How to check the condition of the Xiaomi phone: 7 ways to fully diagnose

Buying a used Xiaomi or want to assess the current state of your smartphone? Even new devices can have hidden defects, and used ones can have even more. In this article, you will find expert methods of verification used by service centers and experienced users. We will analyze diagnostics from basic tests (screen, buttons) to deep analysis of hardware and software.

Xiaomi phones have built-in diagnostic tools that many users don’t know how to activate, such as a hidden engineering menu that allows you to check the performance of sensors, and the USSD codes to get data on battery life, you will learn how to interpret test results and what to look for when buying or before selling a device.

Important: Some problems (such as a bloated battery or overheating of the processor) may not be obvious on a surface inspection, and our instructions will help you to identify them in 10-15 minutes without special equipment.

1. External inspection: what the "face" of the phone gives

Start by visually checking the body and screen, and even small scratches on an aluminum frame can indicate falls, and micro-cracks on the glass can indicate internal damage to the display.

• 🔍 The gaps between the body and the screen are a sign of a replacement display or deformation after impact.
• 📱 Crushing on cameras — even if the glass is whole, the internal lenses could shift.
• 🔋 Bloating of the back cover is a signal of a bloated battery (especially relevant for models older than 2 years).
• 🎨 Uneven body coloring - possible after unqualified repairs.

Swipe your finger around the edges of the screen: if you feel irregularities or “waves”, this can mean that the display has unstuck from the touchscreen. Also check the operation of the touch buttons (if you have them in your model): press them with effort - there should be no backlash or creak.

⚠️ Warning: If the phone has been in water, even after drying, there may be traces of corrosion. Illuminate the flashlight into the USB-C and 3.5 mm connectors (if any) — green or white divorces indicate oxidation of the contacts.

2. Screen check: tests for broken pixels and touchscreen

The display is the most vulnerable element of the smartphone, and to diagnose it, use built-in tests or third-party applications like Screen Test.

1. Go to Settings → About the phone → All specs.
2. Tap 5 times on the item MIUI version - the CTA menu will open (in some models you need to press the Core).
3. Select Test Display and consistently check all colors (red, green, blue, black, white).

Pay attention to:

• 🖥️ Broken pixels are bright dots on a monochromatic background.
• 🌈 Stripes or divorces are a sign of matrix damage.
• ☀️ Uneven lighting (especially at the edges).
• 👆 Touchscreen Sticking – swipe your finger across the screen in the Touch Screen Test app.

To check for automatic brightness, go to Settings → Display → Autobrightness and cover the light sensor (usually next to the front camera) with your finger. The screen should go out in 1-2 seconds.

3. Diagnosis of the battery: how to find out the real wear

The battery is the first component that degrades over time, and to check its status on Xiaomi, use secret codes or the AccuBattery app. The most accurate method is through the engineering menu:

##4636##

In the menu that opens, select Battery Information.

• 🔋 Charge level (must match the indicator in the status bar).
• 📊 Good is normal, Unknown or Replace soon is a problem.
• 🔌 Temperature (normal: 25–40°C when charging, above 45°C is overheating).
• ⚡ Voltage (3.7–4.4V for most models).

For more detailed analysis, install AccuBattery and check:

• 📉 Capacity (if less than 80% of the factory capacity, the battery is worn out).
• 🔄 Charging cycles (more than 500 cycles are a reason to replace).
• ⏱️ Charging time (longer than 2 hours with fast charging – battery or power supply problem).

⚠️ Warning: If the phone turns off at 20 to 30 percent charge, it's a sign of severe battery wear or a power controller malfunction, in which case a battery replacement may not solve the problem, but a board diagnosis will be required.

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To extend the life of the battery, avoid charging to 100% and discharging below 20%.

4.Iron testing: processor, memory, sensors

To check the phone's "stuffing," use the built-in engineering menu or apps like CPU-Z and AIDA64.

1. Open Settings → About the phone → All specs.
2. Tap 7 times on the kernel version (on some models - on the MIUI version).
3. Choose Test Hardware and run tests one by one.

