How to call the engineering menu on Xiaomi: hidden features of the smartphone

Today’s Xiaomi, Redmi, and POCO smartphones are complex computing systems in which the MIUI or HyperOS shell hides a host of diagnostic tools from the average user. One of the most powerful tools for deep analysis and testing of hardware is the hidden section, often called the “engineering menu” or CIT (Customer Integration Test), which allows you to not only check the performance of all sensors, but also to identify hidden hardware defects that standard methods cannot detect.

Entering this mode requires knowing special combinations or using debugging interfaces, as manufacturers deliberately restrict access to these features to avoid accidental damage to settings. Engineering mode is not just a setup list, but a full-fledged diagnostic center that technicians use in factories before sending a device to stores. Understanding the principles of its operation gives the user an advantage when buying a used device or troubleshooting complex software failures.

There are several proven ways to activate the diagnostic interface, each of which depends on the version of the Android operating system and the specific model of the gadget. Some methods require a connection to a computer, others work exclusively through a set of digital codes in the "caller." It is important to understand that interference with the work of system services carries certain risks, so before starting any manipulations, you need to clearly understand the functionality of each button.

Activation methods through a set of codes

The easiest and most common way to get into the diagnostic section is to use the USSD-You need to open the standard phone application and go to the dialing screen. In the input field, you should dial a special sequence of characters, after which the system will automatically redirect the user to the corresponding menu without the need to press the call button.

The core code running on the vast majority of the brand’s devices looks like ##6484##. Once the last digit () is entered, the call interface should disappear and the screen will show a list of tests. If this code does not work, which sometimes happens on global firmware versions or in new HyperOS updates, you can try an alternative combination ##4636##*, which opens the test menu of the phone information, although its functionality is significantly narrower.

⚠️ Note: Entering codes into the call menu is instantaneous, without confirmation. Be careful when typing characters so that you do not accidentally activate a reset or unnecessary test.

It is worth noting that on some models with a locked bootloader or specific regional settings, the codes may be blocked by the operator or the manufacturer itself. In such cases, the system can simply ignore the input or issue a connection error message. Diagnostic mode through the codes is the fastest way, but it does not guarantee 100% success on all software revisions.

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If the code doesn’t work in the Phone app, try entering it through the standard dial bar called by the call button in contacts or messages, sometimes system restrictions are selective.

Entry through settings and special application

When the secret codes don't activate the interface, the built-in system application comes to the rescue, which is hidden from the user's eyes by default, called CIT or Engineering Menu, and is often installed in the system section of the factory assembly, and can be found by searching through settings or in a list of all installed applications if the system processes are displayed.

To start testing through this method, follow the following steps:

• 📱 Open the “Settings” menu of your Xiaomi smartphone.
• 🔍 At the top of the screen, find the search bar and enter the phrase "CIT" or "Engineering".
• ⚙️ Click on the search result that appears to launch the hidden testing app.
• ✅ If the search doesn’t produce results, go to About Phone and repeatedly click on Kernel, although this method often opens up a developer menu rather than a full one. CIT.

An alternative way is through the Advanced Settings menu. MIUI The item "Engineering menu" is placed in the "Developers" subsection, which is activated by pressing the build number seven times. CIT-The mode is most often available through direct search or codes, as it is intended for service centers, and not for daily use by the owner.

Use of debugging by USB and ADB

For advanced users who need access to deep logs and the ability to control their phone from a computer, there is a method of activation via the ADB debugging interface (Android Debug Bridge), which requires prior preparation: the smartphone must have a developer menu on and activated the USB debugging option, without which the computer will not be able to give a command to start diagnostic services.

The process of running the engineering menu through the console is as follows: first, you need to connect the device to the PC and make sure that the drivers are installed correctly, then you enter a command in the computer command line to run a specific component of the system, most often using the launch of the activity of the main settings menu or a specific test package.

adb shell am start -n com.android.settings/.HardwareInfo

Or a more versatile command to launch CIT-test:

adb shell am start -n com.miui.cit/com.miui.cit.CITActivity

The good thing about this technique is that it works even when the touchscreen is partially non-functioning, allowing you to run screen tests remotely, but it requires you to have an SDK Platform Tools installed on your computer, and the command line gives you direct access to the system without the graphical limitations of the interface, making this a useful tool for repairs.

⚠️ Attention: When working with ADB Be careful with reset commands. Inexperienced use of shell commands can result in system files being deleted or a cyclical reboot of the device.

Functional capabilities of the engineering mode

Once you log in successfully, you'll see a list of dozens of items, each of which is responsible for testing a specific module of the device. The interface is usually ascetic with the Pass and Fail buttons, which are necessary to quickly mark the state of the device by the factory's employees during assembly.

Among the available tests, the following key areas of diagnosis can be distinguished:

• 📡 Communications and antennas: checking the work GSM, LTE, Wi-Fi, Bluetooth and GPS modules, including the received signal level.
• 🖥️ Display and sensor: test for broken pixels, check the accuracy of the touchscreen (line drawing), calibration of the proximity sensor.
• 🔊 Multimedia: checking the main and front speakers, microphones (recording and playing), vibrations and flashes.
• 🔋 Sensors and power: accelerometer, gyroscope, compass, as well as checking the battery charge and temperature of the processor.

The sensor test is particularly noteworthy, and if you click on the appropriate item, you can swipe your finger across the screen, and the system will record every touch, and it's the perfect way to detect dead zones or false positives (ghost presses), which are common after a poor repair or fall, and you can also check the Hall sensor (reaction to a magnetic case) and the fingerprint scanner.

Table of the main tests and their appointment

For ease of navigation on the list of tests, which can number more than 30 positions, it is recommended to navigate their purpose. Not all points are clear the first time, because they have technical names. Below is a table deciphering the most important for the average user checks.

Each test usually requires manual confirmation, for example, when you test for vibration, the phone will vibrate, and you need to press "Pass" if it works, or "Fail" if it doesn't. After you pass all the tests, the device can automatically restart or return to the main diagnostic menu, and the tests you pass are marked in green, which allows you to quickly assess the overall condition of the device.

Resetting calibration and additional functions

Inside the engineering menu or adjacent sections, the sensor calibration reset function is often hidden, especially if the proximity sensor is not working correctly: the screen does not go out during a conversation or, conversely, goes out when you just hold the phone in your hand. In some versions of MIUI, there is a separate item "Proximity sensor calibration" or a button "Calibration" inside the sensor test itself.

The calibration process usually looks like this: you glue the top of the screen (where the sensor is located) with a finger or paper, press the start button, wait a few seconds, then remove your finger and press the button again. The system remembers the light levels and distance, after which the sensor should work normally. If the software calibration does not help, the problem is likely to be physical contamination or breakage of the module.

Also in this section, you can find information about battery charging cycles (if supported by a driver), which is useful when buying a used device. Knowing the real wear of the battery, you can make an informed decision about replacing it. Remember that the engineering menu is a diagnostic tool, not a magic pill for repair, but its data can save you money on unnecessary service.

⚠️ Warning: Do not try to change the values in fields labeled "Write" or "Set" unless you know exactly what they are responsible for. Incorrect values can lead to unstable radio module operation or rapid battery discharge.

Frequently Asked Questions (FAQ)

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Engineering menu is a powerful diagnostic tool that allows you to check the performance of all sensors and modules of the smartphone without installing third-party software.