Owners of Xiaomi, Redmi and POCO smartphones often face situations where standard system settings are not enough to diagnose problems. The service menu (or CIT – Customer Integration Test) is a hidden interface designed to test hardware components of the device in the factory. This is where engineers check the display, microphones, sensors and communication modules before the gadget gets into the hands of the buyer.
Access to these features may be required if you have a proximity sensor stopped working, “broken” pixels appear on the screen, or your phone has stopped seeing. SIM-Unlike the developer mode, the engineering menu allows you to perform hardware tests in real time, displaying raw data from sensors.
In this article, we will discuss all the current ways to enter the hidden parts of the system. MIUI And HyperOS. You'll find out what it is. USSD-The codes are currently working on how to run tests through the standard Phone app and what precautions you need to follow to avoid knocking down important calibrations. Using these tools will help you determine whether the failure is software or if you need a visit to the service center.
What is CIT and what is an engineering menu for?
abbreviation CIT It's not just a setup list, it's a full-fledged diagnostic tool built deep into the Android system, and the main purpose of this mode is to check every component of a smartphone in isolation. When you run a camera test in normal mode, the system can ignore focusing errors, but in the end, the camera is not able to perform a task. CIT-In the resume, any module failure will be recorded as “Fail” (Error).
This tool is not only useful for engineers, but also useful for the average user in the following cases:
- 🔍 Diagnostics of “dead” areas of touch screen after the fall of the phone.
- 🔊 Check the operation of the second microphone (noise reduction), if the interlocutor does not hear you well.
- 📡 Testing of modules GPS Wi-Fi with constant communication interruptions.
- 🔋 Checking the real status of the battery and charge cycles when the indicator shows incorrect percentages.
It is important to understand the difference between a developer menu and a CIT. The first is designed to debug applications and work with ADB, the second is for physical testing of hardware. Interference with calibration parameters (for example, resetting data from an accelerometer or proximity sensor without need) can lead to malfunctioning of the device, which is difficult to fix software.
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Before testing, be sure to charge your smartphone to at least 50%. Some tests, such as checking the vibration or screen, consume a significant resource of energy, and a sudden shutdown can interrupt the diagnostic process.
Basic codes for entering the service mode Xiaomi
The fastest way to get into hidden areas of the system is to use special combinations of characters entered through a standard “caller”. However, it is worth considering that Xiaomi regularly changes the structure of the software in the MIUI and HyperOS updates, so some old codes may stop working.
Below is a table of current commands for different models, enter them carefully, without spaces or additional characters.
| Command (code) | Function/Description | Status of work |
|---|---|---|
| ##6484## | CIT main menu (iron tests) | It works on 95% of devices. |
| ##4636## | Menu of information about the phone (statistics, Wi-Fi) | It's stable. |
| ##7780## | Resetting (Factory Reset) | Requires confirmation. |
| ##34971539## | Information on the camera and | Partial support |
The most important diagnostic code is ##6484##. It opens the full list of tests. If the menu doesn't open automatically after entering the last digit, try pressing the call button (green handset), although in most modern shells the transition is instantaneous. If the code doesn't work, your firmware version may be restricting access to these functions through dialing.
☑️ Pre-code checks
Alternative login via the “Security” app
If standard USSD-codes do not respond, which often happens on global versions of firmware or after major Android updates, there is a reliable workaround. the Engineering menu on Xiaomi can be run through the system application “Security”, which is preinstalled on every device of the brand.
The algorithm is simple enough, but it requires care. Open the Security app, scroll down to the bottom and find Device Information or Special Features. In some versions of MIUI, this section is hidden inside the About Phone menu in the settings, but the path through Security is more direct. Find the Kernel Version or MIUI Version and click on it repeatedly (about 10 times).
After a series of taps, the screen should have a hidden CIT menu, which is good because it doesn't depend on the telephony or the SIM card, it runs the system diagnostic module directly, and if that didn't work, it's possible that the engineering tests are blocked by the carrier or the manufacturer for your particular model.
⚠️ Note: In the menu that is opened by repeatedly clicking on the kernel version, avoid items called Clear eMMC or Format Data. These features are designed to completely flash the device in the factory and will lead to the irrevocable deletion of all your data and the possible lockdown of the bootloader.
Detailed diagnostics of hardware components
Once you've successfully logged in, you'll see a long list of tests, each item corresponding to a specific node on your smartphone, and you'll usually need to click on the name of the test, then click on the "Start" or "Next" button, and the system will tell you what to do: hit the sensor with your finger, press the volume button, or just look at the screen.
Special attention should be paid to the tests that most often reveal real problems:
- 📱 Touchpanel: Touchscreen check. You'll see a grid or a drawing on the screen. You'll have to swipe all the lines. If the line doesn't light up in a certain place, there's a dead zone».
- 👂 Receiver/Speaker: Check the speaker and the main speaker. The phone will produce a series of sounds of different frequencies.
- 🌫️ Proximity sensor: Approximation sensor. Close the top of the screen with your hand, the screen should go out, remove it, it should catch fire.
- 📸 Camera: Focus and color reproduction checks for both cameras.
Test results are labeled as Pass or Fail if you see Fail on a critical component, such as a critical component. GSM-A module or touch screen is a direct indication for a repair, and a software reset rarely helps, because the problem is physical damage or the plume's drift.
Secret battery tests
Working with network information and IMEI
The menu called by the code ##4636## is often called Phone Information, which contains critical technical information about the status of the radio module, and in this section you can see the real signal level in dBm, network type (LTE, 5G, WCDMA) and IMEI status.
For advanced users, network mode switching is available here, for example, if a phone is stuck on EDGE or 3G, you can force LTE Only to be prioritized here. However, this should be done with caution: in LTE Only mode, incoming calls may stop working on some devices if VoLTE technology is not configured.
This block also shows statistics on Wi-Fi usage and services running. If you notice that the phone is running fast on standby, check here if there is a process that is constantly trying to connect to the network. Resetting statistics or restarting the air interface sometimes solves problems with "network catching."
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Changing the settings of the preferred network type (Set Preferred Network Type) can temporarily improve Internet speed in areas of uncertain reception, but return everything as it was after use, so as not to lose the opportunity for voice calls.
Possible risks and precautions
Although the service menu is designed to be diagnostic, it gives users access to functions that can be harmful in unskillful hands, and the main danger lies not in the tests themselves (checking the screen or sound is safe), but in the reset and calibration buttons.
It is strongly recommended not to reset the calibration of the accelerometer or gyroscope without good reason (for example, if the navigator shows the wrong direction of movement). After reset, the phone will require you to put it on a perfectly flat surface and undergo the procedure again. Poor calibration will lead to the fact that the autorotation of the screen and pedometer will work incorrectly.
Also worth mentioning is the risk of “bricking” when using functions associated with eMMC (internal memory).Some menu items may initiate partition formatting. If you interrupt this process or confirm it accidentally, the device will stop booting, and it will be possible to restore it only through paid service tools like MiFlash Pro with an authorized account.
⚠️ Warning: Never try to change the meaning IMEI or MAC-Not only can this software kill the communication module, but it is also illegal in many countries, because these identifiers are unique and tied to the equipment.