Many owners of smartphones Xiaomi, Redmi and POCO sooner or later they encounter a mysterious item on the menu called the “factory set test” or CIT (This hidden section is designed by engineers to diagnose the hardware of the device before sale, but it is also open to ordinary users, allowing them to independently check the health of all components of the gadget without going to the service center.
Understanding what the app is is critical when buying a new or used device, and when troubleshooting after a drop or moisture hits. Unlike normal settings, this mode gives direct access to hardware management, bypassing the standard software constraints of the Android operating system, and this is where you can see real-world sensor readings that are not displayed in the normal interface.
In this article, we will take a closer look at the functionality of the engineering menu, Step-by-step describe the login process in various ways, and analyze what tests you need to pass to fully check Xiaomi smartphone. You will learn how to distinguish a software failure from a physical screen failure or speaker using only the manufacturer’s built-in tools.
What is CIT Mode and Why is it Needed?
CIT (Customer Inspection Test) is a specialized diagnostic tool built into MIUI or HyperOS firmware, and its primary purpose is to automate the factory assembly quality check process. Each button on this menu runs a separate test of a particular module, from vibration check to gyroscope calibration, and it's not just an "app" as we know it is, but a system tool with extended access rights.
Using this mode, it reveals hidden defects that may not be apparent in normal use, such as broken pixels on the screen or micro-gaps in the dynamics often only detect when the forced load is created by the test mode. For service center specialists, this is the main tool for primary diagnostics.
⚠️ Warning: Do not change settings in sections you do not know the purpose of (such as touchscreen calibration or base stations) if you are not sure what you are doing. Incorrect calibration can lead to sensor malfunction or signal loss.
It's important to understand the difference between the normal settings menu and the engineering menu. In the standard "About the phone" section, you see only general information, whereas CIT Mode shows raw data from sensors, which allows you to see, for example, the actual temperature of the battery under load or the exact number of recharge cycles, if this function is supported by a particular model.
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CIT mode is a bridge between the user and the hardware of the smartphone, allowing you to conduct deep diagnostics without installing third-party software.
How to enter the engineering menu Xiaomi
There are several proven ways to start a diagnosis, and the simplest and most versatile method is to use a special method. USSD-This method works on the vast majority of models, from the old Redmi Note to the latest flagships of the Xiaomi 14 series.
To enter, open the call app and dial the following character combination: ##6484##. If the code is entered correctly, the Factory Dial Test menu will open automatically, without having to press the call button. In some regions or global firmware versions, the code may differ by ##4636##, but it more often leads to the phone information menu rather than the full CIT.
- 📱 Code through the call: dial ##6484## in the phone app.
- ⚙️ Through Settings: Go to Settings → The phone. → All parameters. → The kernel version (click 5 times fast).
- 🔍 Search: in some versions MIUI You can find the item "Testing" through a search in the settings.
If none of the codes work, your firmware version may have carrier restrictions or regional locks, so you can try logging in through the Kernel Version menu. → About the phone, find the line "kernel version" and quickly click on it 5-7 This action often duplicates the function. USSD-The same code and opens the same test menu.
What if the code doesn't work?
The main sections of diagnostics and their functions
The test menu interface is a list of all the hardware components of your device, each item corresponds to a separate module, navigation is done by simply touching, and it is important to know that some tests are automatic, and others require your direct participation.
The most popular screen test is the one that checks the screen for broken pixels, ghost touch and evenness of the backlight, and when it starts, the screen is colored in different colors (red, green, blue, white, black), which helps to detect matrix defects that are invisible in normal mode.
| Name of the test | Function | What we check. |
|---|---|---|
| Display / Screen | Matrix verification | Broken pixels, color reproduction, touchscreen |
| Receiver / Speaker | Audio test | The work of conversational and basic dynamics |
| Vibrator | Vibromotor | The presence of vibration and its strength |
| Touchpanel | Sensory layer | Sensor accuracy and responsiveness |
| Proximity sensor | Approximation sensor | Reaction to face-to-face (important for calls) |
The Proximity sensor section is particularly noteworthy, and it's the one that's responsible for quenching the screen during a conversation, and if you have a problem with that (the screen doesn't go out or doesn't light up when you remove the phone from your ear), this test will show whether the sensor itself is working or if there's a software problem.
Detailed screen and sensor check (Touchpanel)
Touch screen testing is one of the most important procedures, especially if you buy a used device. On the CIT menu, this test is usually called "Touchpanel" or "Touch." Once it starts, the screen turns black, and the system asks you to swipe your finger along special lines or completely paint over the screen to confirm the responsiveness of the sensor.
In the test, you can detect dead zones where the sensor doesn't respond to touch, or, conversely, areas of spontaneous pressing. This is critical for Xiaomi smartphones, because the quality of the sensors in different assembly plants may differ, if the line is interrupted or not drawn in a certain place, this is a clear sign of a defect.
⚠️ Warning: Before starting the screen test, be sure to wipe the display and remove the protective glass or film if they interfere with accurate diagnosis.
Also available in this section is the Multi-touch test, which shows how many simultaneous touches your screen supports. Modern models are normal for 10 simultaneous touches. If the counter stops at a smaller number, there may be problems with the plume or the display controller.
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When you test the touchscreen, pay attention to the corners of the screen, and that's where you're most likely to have responsiveness problems after a device drops.
Diagnostics of sound, vibration and sensors
Audio tests in CIT Mode are divided into several categories: checking the main speaker (Speaker), the conversation speaker (Receiver) and microphones. When you run the test, the speaker will start playing a melody or white noise. You need to evaluate the purity of the sound, the absence of wheezing, rattling or distortion at maximum volume.
Special attention should be paid to the test of microphones. Modern Xiaomi smartphones are equipped with several microphones (main, noise cancellation, voice recorder), in the diagnostic menu, you can alternately activate each of them and record your voice to make sure that all channels are working correctly, which will help to identify the problem when you are not heard by the interlocutors, although the speaker works.
- 🔊 Speaker Test: Checks the volume and cleanliness of the main speaker.
- 📞 Receiver Test: Tests the top speaker for conversations.
- 🎤 Mic Test: Recording sound from different microphones to check video and call recording.
- 📳 Vibrator: short vibration to check the motor.
Don't forget the light sensor and the gyroscope. The Gyroscope is especially important for mobile gaming enthusiasts. In this mode, you can calibrate the sensor by putting the phone on a flat surface and pressing the appropriate button, which often solves problems with the "floating" sight in shooters or the wrong turn of the screen.