Xiaomi’s modern smartphones have powerful hardware, but the standard settings are often lacking to accurately diagnose their state. The Engineering Menu is a hidden software interface designed for developers and service engineers that gives access to deep testing of all components of the device. This is where you can conduct detailed checks of the display matrix, sensor calibration, test microphones and speakers, and access hidden communication parameters.
Many gadget owners are eager to get into this section not only for repairs, but also out of pure curiosity, wanting to learn more about their device. However, careless handling of certain features can lead to resetting important parameters or even software errors. In this article, we will discuss in detail how to securely log into the CIT (Customer Interface Test), look at the basic codes and explain what the key sections of testing are responsible for.
Before you go into action, it is worth understanding that the interface may differ slightly depending on the version of the MIUI shell or the new HyperOS. Despite the visual differences, the logic of the operation and the set of basic tests remain almost identical on most models, from the budget Redmi series to the flagship Mi. Below are current methods for accessing hidden functionality.
What is the engineering menu and CIT on Xiaomi smartphones
CIT is a specialized set of tools to check the hardware of a smartphone. Unlike the usual settings menu, where the user changes the software settings, there is a direct interaction with the hardware, which allows you to identify faults that are not visible in everyday use, such as broken pixels, sticking buttons or problems with the GPS module.
Access to this section is often required when buying a used device. A potential buyer just runs several tests to make sure that the touchscreen and all cameras work. Code ##64663## is universal for Xiaomi devices and works even without a SIM card or with a locked screen (depending on the firmware version).
⚠️ Warning: Changing the parameters in the sections marked as "Engineering" or associated with the calibration of the radio module may cause loss of network signal (Set/Write).
System engineers use this tool to quickly localize the problem, and if you have a sound that's gone, you don't have to bring your phone to the service right away, you can run a test of speakers and microphones, if the test is negative, the hardware problem, if there's sound, it's software or application conflict.
The main ways of entering through dialer code
The fastest and most proven method to get into the testing menu is the use of a special test. USSD-This is a system-level solution that doesn't require any additional software, and you have to open the standard Phone app, go to the dial tab, and enter the character sequence.
The basic code for accessing the CIT is as follows:
##64663##Once you enter the last character of the bar, the number dialer automatically recognizes the command. You don't need to press the call button, you need to go to the menu instantly. If nothing happens after you enter the code, your firmware version may be blocking this method, or the code was entered with an error.
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If the ##64663## code doesn’t work, try the alternative combination ##4636##.It opens up the Android testing menu, which also contains useful battery and usage statistics, although less functional for Xiaomi hardware testing.
There are other codes that can be useful in certain situations, such as ##4636##, which opens up the standard Android test menu, where you can see battery information and usage statistics, but for full diagnostics of screens and sensors, Xiaomi is better to use the basic CIT code.
Entry through MIUI and HyperOS system settings
If the use of codes is not possible or inconvenient for some reason, manufacturers have provided an alternative path through the GUI, which is especially relevant for newer versions of the shell, where security policies may restrict input. USSD-The path may vary a little, but the general logic holds.
To access, follow the algorithm:
- 📱 Open the Settings app and scroll to the bottom of the “About Phone” item».
- 🔋 Find the Kernel version and quickly click on it. 5-7 successively.
- 🧪 The screen will display the menu "version" CIT» Or the list of tests will be opened immediately.
In some versions of MIUI, the path may be different: Settings → Advanced Settings → CIT version. If you don't see this item, try the option with multiple clicks on the kernel version. It's a hidden trigger that activates the diagnostic mode.
The good thing about this method is that it's completely legal and system-supported, it doesn't require code knowledge, and it works even when the touchscreen doesn't respond to some of the characters in the dialing field, but it does respond to fast taps on the menu.
☑️ Checking before entering CIT
A detailed overview of the main tests and functions
Once you go inside, you'll see a list of dozens of items, each one of which is responsible for checking a particular node, and to avoid confusion, let's look at the most important ones that are used most often for diagnostics.
| Name of the test | Function | What we check. |
|---|---|---|
| Red/Green/Blue | Color screen pouring | Broken pixels, uniformity of illumination |
| Touchpanel | Sensor check. | Touchscreen response, multi-touch, dead zones |
| Receiver/Speaker | Sound test | The work of the conversational speaker and the main |
| Front/Rear Camera | Checking cameras | Focus, color reproduction, flash operation |
| Vibrator | Vibration test | Response motor operation |
The Touchpanel test is a test that you're going to run, and when you start it, you're going to be sensitive to any touch, you're going to be asked to swipe around the circuit, or you're going to just drive around the screen, and if the line is interrupted or not drawn in a certain place, that's a sign of a touchscreen malfunction.
Also important is the Receiver test, which is that you can hold your phone to your ear and hear a clear sound, and users often confuse it with the main speaker, but this test is critical to diagnosing hearing problems, and remember to check your microphone by recording your speech and listening to it.
⚠️ Attention: Test «SIM» or Network may temporarily interrupt the connection to the cellular network, and once you exit the test, the connection should be restored automatically, but in rare cases, a device reboot is required.
Hidden opportunities and additional codes
In addition to the main CIT menu, there are other hidden sections in Xiaomi smartphones that can be useful for advanced users, which allow you to access system logs, information about Wi-Fi and more detailed settings of the radio module.
List of useful codes for expanding the functionality:
- 📡 ##4636## — Android Test Menu (battery information, usage statistics, network settings).
- 📶 ##3646633## - MediaTek Engineering Menu (CPU-only devices) MTK, dangerous).
- 🔍 ##225## - Calendar and Event Information.
- 📦 ##7780## - Resetting (caution! can delete data, analogue Factory Reset).
Is MediaTek's menu dangerous?
Using the #4636## code is safe and informative. In the Battery Information section, you can see the actual battery temperature and voltage, which is sometimes more accurate than third-party apps show, and in the Usage section, you can see detailed statistics on running processes.
Frequent problems at the entrance and their solution
It's not always easy to log in to the engineering menu, users may find that the code just doesn't work, or the phone drops a call, most often due to specific features of a particular firmware version or regional restrictions.
If the code doesn’t work, try the following steps:
- Make sure you’re using the original Phone app from Xiaomi or Google.Third-party calls may not support USSD-codes of this type.
- Check if Do Not Disturb mode or specific security settings that block system calls are enabled.
- Try entering the code before delivering it. SIM-In some global versions, this helps activate the menu.
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If none of the codes are working, access to CIT The settings are also blocked, most likely your version of the shell has carrier or region restrictions. ADB-commands to access diagnostics, but it requires a PC connection.
It’s also worth remembering that on the latest versions of HyperOS, the company is increasing security, and some backdoors can close with updates, in which case you can rely only on official diagnostic methods through the settings menu or contact an authorized service center.