CIT Test on Xiaomi: a complete guide to smartphone diagnosis through the engineering menu

If you have ever experienced a problem on a smartphone Xiaomi, Redmi or POCO, You've probably heard of the mystery. CIT Test is a diagnostic tool hidden in the bowels of the engineering menu, which tests the performance of key components of the device, from the display and sensors to communication modules and battery. But how to run it, what the indicators mean, and when it is really worth resorting to this feature?

Unlike standard tests like #4636## (for Android), CIT Xiaomi Test gives deeper analysis of hardware, including verification NFC, Gyroscope, Barometer and even IR However, not all users are aware that misuse of this tool can lead to resetting or locking the bootloader — especially on devices with an unlocked bootloader. CIT Test, decipher its results and explain in which cases it is impossible to do without it.

What is it? CIT Testing for Xiaomi and why you need it

CIT The Customer Inspection Test is a built-in diagnostics tool that manufacturers (including Xiaomi) use to test devices during manufacturing and maintenance, unlike public tests like Mi Check (available in Settings). → The phone), CIT Test gives you access to low-level parameters that are usually hidden from the user.

The main tasks of the utility:

• 🔍 Diagnostics of hardware faults – checking the display for broken pixels, testing cameras, speakers, microphones and sensors.
• 📡 Analysis of communication modules - assessment of the signal Wi-Fi, Bluetooth, GPS and cellular networks (including support) 5G compatible).
• 🔋 Battery control – measuring the actual capacity, charging cycle and battery temperature.
• 🛠️ Post-repair check – confirmation of the operability of the replaced components (for example, after replacing the screen or motherboard).

It is important to understand that CIT Test is not a magic wand for repairs; it only detects problems, but it doesn't fix them. For example, if a test shows a Camera Failed error, it means that the camera module is faulty or poorly connected, but it will require physical intervention to fix the cause.

⚠️ Note: Some Xiaomi models (especially those with MediaTek processors) launch CIT Test could lead to reset IMEI This is true for devices with unofficial firmware or unlocked bootloader. Before testing, make sure you have a backup of the data.

How to launch CIT Test on Xiaomi: step-by-step instructions

There are two main ways to activate CIT Test: through the engineering menu (for Qualcomm processors) and using codes USSD (For MediaTek, let's look at both.

Method 1: Using the Qualcomm Menu

This method works for most Xiaomi, Redmi and other smartphones. POCO Snapdragon chips (e.g. Xiaomi 12 Pro, Redmi Note 11 Pro)+, POCO F4).

1. Open the Phone app and type the combination: ##4636## This will open the Testing menu (some firmware may require entering ##2486##).
2. In the window that appears, select CIT (If you don't have one, try the alternative code: ##284##
3. A list of tests will appear on the screen. For a full diagnosis, click Start All Tests (or select individual components manually).

Method 2: Through codes USSD (MediaTek)

Devices on MediaTek processors (e.g. Redmi) 10C, POCO M4 Pro) often require other combinations. Try the following codes:

• #36446337## is the main engineering menu.
• ##2846579## → Project Menu → Background Setting → CIT Test.
• #284## - Direct access to the tests (not working on all models)

If none of the codes worked, it could mean that:

• 🔄 The firmware of the device is modified (for example, custom installed) MIUI or LineageOS).
• 🔒 Manufacturer has disabled access to the engineering menu (relevant for some regional versions).
• 📱 The device is too new and the codes have changed (for example, on Xiaomi 13 Ultra or Redmi Note 12 Pro).+).

adb shell am start -a android.intent.action.MAIN -n com.android.settings/.DevelopmentSettings

This will open the developer’s hidden settings where a partition is sometimes available. CIT.-->

Transcription of results CIT Test: What Errors Mean

After the test is completed, you will receive a list of components with statuses. PASS (successfully FAIL (Below is a breakdown of the most common errors and their possible causes.

Particular attention should be paid to errors associated with the Baseband (modem) and IMEI. If the test shows a Baseband Unknown or IMEI Null, that could mean:

• 📶 Losing. IMEI After firmware (recovery with Mi Flash Tool).
• 🔌 Damage to the modem chip (requires rations or replacement of the motherboard).

When to use CIT Test and when not

CIT Test is a powerful tool, but it's not universal. Here are some cases where it's justified:

• ✅ After a fall or impact – to check the display, accelerometer and gyroscope.
• ✅ Before buying a used device - to make sure that all modules are working.
• ✅ After replacement of components (e.g. battery or camera).
• ✅ Suspected hardware failures (spontaneous reboots, lack of network).

Here’s when you should not take this test:

• ❌ To solve software problems (e.g., glitches) MIUI In this case, resetting settings or flashing the firmware will help.
• ❌ On devices with unlocked bootloader without backup IMEI.
• ❌ If you do not understand the results, it is better to contact the service center.

⚠️ Note: Some Xiaomi models (e.g. Redmi) K50 or POCO X4 Pro) multiple launches CIT Test can lead to the activation of Anti-Rollback, a protection mechanism that blocks the firmware rollback, which can "brick" the device if you planned to downgrade.

Alternatives CIT Test: Other ways to diagnose Xiaomi

If CIT Test is not available or its results are unclear, alternative methods of checking the device can be used.

1.Inline MIUI tests

V MIUI There is a standard tool for checking the display and sensors:

1. Go to Settings → About the phone → All the parameters.
2. Click several times on the kernel version (or version) MIUI), until the test menu is available.
3. Select the desired component (for example, Touch Screen Test or Camera Test).

Third-party annexes

For a deeper diagnosis, utilities from Google Play are suitable:

• 📱 CPU-Z — Shows detailed information about the hardware (processor, memory, sensors).

3. Diagnosis through ADB

Teams are available for advanced users ADB, This allows you to check individual components:

• Adb shell dumpsys sensorservice
• Adb shell service call SurfaceFlinger 1008

The advantage of these methods is that they don't require access to an engineering menu and are safe for the device, but they're less accurate than that. CIT Test, and do not always reveal hidden faults.

💡

CIT Test is the most reliable way to diagnose, but it requires caution. If you are not sure about your actions, use alternative methods or contact a service center.

Frequent errors in use CIT Testing and how to avoid them

Even experienced users sometimes make mistakes when working with the Internet. CIT Test. Here are the most common ones and how to prevent them:

1. Starting the test on the discharged battery

If the charge level is below 30%, the device may shut down during the diagnosis, which will result in:

• Loss of unsaved data.
• Failure of sensors (for example, a gyroscope may start to “glutch”).
• In rare cases, damage to the file system.

Solution: Always charge your smartphone to 50% or higher before testing.

2. Ignoring discharge warnings IMEI

On devices with MediaTek (e.g., Redmi) 9A or POCO C31) launch CIT Test can reset IMEI It's going to zero, and it's going to make the smartphone unusable for calls and mobile Internet.

Solution: Preserve before testing IMEI (You can find it on the box or in the About phone settings. → General information and use tools like Maui META repair.

3. Interrupting the test manually

If I have to interrupt. CIT Test (for example, by pressing Back or pulling out the battery), this can lead to:

• The device hangs on the logo MI.
• Loss of sensor calibration (e.g. automatic brightness).

Solution: Wait for the test to be completed or restart the device via Press the power button for 10 seconds.

4. Use on informal firmware

On custom firmware (e.g. Pixel Experience or Havoc) OS) CIT The test may work incorrectly or may produce false errors.

Solution: Return to the official MIUI Mi Flash Tool if you need accurate diagnostics.

FAQ: Answers to frequent questions about CIT Testing for Xiaomi