How to check the condition of the Xiaomi phone: full diagnosis

Xiaomi smartphones, including the Redmi and POCO sub-brands, are famous for their excellent price-performance ratio. However, like any complex electronics, they require periodic technical inspection to identify hidden defects or wear of components. Owners often wonder how to make sure that the device works properly, especially if it is purchased on the secondary market or has a solid life. Checking the condition of the Xiaomi phone is not just a look at the screen, but a set of procedures to assess the health of the battery, the integrity of the matrix and the operation of touch sensors.

MIUI or the new HyperOS have powerful self-diagnostic tools that often remain hidden from the eyes of the average user. Using built-in utilities and engineering codes allows you to access data that is not displayed in the standard settings menu. Regular diagnosis helps prevent sudden breakdowns and extend the life cycle of the gadget, keeping its performance at a high level.

In this article, we will take a look at all the ways you can test your device, find hidden menus, interpret test results correctly, and distinguish software failures from physical wear and tear. Understanding the real state of your smartphone is key to safe use and proper maintenance.

Diagnostics through CIT Engineering Menu

The most complete and professional tool for checking is the hidden CIT (Calibration Item Test) section, which is designed for engineers in the factory, but is available to every user. To enter this mode, you need to open the standard phone dialer and enter a special combination of characters: ##64663##. Once you enter the last character, the menu will open automatically, without having to press the call button.

Inside the interface CIT And you can see a long list of tests for each hardware component, and you can check the vibrator, the microphone, the speaker, GPS-Each test is run separately and requires the user to perform certain actions, such as tapping a screen or saying a phrase into a microphone. Test results are usually marked with green (Pass) or red (Fail).

⚠️ Warning: Be careful when testing sensor reset functions. Incorrect calibration of an accelerometer or gyroscope can lead to incorrect screen positioning and autorotation problems.

Special attention should be paid to tests related to Touchpanel (touchscreen) and display, the engineering menu allows you to identify “dead zones” where the sensor does not respond to touch, and also check the uniformity of the backlight, which is critical when buying a used device, since visual defects of the touch screen can be invisible on a cursory examination.

• 📱 Touchpanel: Check the sensor’s response to the multi-touch and draw lines throughout the screen area.
• 🔋 Battery: Displaying the exact voltage, temperature and charge status in real time.
• 📡 Receiver/Speaker: Test of sound speaker and conversational speaker for wheezing or distortion.
• 📷 Camera: Quickly check focus and performance of both cameras without running the main app.

Checking the status of the battery and battery

Battery status is one of the most important parameters for any smartphone. Over time, the capacity of lithium-ion cells decreases, leading to rapid discharge and unexpected shutdowns. Unlike the iPhone, Android does not have a single standard for displaying the “health percentage” of the battery in the settings, but Xiaomi owners can use system reports.

To get detailed statistics, go to Settings → About Phone → All settings and quickly click on Kernel Version several times. This action will open the hidden Battery Stats menu. This displays the number of recharge cycles, current full capacity and residual capacity. If the difference between full and residual capacity is large, this is a signal of degradation of the power cell.

It's also useful to use third-party but proven apps from Google Play, such as AccuBattery or Ampere.They accumulate data in the background over a few days of use to build an accurate wear schedule. System data may not always be accurate immediately after a reset, so monitoring in dynamics gives a more objective picture.

⚠️ Warning: If you notice that the case of the smartphone in the area of the camera or the bottom of the screen is swollen, immediately stop charging.The bloated battery is fire hazard and requires immediate replacement at the service center.

Testing the display and sensor for defects

The screen is the most fragile and expensive component of a smartphone. Checking the matrix for broken pixels and “burnout” (especially for AMOLED screens in Xiaomi 13/14 or Redmi Note Pro models) should be done regularly. The easiest way to do this is by running a video with monochrome white, black, red, green and blue at maximum brightness.

