhone 5s fingerprint sensor: re-register a fingerprint

If there's a particular finger that's already registered but isn't working, you can reenrol it. Go to Settings > General > Touch ID & Passcode > Touch ID > Edit. From here you can delete a fingerprint, then follow the instructions to add a new fingerprint.

To find the faulty fingerprint hold your finger over the scanner and see which of the recorded fingerprints are not highlighted.

How to fix iPhone 5s fingerprint sensor: clean your fingers

Your Home button should be squeaky clean but that doesn't mean your fingers are.

Apple advises that moisture, lotions, sweat, oils, cuts or dry skin can affect fingerprint recognition. It also claims that excercising, showering, swimming and cooking can reduce the chances of recognition (we wouldn't advise going without these activities, however).

If you've tried all of these things to no avail, then a trip to the Apple Store is in order. You can book an appointment with an Apple Genius by following this link.

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