Android testing guide

Built-in diagnostics by brand

There is no one code for every Android phone. Use what exists for the brand, and fall back to the manual tests in the next section if it does not work.

1. 1Samsung: open the Samsung Members app > Support > Diagnostics. This is Samsung's official test. The code *#0*# is community-reported and may not work.
2. 2Xiaomi, Redmi, POCO: try *#*#6484#*#* (the CIT menu). Some HyperOS versions block it.
3. 3Tecno, Infinix and other MediaTek phones: *#*#3646633#*#* opens Engineer Mode on some. Open Hardware Testing only and change nothing.
4. 4Vivo, Oppo, Realme, OnePlus, Google Pixel: we found no code we can stand behind, so we list none. Use the manual tests below.

Warning. Never assume a code works on every model. A code that does nothing is normal, not a fault. Never dial a code that starts with ## or ** or that mentions reset.

Manual tests that work on any Android

1. 1Touch: Settings > System > Developer options > Pointer location. Drag across the whole screen. The trace must be continuous with no gaps. Turn it off afterwards. (Enable Developer options by tapping Build number 7 times in About phone.)
2. 2Display: see Display Testing for colour and dead pixel tests.
3. 3Auto-rotate and motion: rotate the phone. The screen must turn smoothly.
4. 4Proximity sensor: call a number and cover the top of the screen. The display must turn off.
5. 5Fingerprint and face unlock: add yours and unlock five times.
6. 6Compass: open Maps or a compass app and turn around. The direction must follow.
7. 7Vibration: turn on keyboard vibration or ring in vibrate mode.
8. 8SIM and memory card tray: open and close it, and test every slot with a SIM.

Genuine software and account lock

1. 1Open Google Play Store > profile picture > Settings > About > Play Protect certification. It should say the device is certified.
2. 2Settings > About phone: the model, Android version and storage must match what the seller says and the box.
3. 3Check Settings > Passwords & accounts or Users & accounts. There must be no account that is not yours.
4. 4Ask the seller to factory reset it in front of you. After the reset, the phone must reach setup without asking for a Google account you do not know. A phone that asks has Factory Reset Protection active and is locked to the old owner.

Warning. A phone that asks for the old owner's Google account after a reset is locked to them. Do not buy it.

Check the model is real

Compare the model, memory, chipset and cameras with the specifications of the same model. If a phone claims a flagship chip but is slow, or the Settings screens look different from other phones of the same model, be careful. Fake and clone phones copy the look of famous models.

Common questions