In the CIT engineering menu, there's a special Display test that automatically switches colors. Take a close look at the surface: any points that differ in color from the main background are defective pixels. It's also worth checking for "ghosts" - residual images of icons that don't disappear after a change of picture, which is a sign of degradation of organic LEDs.

Multi-touch testing is particularly important. Qualcomm and MediaTek processors today support 10 simultaneous touches. Touchpanel tests, draw 10 lines with your fingers. If lines are interrupted or not drawn at all, the plume is in contact with the area or the touch layer is damaged, often after falls or poor repairs in the past.

• 👁️ Burnout: Look for gray silhouettes of a keyboard or status bar on a white background.
• 🌈 Color Transmission: Check gradients for green ribbon or stripes.
• ✋ Response: Evaluate if there are any delays in fast text printing or playing.

Analysis of memory and system performance

Slowdowns in interfaces and applications are often not due to the age of the processor, but to filling in or errors in the operation of flash memory. Xiaomi smartphones use memory types eMMC (in public sector) and UFS (in flagships), You can check the speed of reading and writing using benchmarks, for example, AIDA64 or AndroBench.

To quickly assess the state of memory, go to Settings → About Phone → Storage. The system will show what the memory is occupied. A critical parameter is the availability of free space: if less than 10-15% of the total volume is free, the internal drive speed drops significantly due to the algorithms for leveling out wear, and it is also worth checking for a log file or a crowded cache of junk files.

RAM verification (RAM) is done through a developer menu or third-party utilities. If only 200-300 MB are left free after cleaning the memory, and few applications are running, there may be a memory leak by the application. In this case, rebooting or removing problematic software helps. Memory optimization in MIUI does this automatically, but manual control will not interfere.

Checking cameras and multimedia modules

The camera is one of the main selling points of Xiaomi smartphones. To check its condition, it is not enough to take a photo. You need to test autofocus. You need to point the camera at close range, and then at a remote object. Focus should "cling" quickly and clearly. If the lens "walks" back and forth and can not fix, perhaps damaged OIS module (optical stabilization) or contaminated laser focus sensor.

The sound subsystem also requires checking. Turn on the voice recorder and record the voice in a quiet room, then play the recording. Hissing, crackling, or a quiet sound may indicate a malfunction of the microphone. To check the stereo speakers, turn on the music at maximum volume: the sound must be uniform on both sides (bottom and top / front).

Remember to check the flash and the proximity sensor. Turn on the flashlight, it should burn smoothly, without blinking. The proximity sensor (located next to the front camera) is checked during the call: if you put your hand to the top of the screen, it should go out. A faulty sensor will cause you to constantly burn the screen and press your cheek during the conversation.

• 📸 Stabilization: When shooting video in 4K The camera should not shake or make a mechanical knock.
• 🎤 Noise suppression: A second microphone (usually on top) must cut off background noise when recording video.
• 🔦 Flash: Check the operation in mode SOS or as a flashlight during 1-2 heat-up.

Additional codes and hidden functions

In addition to the main engineering menu, in the shell MIUI And Android has other useful diagnostic codes, like code ##4636##, which opens the testing menu, where you can see details about Wi-Fi connection, battery status and usage statistics. IMEI-codes that must match those on the box and in the settings.

There is also a code ##7780## that initiates a Factory Reset. Be very careful: using this code will delete all data from your phone. It is better not to enter it just for fun unless you plan to completely clean the device.

To check the quality of the network and switch modes (2G/3G/4G/5G), you use the menu called by the code ##4636## (Phone Information) and you can see the signal level in dBM (the closer to 0, the better the norm is -80...-100 dBM) and the type of connection. This is useful if you lose the Internet in certain areas.

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Save important codes in your notes or add contacts with the names "CIT Test" and "Info about the phone" with the corresponding numbers, which will allow you to run a diagnosis in one click without looking for combinations on the Internet.

Frequently Asked Questions (FAQ)

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Regularly checking your smartphone through the CIT engineering menu takes only 5-10 minutes, but it can reveal 90% of hidden problems before they lead to a breakdown or loss of data.