Owners of Xiaomi, Redmi and Poco smartphones often face the need to diagnose the device in depth, especially after buying or falling. Standard system settings do not give a complete picture of the state of the hardware, so the developers built a hidden engineering tool – Hardware Test. This mode allows you to check the work of each individual component, from the screen and touch screen to cameras and microphones.
Many users are looking for information on how to run these tests because it is the only way to objectively assess the build quality of a gadget. Unlike third-party apps from the Play Market, the built-in test has direct access to drivers and does not require root rights. Understanding how this tool works will help you avoid buying a defective device or identify hidden defects before contacting the service.
In this article, we will discuss in detail what is CIT (Calibration In Test), what codes work on current versions of MIUI and HyperOS, and how to interpret the results of the validation, you will learn which parameters to pay attention to first and why standard validation can miss important malfunctions.
What is Hardware Test and Why You Need It
Hardware Test mode, often called CIT, is a diagnostic utility pre-installed at the firmware level, and its primary purpose is to allow engineers in the factory and technicians in service centers to quickly test the functionality of all hardware modules. For the average user, it is a powerful tool that allows you to conduct independent examination of a smartphone without connecting to a computer.
The main advantage of this method over third-party programs like CPU-Z or AIDA64 is that it can not only read information, but also force the components to activate: you can make the vibrator hum, the screen burn a certain color, and the camera take pictures by timer, which is critical for detecting defects that manifest only under load.
⚠️ Note: Do not change the values in the Calibration subsections unless you are an expert. Resetting factory calibration data can cause sensors to malfunction, GPS Or sound, and it's going to be very difficult to recover software.
This tool is especially useful when buying a used device or a restored one. Often unscrupulous sellers change the display to a cheap analog or re-sweetened module, which the system determines as original, but which does not pass the test for the uniformity of the glow or the accuracy of the touchscreen.
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Hardware Test is the only way to test the hardware of the smartphone at the driver level without installing additional software and obtaining root rights.
How to enter the engineering menu Xiaomi
There are several ways to run diagnostics, but not all of them work on newer versions of the shell. USSD-You don't have to look for hidden shortcuts or download files.
Open the standard "caller" and dial the combination ##6484##. If the code is entered correctly, the Phone app will close, and in a second the CIT menu will open with a list of all available tests. Some models, especially old or specific regional versions, may work the code #4636##, but it more often leads to the network debugging menu, rather than the full hardware test.
- 📱 Main method: Type ##6484## in the app for calls.
- 🔍 Alternative: Go to Settings → The phone. → Version. MIUI Quickly press 10 times on the version logo (not all models).
- 🛠️ For the Advanced: Use ADB-Adbash shell am start am am am -n com.miui.cit/com.miui.cit.CITActivity computer.
If none of the codes work, your firmware may have operator or region limitations, and you can try downloading the official Service & Feedback app (formerly known as Services & feedback) from the GetApps store. Inside this app, there is often a “Device Check” button that runs the same testing interface.
Detailed check of the display and touch screen
One of the most important checks on the list is display testing. On the Hardware Test menu, you'll find items related to Display, Color and Touch.The screen is the most fragile and expensive component, and its defects may be invisible in normal use, but critical for comfort.
When choosing a color test, the screen is filled with a monochrome image. You need to carefully examine the matrix for broken pixels, uneven illumination (lights) or yellow spots. This is especially true for LCD screens of budget Redmi models, where factory defects are more common. Switch colors (black, white, red, green, blue) and look at the screen from different angles.
Special attention should be paid to the multi-touch test, which is a touch sensitive mode, and when you run your finger, you leave a trace. You swipe with several fingers at the same time, draw complex shapes. If the line is interrupted or the finger is shaking for no reason, it is a sign of a digitizer malfunction or poor screen quality.
Why can't the touchscreen test work?
Also in this section, you often check the accelerometer and the gyroscope, which are tied to the orientation of the screen, put the phone on a flat surface and press the calibration button, and if the level doesn't align, the sensors are down, which can interfere with navigation and games.
Diagnostics of cameras, sound and microphones
Modern smartphones have a lot of cameras and microphones, and it can be difficult to manually check them all. In Hardware Test mode, there are separate items for each camera: main, wide-angle, macro and front. The system itself switches lenses, allowing you to assess the focus and the presence of dust under the lenses.
So, when you test the sound, you hear a sequence of melodies through the main speaker, the speaker, and the vibrator, which helps you detect wheezing, crackling, or total failure of the audio track. And for microphones, there's a recording test: you have to say something, and then the system will play back the recording, and that's the best way to know if the people are listening to you.
- 🎥 Cameras: Checking focus, zoom and switching between modules.
- 🔊 Audio: Test of main and spoken speakers at different frequencies.
- 🎤 Microphones: Recording sound from the main and noise-canceling microphones.
Note the flash test. It should light up smoothly, without flickering. If the flash blinks or has a dull hue, it may indicate problems with the power controller or oxidation of contacts, which often happens after moisture is injected.
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When testing cameras, be sure to wipe the lenses before starting, and dust and fingerprints can be mistaken for matrix defects or defocusing.
Verification of communications, sensors and other modules
Besides multimedia, it's critical to check the communication modules, you can check Wi-Fi, Bluetooth, GPS and cellular networks on the CIT menu, you can run a scan of the environment for Wi-Fi and Bluetooth, and if the smartphone can't see the networks or devices that other gadgets can see perfectly, the problem is the antenna module.
Test GPS It's going to show you the number of satellites you can see and the coordinates are accurate, and if you want to get the navigator to work properly, you've got to catch the phone. 4-5 If you're in sight of satellites. 0 satellites even in the open air, perhaps the antenna plume has departed or the antenna itself is defective. GPS-module.
A separate section is dedicated to proximity and light sensors. Put your hand to the top of the screen, so the proximity sensor should lock the screen (change from 5.0 to 0.0), which is critical to ensure that the phone does not turn on a video call with your cheek during a conversation.
| Component | What we check. | Normal result |
|---|---|---|
| Wi-Fi | Network scanning | List of available networks |
| Bluetooth | Searching for devices | Visibility of other gadgets |
| GPS | Satellites | Coordinates and >4 satellites |
| Sensor | Approximation | Reaction to the hand-off |
Don't forget to check the USB-C charging connector. The Charger test shows the cable connection status and current. If the cable's status is lost when you move, the connector is loose or oxidized.
Interpretation of results and frequent errors
After passing all the tests, the system can produce a final report, but users are often frightened by red labels or Fail statuses without understanding their context, and it is important to distinguish between software failures of the test and real-life defects.
For example, a Wi-Fi test may give an error if you are in a zone without networks (Faraday cage) or if the Wi-Fi module is busy with another system process. SIM-The card will give an error if the card is not inserted or blocked. PIN-So before you start a full diagnosis, make sure the phone is properly prepared.
☑️ Preparation for the test
If a particular test is constantly failing, try restarting the device and starting it again. A single failure is not a cause for panic, but if, for example, the vibration test is silent and the system is on vibration, it is 100% a sign of motor failure.
⚠️ Warning: If the touchscreen or proximity sensor stops working after the Calibration Reset, don't try to "cure" it with flashing. NV-data or contact the service for factory calibration.
For complete certainty, you can create a log file (if this option is available in your version of CIT) and save it. This file may be required at the service center to prove the warranty case.