Owning a modern Xiaomi smartphone opens up access not only to basic features but also to hidden diagnostic tools that are usually hidden from the eyes of the average user. CIT (CIT Test is a special software module designed to test hardware components and check the system parameters of the device. It is through this interface that specialists of service centers conduct primary diagnostics when accepting the gadget for repair or after replacing the display and battery.
For a regular Redmi owner, accessing this partition can be a lifeline in situations where the phone stops seeing. SIM-A card that doesn't work properly, a sensor or microphone, and unlike standard Android settings, a hidden interface allows you to work at a lower level, bypassing the software limitations of the shell. MIUI However, using these tools requires caution, since changing critical parameters can lead to unstable operation of the operating system.
In this guide, we will take a look at all the known ways to log into the engineering menu, review the main sections for checking the hardware, and answer frequent questions users have when trying to activate hidden functions, learn how to check the IMEI, calibrate the proximity sensor, and diagnose problems with the communication module without going to the service center.
What is an engineering menu and why it is needed
The engineering menu on Xiaomi smartphones is not just a setup list, but a full-fledged diagnostic package built directly into the device’s firmware, and its main task is to ensure that every single component of the phone can be checked, from the vibrator and speakers to Wi-Fi and GPS modules. Developers use this tool in the factory for quality control, but it remains accessible to end users, which is a hallmark of the Android platform.
One of the main functions of this section is to verify IMEI If you lose your connection to the network or if you have a "No" sign. SIM-This is where you can see if the modem recognizes the inserted SIM at the hardware level. In addition, through this interface, the sensor is often calibrated after changing the glass or display, which is not possible through the standard settings menu.
⚠️ Note: Making changes to network settings or flashing the modem through an engineering menu without proper qualification can lead to complete loss of cellular signal. Use only the Test function, avoiding Write or Set partitions if you are not sure about your actions.
In addition to diagnostics, this tool is useful for authenticating the device. If you see empty fields or no tests for certain modules when you enter the menu (for example, a camera or fingerprint sensor), this may indicate poor build or use of non-original components during repairs. Bluetooth debugging and reset battery usage statistics are also available for advanced users.
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Before selling a smartphone, be sure to conduct a full test of all functions through the engineering menu - this will increase the trust of the buyer and confirm the serviceability of the device.
The main ways of entering through USSD-code
The fastest and most common method of activating a hidden interface is the use of special combinations of symbols, the so-called “Symbols”. USSD-These commands are telephony-level, and they don't require an Internet connection or a superuser (Root) right, so just open the phone app, go to dial and type in the sequence of characters.
For most Redmi and Poco models, the following codes are relevant, which should be entered in full:
- 📱 ##6484## is the main code for entering the full code. CIT Menu available on 90% of Xiaomi devices.
- 🔧 ##4636## is the standard Android test menu that displays information about the battery, usage and statistics of Wi-Fi.
- 📶 ##726633## - an alternative code for entering the equipment testing menu (works on older versions) MIUI).
- ℹ️ *#06# – Quickly call information about IMEI (It works even if the phone is locked).
It is important to note that on some global firmware versions, telecom operators may block certain implementations. USSD-If you don't enter the code, or if you get a connection error message, try using the second method through your system settings. Also make sure you enter the code in the call app, not in the desktop search bar.
Alternative login through system settings
If codes are not available for some reason or are blocked by an operator, Xiaomi has provided a workaround through the GUI, a method that is particularly relevant for newer versions of HyperOS and some regional firmware where direct commands can be filtered, and the login process takes a little longer but guarantees results.
To activate the test menu, follow the following steps:
- Open the Settings app on your smartphone.
- Go to the section About phone (About phone).
- Find the Kernel version or the MIUI version.
- Quickly click on this line 5-7 times in a row.
After a series of clicks, the system will automatically redirect you to the interface. CIT Test. Here you'll see a list of all the modules available to test, and it's convenient because it doesn't require you to remember digital combinations, and it works even when the phone module is temporarily unresponsive. USSD-requests due to software failures.
☑️ Check before entering the menu
Review of main sections and testing of components
Once you log in successfully, you will find a list of tests that are responsible for each specific node of the device. The interface is usually minimalist with the Pass and Fail buttons. Below is a table describing the most important sections that should be checked first when buying a used device or diagnosing malfunctions.
| Name of the test | Function | What to check |
|---|---|---|
| Version | Information on the system | Android version, MIUI, serial number, IMEI. |
| Touchpanel | Sensor diagnostics | Uniform response, presence of "dead" zones, multi-touch. |
| Receiver | Speaking speaker | The presence of sound, the absence of wheezing and distortion. |
| Vibrator | Vibromotor | Vibration force, no rattling of the body. |
| Proximity | Approximation sensor | Reaction to the hand (the screen should go out). |
The Touchpanel test is a test that you're going to run, and you're going to have to swipe your finger over the surface, and it's going to show you where the sensor doesn't respond to touch, which is often the case after poor-quality glass changes, and the Proximity test is critical, because if the sensor doesn't work, the screen won't go out during a conversation, which will lead to accidental cheekstrokes.
Version provides detailed memory configuration information (RAM/ROM) to check if you've been upgraded to a cheap version of your phone by software, and if the amount of storage in the marketing materials is not the same as the engineering menu, you've got a modified device.
Hidden camera tests
Diagnosing problems with SIM-map-and-net
One of the most common reasons for using the service is the loss of a network or the inability to register with the operator's network. The engineering menu provides advanced tools for working with the radio module that are not available in the normal interface. Using the code # #4636##, you can access the Phone Information menu, where the real strength of the signal in dBm is displayed.
For example, if the phone is stuck on 2G (EDGE) and does not want to catch 4G, you can try to manually choose the preferred network type. However, here lies the main risk: installing the wrong mode (for example, LTE Only on a device without VoLTE support from the operator) can lead to the fact that you will be left without incoming calls, since voice communication in 4G mode only without VoLTE does not work.
⚠️ Attention: The "Ping test" feature in the network testing menu allows you to check the availability of Google servers. If the ping does not pass, the problem may not be in the SIM card, but in the settings. APN (access point) or operator lock-in.
Also available in this section is a "Refresh" or "Turn off radio" button that restarts the radio module, which is equivalent to turning flight mode on and off, but is performed at a deeper level, often helping to "hook up" the network in areas of uncertain reception, where the usual network reboot is not coping.
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Forced network type change can temporarily improve reception, but Auto mode is recommended for continuous use so that the phone can switch between communication standards when moving.
Frequent errors and methods of their elimination
Despite the simplicity of the interface, users often face situations where menus fail to open or tests fail. One common problem is that the user is unable to press the Pass button in some tests. This may be because the test requires physical interaction (e.g., close the proximity sensor) that the user did not perform.
If the codes don't work and you give a message "Code is invalid" or just reset the set, check if the "Developer For" mode is activated with USB debugging disabled, although this rarely affects CIT. Sometimes the problem lies in third-party applications that intercept the dial, in which case try temporarily installing a standard Google call.
In rare cases, especially on re-stitched devices (Global ROM in Chinese), the engineering menu section may be stripped or missing altogether, due to differences in hardware and software, and if you're faced with this situation, the only way to restore full functionality is by flashing it back to your home region.
- 🚫 Login error: Code is dialed but menu does not appear – try entering the code without pressing the call button, it must run automatically.
- 📉 False test failure: Dynamic test fails - increase media volume to maximum before running the check.
- 🔋 Discharge: Some tests (such as screens) quickly land the battery - plug the charger in before a long diagnosis.