Pay attention to:

• 🖥️ Processor: Check heating after 5 minutes of play or test in AnTuTu. Normal to 60°C, above 70°C - overheating.
• 💾 Memory: In AIDA64, see Memory Usage. If free RAM is less than 20% in closed applications, it may leak.
• 📡 Sensors: In the engineering menu, select Sensor Test. Check the gyroscope, accelerometer, compass and proximity sensor.
• 🔊 Speakers and microphone: Call another phone and check the sound at maximum volume (no wheezing).

For a deep flash memory check, use the command in ADB:

adb shell dumpsys diskstats

If there are lines with bad blocks in the output, this is a sign of memory wear and tear, which can lead to data loss.

5. Software verification: viruses, root, firmware

Xiaomi smartphones are often victims of viruses or incorrect firmware, especially if you bought with hands. Start by checking the version of the MIUI:

1. Go to Settings → About Phone → MIUI version.
2. Compare it to the official update page.
3. If the version is very outdated (for example, MIUI 12 with the current MIUI 14), this may indicate custom firmware.

To check for viruses:

• 🛡️ Install Malwarebytes or Dr.Web Light.
• 🔍 Check the list of installed apps in Settings → Apps. Delete suspicious ones (e.g., with names in Chinese).
• 🔑 Check for root rights with Root Checker. Official firmware should not have root on it!

If the phone spontaneously restarts or brakes, check the system logs:

adb logcat | grep -i "error\|warning"

Errors such as E/AndroidRuntime or W/BatteryService will indicate problem processes.

⚠️ Warning: If Settings → Additional → Developers are enabled with the USB debugging option without your knowledge, this is a sign that the phone may have been hacked or used to test the software.

6.Telecommunication test: network, Wi-Fi, Bluetooth and GPS

Communication problems may not be immediate, but they can be a huge spoiler to the experience.

• 📶 Cellular network: type ##4636##, select Phone Information and see Network Type. If LTE or 5G is displayed HSPA, modem problems are possible.
• 📶 Signal strength: In the same menu, check Signal Level (in dBm). Normal: from -70 to -100 Less -100 is weak signal.
• 📡 Wi-Fi: Connect to a 5 GHz network. If speeds are below 100 Mbps, check the antenna (contact may have been cut off).
• 📍 GPS: In Google Maps, enable high-precision location detection. If the coordinates jump more than 20 meters, the module may malfunction.
• 🔵 Bluetooth: plug in your headphones and check the stability of the connection at 10 meters away. Breaks are a sign of a chip malfunction.

To verify the IMEI (Unique Phone Identifier) type:

*#06#

If Null or an incorrect IMEI is displayed, the phone may have been recovered after the theft or has problems with the modem.

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If the phone does not catch the network in places with good coverage, and the SIM- card works in another device – the problem is in the antenna unit or modem.

7 Hidden problems: what is checked in service centers

Even if the phone looks good, there may be some hidden defects that will show up later, and this is what the professionals check for.

• 🔧 Charging connector status: plug the cable and swing it to the sides. If charging is interrupted, the connector is shattered.
• 📱 Integrity of plumes: When pressed on the screen, no artifacts should appear in the area of cameras or buttons.
• 🔋 Power Controller: If the phone doesn't turn on without a charger connected, the power circuit may malfunction.
• 💻 The condition of soldered contacts: Overheating at one point in the body may indicate chip detachment (e.g., Snapdragon or Mediatek).

To check for tips on the screen (interference from other components), do:

1. Set up the black wallpaper.
2. Run the video on YouTube at full volume.
3. If waves or ripples appear on the screen, this is a sign of poor assembly or damage to the plume.

Critical point: Xiaomi models with AMOLED- screens (e.g. Xiaomi 13, Redmi K60) can experience pixel burnout over time. Check this with a test against a monotonous background (especially gray) - if you see the contours of the interface, the screen is worn out.

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Before buying a used Xiaomi, ask the seller to remove the protection of the Mi Account (if any).

FAQ: Frequent questions about Xiaomi's diagnostics