Samsung Galaxy phones have two built-in ways to test hardware: the hidden *#0*# test menu and the diagnostics in the Samsung Members app. Here is how to use both, what each test checks, and how to test a Galaxy phone that has the menus blocked.
Samsung hidden test menu (*#0*#)
- Open the Phone app and go to the keypad.
- Dial *#0*#. A grid of test buttons opens straight away, with no call button needed.
- Tap Red, Green and Blue for dead pixels, Touch for dead zones, Receiver and Speaker for audio, Vibration, Sensor and the cameras.
- Press the Back button twice to leave a test.
On many US carrier models (Verizon, AT&T, T-Mobile) the code is blocked and nothing happens. Use Samsung Members or the free browser test below instead.
*#0*# not working? What to try
- Type the code in Samsung’s own Phone app. If Google Phone or another dialer is set as your default, the code may do nothing.
- Don’t press the call button. The menu opens as soon as you type the last #. A Connection problem or invalid MMI code message means the code was sent to the network instead; clear the keypad and type it again.
- Many US carrier models (Verizon, AT&T, T-Mobile), some other regions and work phones managed by an employer block the menu completely.
- On One UI 6 and later, some users report that Auto Blocker stops the code. Try turning it off in Settings › Security and privacy › Auto Blocker, dial the code, then turn it back on.
- Use Samsung Members › Support › Phone diagnostics instead, which runs the same kind of tests on any Galaxy.
- Or open mxmob.com/check in Samsung Internet or Chrome. It needs no code and tests the screen, touch, speakers, microphone, cameras, sensors and more.
Samsung Members diagnostics
- Open Samsung Members (install it from the Galaxy Store or Play Store if it’s missing).
- Tap Support, then Phone diagnostics.
- Tap Test all, or pick single tests such as Battery status, Touch screen, Wi-Fi or Cameras.
Check battery health
- In Samsung Members › Phone diagnostics, run Battery status. Normal means healthy; Weak or Bad means the battery should be replaced.
- On newer One UI versions, also check Settings › Battery › Battery information for the charge cycle count and capacity.
Before a repair: Maintenance mode
Turn on Settings › Device care › Maintenance mode before handing a Galaxy phone to a repair shop. It hides your photos, messages and accounts while the technician tests the phone.
Test the parts built-in tools miss
Manufacturer diagnostics check that hardware is connected, but they rarely test everything you use. The MxMob phone diagnostic runs in the browser and checks every touch zone, left and right speakers, each camera lens, GPS accuracy, real Wi-Fi speed and more, then gives you a shareable report. Buying used? Follow the used phone checklist.
Diagnostic guides for other brands
Frequently asked questions
Why does *#0*# not work on my Samsung?
Usually because the carrier blocks it, which is common on Verizon, AT&T and T-Mobile models. It also fails if you dial it from Google Phone instead of Samsung’s Phone app, or press call (which shows “invalid MMI code”). Use Samsung Members › Support › Phone diagnostics instead, or open mxmob.com/check in Chrome or Samsung Internet.
Is the Samsung *#0*# test safe?
Yes. It only runs hardware tests and doesn’t change settings or delete data. Leave each test with the Back button. Avoid other unknown codes, some of which open settings that can affect the phone.
How do I check a used Samsung phone before buying?
Dial *#06# and check the IMEI isn’t blacklisted, run *#0*# or the MxMob browser diagnostic, check battery status in Samsung Members, and make sure the seller has removed their Samsung and Google accounts.