Worried your Galaxy S5 might have a dead pixel on its display, or that its accelerometer isn’t working properly? You could take it to a Samsung Service Center, or you could use your handset’s hidden service menu to test all of its features yourself. Here’s how.

Accessing the service menu is super simple. Just open up your Galaxy S5’s Phone app, navigate to the keypad, then tap *#0*# (without spaces). You won’t need to press the call button; as soon as you hit that last hash the service mode will appear.

In here, you have the ability to test all kinds of things. Here’s a quick rundown of what each button does:

• Red, Green & Blue
  These buttons simply turn your display different colors so that you can detect dead pixels. It makes it much easier to find them than you could through normal use of your device.
• Receiver
  This button plays a loud noise through your Galaxy S5’s receiver (the speaker above its display) to ensure it’s working.
• Vibration
  This one’s pretty self-explanatory. Tap this to test your Galaxy S5’s vibration motor.
• Dimming
  This option tests your display’s ability to lower its own brightness. It presents three colors — red, green, and blue — and as you tap the screen the display will toggle between two brightness settings.
• Mega cam
  We’re not sure why this one has a fancy name, but it allows you to test your Galaxy S5’s rear-facing camera. This one’s particularly handy if you’re having camera problems when using the built-in Camera app, because it helps you identify whether it’s simply a bug or a corruption in the code, or whether there’s an actual hardware fault.
• Sensor
  This option allows you to test a whole bunch of your handset’s internal sensors (you’ll be surprised how many there are) — including its gyroscope, accelerometer, and proximity sensor. If you’re having problems playing games using the accelerometer and gyroscope, this will tell you whether it’s the game’s fault or a dodgy sensor.
• Touch
  If you’re having touchscreen problems, the Touch option allows you to test your display’s digitizer to ensure it’s picking up touch input properly. Follow the pattern onscreen with your finger — if any of the squares don’t like up when you go over them, you could have a dead spot.
• TSP Hovering
  Your Galaxy S5’s display is super sensitive to touch input; so much so that it picks up your finger before it’s even made contact with the display — that’s why you can use your phone with gloves on. TSP Hovering, like the Touch test, check your handset’s ability to accurately detect hovering fingertips.
• Sleep
  Surprise, surprise! This option tests your handset’s ability to enter sleep mode. We’re not quite sure why you’d ever need to do that.
• Speaker
  This test plays a song loudly to ensure your Galaxy S5’s speaker is working properly. It plays at maximum volume, so don’t try this one in bed while your wife’s asleep next to you. If you don’t hear anything after tapping this button, or the sound is quiet and muffled, you have a speaker problem.
• Sub key
  Having trouble with your handset’s capacitive back and multitasking buttons? Sub key lets you test them by turning your display snazzy colors as you tap them. Again, if the buttons work here but they’re not working under normal use, then you may have a software issue.
• Front cam
  Like the Mega cam test, this one lets you test your Galaxy S5’s front-facing camera.
• LED
  This test turns your phone’s LED light red, then green, then blue to ensure it’s working as it should.
• IR LED
  This one tests the infrared sensor built into the top edge of your device, however, since this is a service test and not a remote app, you’ll need a Samsung TV to use it.
• Low frequency
  If your speaker works, but doesn’t quite sound right, you can use this option to test its ability to output different frequencies, including 100Hz, 200Hz, and 300Hz.
• Barcode Emulator Test
  As it’s name suggests, this option lets you test your Galaxy S5’s ability to read different barcodes. We’d assume that if your cameras are working, then it should have issues reading barcodes, but for some reason this function has a test of its own.
• SensorHub Test
  Honestly, I’m not entirely sure what this one does, but it should make your screen go black and then tell you your handset has passed the test… whatever that test was for.
• Black
  Like the first three buttons, this option simply turns your display black, presumably to test its ability to turn off all pixels and ensure none of them are stuck.

While the service test isn’t really designed for end users, you can’t do any damage to your device in here, so don’t worry about playing around. It’s simply a handy way to check everything’s working as it should. It should work on other Samsung smartphones, too, so give it a try on yours.

• ViaAndroid Central