Many owners of smartphones based on the Android operating system are faced with incomprehensible menus that open when entering special characters in the phone book. One of the most mysterious and frequently encountered interfaces is CIT Test. This hidden section of the system is not intended for the average user, but for engineers and service centers, but knowledge about it can save your gadget from being purchased if hidden defects are discovered.
The abbreviation CIT stands for Customer Integration Test (customer integration test) or simply Component Integration Test. Essentially, this is a diagnostic tool built into the firmware that allows you to check the performance of each individual module of the device: from the screen and touchscreen to proximity sensors and vibration motor. Access to this functionality is usually hidden from the eyes of the average user in order to prevent accidental changes to critical settings.
In this article we will analyze in detail why this mode is needed, how to access it on different phone models, and how to correctly interpret the test results. Understanding the operation CIT will give you the opportunity to carry out a complete diagnosis of the smartphone yourself, without resorting to the services of paid technicians.
Purpose and principle of operation of the CIT mode
The main task of the mode CIT is a quick and automated check of all hardware components of the smartphone before or after its sale repair. When the device is assembled on the assembly line, the engineer uses this menu to make sure that all parts work correctly and interact with the software without errors. For the end user, this tool becomes a salvation when buying used equipment or in case of strange system glitches.
Unlike standard benchmark applications that load the processor and video card, CIT Test works at a low level of access to the hardware. He can force the camera to turn on, light the flash, activate the microphone, or check the sensor response at every point on the screen. This allows you to identify problems that are not visible in the normal operating mode of Android.
The interface of this menu is usually extremely ascetic: a list of tests with launch buttons and result indicators (Pass/Fail). There are no fancy graphics or detailed explanations, just dry technical data. It is important to understand that you are in Engineering Menuwhere some actions may result in resetting settings or changing sensor calibration.
⚠️ Attention: In CIT mode, do not change settings whose meaning you do not know (for example, battery calibration or IMEI). Incorrect changes may lead to inoperability of communication modules or the need to flash the device.
It is worth noting that the implementation of this menu depends on the manufacturer of the processor and shell. On smartphones Xiaomi, Redmi and Poco this section is most developed and accessible, while on pure Android or devices Samsung access to similar functions may be limited or require other combinations.
How to enter the CIT engineering menu on different smartphones
The method of entering the diagnostic mode directly depends on the brand of your device and the installed firmware. The most universal and widespread method is to use a special USSD code in the Phone application. However, manufacturers often change these combinations for security reasons or to change the software structure.
For most devices based on processors MediaTek and shells MIUI a standard command is used. You need to open the dialer and enter a sequence of characters. If the code is correct, the system will automatically redirect you to the appropriate menu without pressing the call button.
##6484##This combination is the “gold standard” for smartphones Xiaomi, Redmi i Poco. After entering the last asterisk, the dialing window will close and the list of tests will immediately open CIT. If this does not happen, try an alternative option, which is sometimes found on older models: This code often opens the Phone Information menu, which is a simplified version of the engineering menu available on many Android devices, including some Android models. Here you can check battery usage statistics, Wi-Fi data and phone information, but a complete list of hardware tests may not be available.
##4636##This code often opens the Phone Info menu, which is a simplified version of the engineering menu available on many Android devices, including Pixel and some models OnePlus. You can check battery usage statistics, Wi-Fi data, and phone information here, but may not have a complete list of hardware tests.
If the codes do not work, there is a software way to enter through the settings. On devices Xiaomi you can follow the path Settings → About phone → Kernel Version. Quickly clicking repeatedly (5-7 times) on the “Kernel Version” item often opens the same testing menu.
- 📱 Xiaomi/Redmi/Poco: Code
##6484##or clicking on "Kernel Version". - 🔧 Samsung: Code
#0#(opens the service menu, similar to CIT). - 🤖 Pure Android/Pixel: Code
##4636##(limited functionality). - 📞 Universal: Try codes
##3646633##(for MediaTek).
If the codes do not work, make sure that you enter them in the “Phone” application (dialer), and not in the search in settings or instant messengers.
The main types of hardware tests and their transcript
After successfully entering the menu, a list of dozens of items will appear in front of you. Each point is responsible for checking a specific smartphone node. Understanding what exactly a test checks will help you quickly find the problem. The names of the tests may differ depending on the localization of the firmware, but their essence remains the same.
One of the most important tests is TouchPanel (Touch screen). When you run this test, the screen turns a certain color and you are asked to swipe your finger across all areas of the display. The system records the touchscreen response. If somewhere the line is interrupted or not drawn, this indicates a “dead zone” of the sensor, which is a serious defect.
Test Camera (Camera) alternately activates the main and front cameras. It is important not just to see the image, but also to check the operation of autofocus, flash and switching between lenses (if there are several of them). A focusing delay or a black image may indicate problems with the camera cable or module.
The test Vibrator (Vibration motor) is also critical. It vibrates for a few seconds. This allows you to evaluate the force of recoil and the absence of extraneous sounds (rattling), which often happens when the phone is dropped. If the vibration motor does not work, you can skip important notifications in silent mode.
| Test name | What is tested | Normal result |
|---|---|---|
| Receiver | Earpiece speaker | Clear sound without wheezing |
| Speaker | Polyphonic speaker | Loud sound, stereo effect |
| Headset | Headphone jack / Type-C | Connection detection |
| Proximity | Proximity sensor | Reaction to raising your hand |
| LED | Event indicator / Flash | Color flash or blinking |
The test deserves special attention Proximity Sensor (Proximity sensor). It is responsible for turning off the screen during a call when you bring the phone to your ear. In test mode, the sensor values should change when you cover the top of the screen with your palm. If the values do not change, you will have random cheek presses during calls.
