Xiaomi and Redmi smartphone owners often experience a cryptic CIT on-screen sign, often after resetting or when a new device is turned on. Many users panic, believing that the phone is broken or infected with a virus, but it is actually a regular tool of engineers. CIT stands for Cell Identity Test, although in the context of mobile devices it is more often interpreted as China Information Technology or just an engineering component testing menu.
This is a hidden part of the operating system, designed to quickly check the health of all the modules of the smartphone, from the display and touch screen to the accelerometer and radio module. The average user does not need to get there, but knowing its existence can save the situation if the phone has stopped responding to commands or requires accurate diagnosis before handing over for repair.
In this article, we will take a closer look at how this mode works, what tests it includes, and most importantly, how to safely exit it if you happen to get there. CIT-The menu will help you distinguish a software failure from a real hardware malfunction.
The main purpose of the CIT regime
The main purpose of the CIT (Cell Identity Test) mode is to give service engineers a tool to quickly check each node of a smartphone without having to install third-party software. When a device comes off the assembly line, this is the interface that checks the build quality, and if you see this screen, it means that the system is trying to start the diagnostic protocol or an engineering menu login command was performed.
Unlike the regular MIUI user interface, there are no extra animations or beautiful icons, and you have a rigorous list of tests, each of which is responsible for a specific component. It's important to understand that being in CIT mode doesn't mean a breakdown, it's just a diagnostic tool built into the firmware. The system can offer to run an automatic check that will turn on the camera, vibrator, speakers and check the response of the screen.
Often users get here by accident, such as when trying to check the IMEI code *#06# and erroneously enter additional characters, or after a failed reset to the factory settings, when the system sticks during the initial diagnostic stage. In some cases, especially on global firmware versions, the presence of this menu may indicate that the phone was originally intended for the Chinese market and was reflashed.
How to Sign in and Out of the CIT Menu
There are several ways to activate the diagnostic mode, but most of them require the introduction of special USSD-The most common and secure method is to use engineering code that runs on most Xiaomi, Redmi and other devices. POCO.
To enter, you need to open the dialer (caller) and dial the following combination:
##6484##Once you enter the last star or number, the menu should open automatically. If the code didn't work, you can try an alternative way through the settings, but it's not available on all versions of MIUI. To do this, go to Settings → About Phone → Version of the kernel and quickly click on this 5-7 times. The CIT menu will open, where you can choose manual or automatic test.
☑️ Checking before entering CIT
To exit the mode, you usually just press the back or home button, and then select Exit or Back at the bottom of the screen. If the interface is locked and the buttons do not respond, try pressing the power button on the back. 10-15 In the rare cases where the phone is stuck in a test cycle, retrieval and re-insertion helps. SIM-map.
⚠️ Warning: Do not try to change the parameters in the engineering menu unless you know exactly what they are responsible for. resetting the sensors calibration or changing the frequencies of the processor can lead to malfunction of the device.
Transcription of the main tests in the list
The CIT mode interface is a numbered list. Each item corresponds to a specific module of the smartphone. Understanding what each line means will help you quickly diagnose the problem. For example, if you have a sound that is not working, but you do not know whether it is a speaker or a software glitch, the speaker test in this menu will give an accurate answer.
Here are the main categories of tests you will encounter:
- 📱 Version: Displays full information about the firmware version, device model and hardware identifiers.
- 🎨 Color: Display test. The screen is filled in red, green, blue and white to check for broken pixels and uniformity of backlights.
- 🔊 Receiver & Speaker: Check the speaker (ear) and the main speaker. You will hear a characteristic noise or melody.
- 📳 Vibrator: Short-term vibration of the motor test device.
- 📡 GPS: Launch of the navigation module to check the reception of satellites.
Also on the list are often tests for Front Camera (front camera), Back Camera (main camera), Touch Panel (multi-touch check) and Sensors (accelerometer, gyroscope, proximity sensor), which can be used to determine with high accuracy which component needs to be replaced.
What does the Key test mean?
Automatic and manual diagnostics
CIT offers two scenarios: automatic running of all tests and manual checking of individual modules. Automated mode is convenient if you want to get a quick general condition of the device, but it takes longer. The system will switch the colors of the screen, turn on the camera, check the sensors and give a final report.
Manual mode gives you more control. You can choose what to test. This is especially useful for diagnostic (floating) malfunctions. For example, if the phone sometimes loses the network, you can run a radio test several times in a row to catch the moment of failure. In manual mode, you can check the Touch Panel in detail, drawing lines throughout the screen to find areas where the touch screen does not respond.
When passing tests, the system marks the results: usually green or Pass means that the component is working, and red or Fail means that an error is detected, but it is worth considering that software tests can not always detect physical defects, such as microcracks in the board, which manifest only when the case is bent.
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The automatic test is convenient for quick checks, but the manual mode allows you to study the behavior of a particular sensor or module in real time.
Error table and their significance
During the diagnostic process, you may encounter various error messages, and here is a table that will help you interpret the most common test results in CIT mode.
| Name of the test | Status | Possible cause |
|---|---|---|
| Touch Panel | Fail | Failure of touchscreen, plume or calibration |
| GPS | Timeout | No signal (you need to go outside) or antenna module |
| Camera | Open Fail | The camera is busy with another process or physically disabled |
| SD Card | Not Found | The card is not inserted, damaged or the slot is oxidized |
| Sim Card | Invalid | SIM reading problems, contact contamination, or modem failure |
If you see Fail status on a critical module, such as a camera or touchscreen, it is a sure sign of the need to contact the service center. However, if the error appears only when the test is first run, try restarting the device and checking again. MIUI Sometimes they can give false positive results.
Why did the phone enter CIT?
When Xiaomi handsets start CIT mode on their own, there may be a few problems: First, it could be a sticky button. Often, a key combination to log into an engineering menu or a recovery mode is associated with volume buttons. If the button hits or gets dirty, the phone perceives this as a command to start the diagnosis.
Second, it could be a file system failure or system files that are damaged after a failed update, in which case the bootloader can't start the operating system properly and goes into hardware check mode, and this happens after a Hard Reset, when the phone performs an initial hardware check before the first boot.
⚠️ Note: If the phone is included in CIT cyclically (after rebooting, it is re-introduced) CIT), Check the volume buttons. Try tapping the body gently around the buttons or cleaning them with compressed air.
In rare cases, poor assembly or moisture gets into the case, causing the contacts to close on the board. If simple methods like rebooting and cleaning the buttons do not help, the motherboard is likely to malfunction.
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If the volume buttons are stuck, try pressing them several times quickly to develop a mechanism, or gently tuck the edge of the button (if the design allows) to release.