Owners of Xiaomi, Redmi and Poco smartphones often encounter the acronym CIT in the settings menu or when accidentally pressing a key combination. Many users are frightened to see a list of technical tests, believing that it is a virus or malware. In fact, it is an integrated system tool that allows you to conduct deep diagnostics of the hardware of the device without installing third-party programs.
The Engineering Menu, or CIT, is a hidden section of the MIUI and HyperOS operating system, and its primary function is to test the performance of all smartphone modules, from the screen and touchscreen to communication and sensor modules, which are designed for factory engineers and service center employees, but are accessible to anyone who knows how to activate it.
Using this tool can be extremely useful when buying a used gadget or if you suspect a component is malfunctioning. Unlike conventional benchmark applications, this mode has direct access to hardware and allows you to test each element separately. Understanding how CIT works will help you identify problems that are not visible in normal use.
Purpose and functions of the engineering menu
The main purpose of the CIT section is to quickly and accurately check the components of the device before sale or after repair, and when you enter this menu, you will see a list of all the modules available for testing, and the system allows you to run each of them in isolation to make sure that it is healthy.
For example, you can check if all the pixels on the display display display colors correctly, or if there are “dead” zones, and check the microphones, speakers, vibrator and even a gyroscope. For ordinary users, this is an opportunity to make sure that the Xiaomi store bought is fully functional.
- 📱 Display: checking colors, broken pixels and touchscreen response.
- 🔊 Sound: testing of main and conversational speakers, microphones.
- 📡 Communication: checking the work of Wi-Fi, Bluetooth, GPS and cellular modules.
- 🔋 Power: monitoring battery voltage and charger operation.
It's important to understand that running tests doesn't harm the system unless you manually change hidden parameters. However, some actions, such as calibrating a sensor or resetting a radio module data, may require care. CIT is a powerful diagnostic tool that gives you complete control over hardware testing.
⚠️ Warning: Don't try to change the values in the tests unless you're sure of your actions. Standard start test is safe, but manual calibration can knock factory settings down.
How to launch CIT on a Xiaomi smartphone
There are several ways to get into the hidden diagnostic menu, and the easiest and most reliable method is to use a special code in the Phone app, which works on most Redmi, Poco and Xiaomi models with a MIUI shell.
Open the standard "caller" and dial the combination ##6484##. Once you enter the last star, the menu should open automatically, without having to press the call button. If the code did not work, perhaps your firmware version or device model requires an alternative approach.
☑️ Access check CIT
The second way is if the code doesn't work or the keyboard doesn't respond, and you can go through the device settings, which is a little longer, but it guarantees access to the menu on the current versions of HyperOS.
- Go to the smartphone settings.
- Select the item About the phone.
- Find the kernel version string and quickly click on it 5-10 times in a row.
Once you press it repeatedly, it recognizes the action as a request to enter engineering mode, and the CIT window opens, where you can select the test you want to use. If nothing happens, try pressing faster or make sure you're getting it from the Kernel Version text instead of the Android version number.
Basic tests and description
The interface of the engineering menu is a list of items, each of which is responsible for a specific component. When you select any item, for example, Red or Green for the screen, or Receiver for the speaker, the system will prompt you to run a test. You usually need to press the Start or Pass button.
And the TouchPanel test, which is a test that allows you to test the responsiveness of the screen, and you're asked to swipe a finger on a line or paint over certain areas, and if the line is interrupted or the area is not painted over, the touchscreen is not working properly in that area.
Hidden camera tests
The Vibrator test is also important, and it's a test that measures the strength and the nature of the vibration, and it's useful if you think the vibration response is weaker or if you're rattling, and the Proximity test checks the proximity sensor, which is the sensor that blows out the screen during a conversation.
| Name of the test | Function | What we check. |
|---|---|---|
| Red/Green/Blue | Display. | Broken pixels, uniformity of illumination |
| Receiver / Speaker | Sound. | Purity of sound, presence of wheezing |
| TouchPanel | touchscreen | Response, dead zones, multi-touch |
| Proximity | Sensors. | Responding to the approximation of objects |
| GPS | Navigation | Satellite search, coordinate accuracy |
Each test you pass successfully can be marked as a Pass, which allows you to keep a checkup statistic, but it's not necessary for a one-time diagnosis, but it's important to make sure that the site is functional visually or by ear.
Diagnostics of communication and sensor problems
One of the most common reasons for using the service is communication and sensor problems. In the CIT menu, you can check in detail the operation of Wi-Fi and Bluetooth modules, and the test will show whether the device sees the available networks and can scan them.
For verification GPS-If you run a navigation test, you run a test, and you try to find satellites, and if you have zero satellites in a minute, you might have an antenna or a software failure, and this is especially true for people who use a navigator in a car.
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Before testing your GPS, go out to an open space or go to a window, and indoors, the signal may be too weak to be properly checked.
The light sensor and the proximity sensor often cause "glitches" when the screen does not go out during the call or automatically changes brightness. In the CIT menu, you can see raw data from these sensors. Close the top of the screen with your hand - the values should change.
If the tests show an error, try restarting the device first. Sometimes a software failure prevents the modules from working correctly. If the reboot did not help, and the tests in the CIT fall, a hardware malfunction is likely.
Using CIT when buying a used smartphone
Buying a smartphone with your hands is always a risk, the seller can hide small defects that will surface after purchase, and the CIT menu allows you to conduct rapid diagnostics in 5-10 minutes right at the meeting.
First, check the screen for broken pixels and ghost presses. Then make sure both microphones (main and noise reduction) and speakers work. Often used phones are clogged with dust, resulting in a quiet sound.
- 🔍 Visual inspection: Run color tests to see matrix defects.
- 👆 Touch check: run a touchscreen test over the entire screen area.
- 📸 Camera: Take a test photo and video, check autofocus.
- 🔌 Charging: Check the response to the cable connection (Test Charge).
⚠️ If the seller categorically forbids to check the phone through the engineering menu or resets the settings before the meeting, hiding the story, this is a reason to be wary.
It is also important to check IMEI. The CIT menu often displays information about the modem and radio version, and the IMEI matching on the case, settings, and engineering menu is a sign that the phone was not assembled from different parts ("Frankenstein").
Frequent mistakes and ways to solve them
When using diagnostic menus, users may encounter situations where the test does not start or gives an error, often due to software features rather than a breakdown, for example, some global firmware versions may restrict access to certain tests.
If the ##6484## code doesn’t work, try the alternative method through the settings described above.Cit from the Google Play store, which is a shortcut to running this system menu, may also help, although it may not have the right permissions on newer versions of Android.
In some cases, the test may freeze. If it does, don't panic. Press the power button for 10-15 seconds to force the device to restart. This is a normal situation, and it won't cause data loss.
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The CIT Engineering Menu is a secure diagnostic tool that does not require Root rights and does not void warranty when used correctly.
If tests consistently show an error on a seemingly serviceable device, it may require a firmware update or factory reset, but radical measures should be taken to contact Xiaomi’s authorized service center for professional diagnostics.