How to check the performance of Xiaomi: a complete diagnosis

Xiaomi’s modern smartphones are complex computing devices that integrate software closely with the hardware. When a device starts to run unstable, artifacts appear on the display or the battery suddenly discharges, the user needs to understand whether there is a physical damage or a software failure.

The Android ecosystem, which runs MIUI or HyperOS, has powerful self-diagnostic tools that manufacturers often hide from the average user to avoid accidental changes to critical settings, but with specific commands or menu paths, you can run a deep check of all components, from the microphone to the communication modules.

Checking the health of Xiaomi smartphone is especially relevant when buying a used device or after a fall.This allows you to assess the real state of the battery and eliminate the presence of hidden defects in the matrix. In this article, we will discuss all available testing methods, from built-in functions to third-party utilities.

Using the CIT Engineering Menu for Diagnostics

The most effective way to check is to log into a special engineering menu known as the CIT (Customer Information Test), which is an interface designed by the company's engineers to test the device in the factory before sale, and accessed through the standard Phone application by entering a special digital combination.

To get to the menu, open the dial and enter the code ##6484##. The system automatically recognizes the sequence and redirects you to the test list. If the code didn't work, try the alternative combination ##4636##, which opens the test menu of information, although it is less functional for checking hardware. In the CIT engineering menu, you will see a list of all available modules of your particular device.

Each item on the list corresponds to a specific node of the device, for example, the TouchPanel item is responsible for checking the touchscreen, and the Receiver is responsible for checking the conversational speaker. You can run tests sequentially, marking them as "Pass" (successful) or "Fail" (error), which is the perfect way to test Xiaomi's health before buying from hand, since it allows you to detect even small defects.

It's important to understand that some tests may require specific actions, for example, a vibration test will just turn on the motor, and an accelerometer test will ask you to tilt the device in different directions, and if a module fails to pass the test, this is a direct signal that you need to repair or replace the component.

Detailed check of the display and sensor

The screen is the most vulnerable element of any smartphone. Even if the glass, matrix or digitizer (touch layer) may have hidden defects. In the CIT engineering menu, select Display or Color. The screen will start to shimmer in different colors: red, green, blue, white and black. Your task is to carefully examine the surface for broken pixels that glow the wrong color, or spots ("broken" zones) that do not change shade.

Special attention should be paid to the sensor test. In the menu, select TouchPanel. The screen will show a grid or sequence of points that you need to draw with your finger. The touchscreen should respond instantly and accurately throughout the area. If there are areas in the corners or in the center where the line is interrupted or "shaking", this indicates sensor degradation or poor contact of the plume.

Often, users experience phantom taps when the phone opens the apps itself, and this can also be detected in diagnostic mode by leaving the device on the table for a couple of minutes in sensor check mode, and if the line starts moving without touching, the digitizer is faulty.

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The broken pixels and the touchscreen dead zones are a physical defect that cannot be software-corrected, and the only solution is to replace the display module.

For deeper analysis, you can use third-party applications that output technical information about the temperature and voltage of the matrix, but the visual test in CIT remains the most reliable method.

Battery Testing and Charging

Battery status is a critical parameter for any mobile device. The Battery or Charger section is often available on Xiaomi's engineering menu. It shows the current voltage, battery temperature, and charging status. Pay attention to the voltage: if it jumps heavily under load or falls rapidly after being decharged, the chemical element's life is exhausted.

Checking the power controller is also important. Connect the original cable and see if the system recognizes the type of charger. The menu should display "Fast Charge" or "Quick Charge" if you use the appropriate unit. If the phone charges slowly even from a powerful power supply, the problem may be a USB-C connector or controller.

To assess the actual wear of the battery, you can use a command ##6485##. In the window open, find the parameters. MB_06 (battery-state: Good/Bad) and RF_02 (Compare the design capacity to the factory capacity if the residual capacity is less than 80% From the beginning, you should think about replacing the battery.

Don't ignore the heat of the device while charging. In the Temperature section, you can track readings from various sensors; heating above 45 degrees in plain is critical. If the smartphone warms to such values without running heavy applications, it is a sign of a processor malfunction or a short circuit in the power supply chain.

Verification of communication, sound and camera modules

Communications are checked in the Receiver, Speaker, and Headset sections. Turn on the test and see if there is any wheezing, cod, or distortion. The microphone is checked at Mic: you need to say something, and then play the record. The sound quality should be clean, no noises or echoes.

The cameras are tested separately for each module. The Front Camera and Back Camera menus include a viewfinder. Check if autofocus is working, if there are black spots in the photo (dust on the matrix) and if the flash is functioning. Often, the main module works, and the wide-angle or macro camera does not, so you need to test all the lenses.

Wi-Fi, Bluetooth and GPS communication modules also have their own tests. For GPS, run a test and wait for the coordinates to be determined. If satellites are not caught for 1-2 minutes outdoors, it is possible that the antenna module is damaged or unplugged. For Wi-Fi and Bluetooth, run a network search; if the list is empty, although there are devices around, the module is defective.

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Before the sound test, be sure to turn off all connected Bluetooth devices so that the sound goes through the phone’s speaker, not through headphones or a speaker.

Diagnostics with third-party applications

If Xiaomi’s built-in tools don’t seem informative or unavailable, Google Play apps will come to your rescue. One of the most popular and reliable tools is CPU-Z or AIDA64. These tools provide comprehensive information about hardware: processor model, RAM, real screen resolution and battery status.

Another powerful tool is the Phone Info SAM app (which also works on Xiaomi) or specialized testers like TestM. They run all the tests automatically and give the final report, which is convenient when you need to quickly check the device and there is no time to manually go through the items of the engineering menu.

But it's worth remembering that third-party programs have limited access to hardware compared to factory tests, and they can't run, for example, specific frequency test vibrations or test individual proximity sensors in the way that CIT does, so use them as an addition to, rather than a replacement for, built-in diagnostics.

Analysis of system logs and error reports

For advanced users who want to understand the reason for constant reboots or freezes, there is a Bug Report function. It is located in the Settings menu → About Phone → Version of the kernel (you need to quickly tap the kernel version several times) or through ADB. This method allows you to save a log file in which all system processes are recorded before crashing.

Log analysis requires Android development knowledge, but the fact that a file is present can help the service center diagnose the problem faster. If the phone goes into a cyclic bootloop, it often helps to log into Recovery mode by pressing the power and volume button up.

In Recovery mode, you can try to reset your settings (Wipe Data), but it will delete all the data. If the problem persists after the reset, it is a hardware malfunction, and the software methods will not help. In logs, this is often reflected as a read error from flash memory (eMMC/UFS).

Frequent problems and their solution

One common problem is that the proximity sensor falsely fires when the screen goes out during a conversation, and you can check this at Proximity on the engineering menu. If the values do not change when you close the top of the screen with your hand, it may be that the sensor is contaminated or misaligned after the glass falls/replaces.

Users also often complain about fast discharge, and in addition to battery wear, the cause may be a "rumbled" process in the system. → You can see the battery's consumption statistics, and if an unknown application consumes a lot of power in the background, it should be removed or restricted.

⚠️ Warning: Do not try to disassemble your smartphone to check the plumes if the device is warranty. Breaking the seals will result in a denial of free repair. CIT safe and do not require opening of the body.

If the diagnostics show that one of the key modules (motherboard, screen) has malfunctioned and the warranty period has expired, weigh the cost of repair. Sometimes replacing a display or battery can cost up to 70% of the price of a new device, making buying a new gadget a more rational decision.

⚠️ Warning: If during the test the battery started to heat up sharply or swell, immediately stop using the device and disconnect it from charging.