Hidden network tests
Some versions of the CIT menu contain GSM/CDMA tests, which allow you to check the signal level and operation of communication modules in different frequency ranges. Be careful: incorrectly setting the ranges can lead to network loss.
Diagnostics of the display and touch layer
Problems with the screen are the most common reason for contacting service after mechanical damage. Mode CIT offers in-depth diagnostics of the matrix and oleophobic coating. The test is usually divided into several substages: checking colors, dead pixels and sensor sensitivity.
At the color testing stage, the screen is sequentially filled with red, green, blue, white and black colors. Your task is to carefully inspect the matrix for spots, highlights, or pixels that are lit in a different color (dead pixels). On a black background, highlights at the edges of the screen, characteristic of low-quality IPS matrices, are especially visible.
Sensor test (Touch) often requires clicking on special targets or drawing lines on a grid. This helps to identify areas with impaired sensitivity. If you are buying a used phone, be sure to carry out this test, since “ghost touches” in normal mode can appear rarely and unnoticed.
⚠️ Attention: If during the sensor test you see that lines are drawn with a delay or are interrupted in certain areas, this is a sign of degradation of the digitizer. Such a screen will eventually stop responding to presses completely.
Some advanced tests allow you to check Multi-touch multitasking. To do this, you need to touch the screen with several fingers at the same time. The system should display all touch points. This is important for games and comfortable image scaling.
A high-quality display in the CIT test should display colors evenly, without blemishes, and the sensor should respond to presses instantly over the entire area, including the very edges of the frame.
Checking audio, communications and wireless modules
The communication capabilities of the smartphone are checked in the section, often called Connectivity or through separate tests of speakers and microphones. Sound diagnostics is divided into checking the main speaker (Speaker), conversational speaker (Receiver) and microphones (Microphone).
When testing the microphone, you will be asked to say something. The system records sound and plays it back, or displays the level of the incoming signal in decibels. This allows you to identify a quiet sound or the presence of constant background/noise that will disturb the interlocutor during a conversation. Often the problem lies in the microphone hole being clogged with dust.
Wireless modules Wi-Fi, Bluetooth and GPS are also checked. The GPS test attempts to determine the device's coordinates. If satellites are not detected indoors, this is normal, but the module itself must be active and try to scan the air. For Wi-Fi and Bluetooth, the ability to turn the adapters on and off is checked.
- 🎤 Microphone: Check the main (bottom) and secondary (top for noise reduction).
- 📶 Wi-Fi: Make sure the adapter sees available networks.
- 📍 GPS: The test may take time, the presence of a “cold start” signal is important.
- 🎧 Headphones: Checking the identification of the headset and the operation of the buttons on it.
A software error in the drivers can show a failure even with working hardware, so a single test failure does not always mean a breakdown.
☑️ Quick connection check
Frequent errors and ways to resolve them
When passing tests, users often encounter error messages. Not all of them are fatal. For example, an error in the test SIM Card may be simply due to the fact that the SIM card is not inserted or is blocked by a PIN code. Error Storage (Memory) may occur if the internal memory is full to capacity.
If the test Accelerometer (Accelometer) or Gyroscope (Gyroscope) produces an error, try placing the phone on a flat horizontal surface and restarting the test. Sometimes calibration is required, which can be done by following the instructions on the screen (for example, turning the phone over in a certain way).
In cases where the test constantly produces a result Fail (Failure) even after a reboot, there is a high probability of a hardware failure. This could be an outgoing cable, oxidation of contacts after moisture, or physical breakdown of a component. In such a situation, software methods are powerless.
⚠️ Attention: Interfaces and available tests may change depending on the Android version and MIUI/OneUI firmware update. If you do not find the described test, check the official documentation for your specific device model.
Sometimes exiting the CIT menu is not possible with the standard “Back” button. In such cases, simply restarting the device with the power button helps. Don't panic if the phone freezes at some stage of the test - holding the power button for a long time usually solves the problem.
Reset calibration
Some engineering menus have an “eMMC” or “Storage Test” option. Running a full memory test can take several hours and is not recommended unless necessary, as it places a high load on the memory controller.
FAQ: CIT Test Frequently Asked Questions
Is it safe for the average user to enter the CIT menu?
Yes, just entering the menu and running tests is safe. The only danger is when changing settings in subsections intended for engineers (for example, changing processor frequencies or battery parameters). If you just run tests (press the start button and see the result), you won't break anything.
Why does the code ##6484## not work on my Xiaomi?
In the latest firmware versions MIUI and HyperOS access to the engineering menu via USSD codes can be blocked by the telecom operator or the manufacturer itself for security reasons. Try an alternative login method through “Settings → About phone → Kernel version.”
What to do if the screen test shows “dead zones”?
If the sensor does not respond in certain areas of the screen, this is a physical defect in the digitizer. There is no way to fix this programmatically. The display module needs to be replaced at a service center. It is not recommended to buy such a phone.
Is it possible to find out the real amount of phone memory through CIT?
Indirectly - yes. Memory tests often show the actual amount of available storage. This is useful for identifying fake smartphones where the volume is programmatically overestimated (for example, 256 GB is shown, but in fact 32 GB), although for an accurate check it is better to use specialized applications such as Device Info HW.
How to exit CIT mode if the “Exit” button does not work?
Usually there is an “Exit” button in the lower left or right corner or "Back" If the interface is frozen, simply hold down the power button for 10-15 seconds to force the device to reboot. This will not damage the data.