FQC Test on Xiaomi devices: a complete guide to diagnosis

You bought a Xiaomi TV or smartphone and stumbled upon a mysterious combination FQC Is the test in the settings menu or the instructions? Or did the device start to glittle and the service center asked to provide the results of this test. FQC (Factory Quality Control is a built-in program for checking hardware components right at the factory and at home.

In this article, we will discuss in detail: what is FQC-A test of which Xiaomi devices it is available for, how to run it (including hidden ways), how to interpret the results, and what to do if the test shows errors. And also – we will answer frequent questions, for example, whether it is possible to reset the test counter or why the manufacturer hides this feature from users.

If you don't. TV Redmi-smartphone began to slow down, show a picture poorly or work with sensors incorrectly — FQC-The test will help to identify the problem in 5 minutes without disassembling the device. But be careful: wrong actions can lead to a lock warranty (for more on this, see the section on risks).

What is it? FQC Test and why you need it

FQC (Factory Quality Control Test is a set of diagnostic tests that go through all Xiaomi devices during the production phase:

• 📺 Screens (broken pixels, backlighting, color reproduction)
• 🔊 Audio systems (dynamics, microphones, connectors)
• 📡 Wireless modules (Wi-Fi, Bluetooth, GPS)
• 🔋 Battery (capacity, charge/discharge)
• 🎮 Buttons and sensors (gyroscope, accelerometer, proximity sensor)
• 🖥️ Ports and connectors (USB, HDMI, 3.5 mm)

In the factory, the test runs automatically on the assembly line, but the manufacturer leaves it to manually run it, because there is a special menu hidden in the firmware. Why is it hidden? Because Xiaomi does not want users to accidentally change critical settings or reset the counters (about them below).

When you need it. FQC-test-house:

• 🛠️ Before selling the device - to confirm its serviceability.
• 🔧 After a fall or impact to check if the components are not damaged.
• 📦 When buying used equipment - to avoid hidden defects.
• ⚡ If the device started to glitches (spontaneous reboots, artifacts on the screen).

⚠️ Attention: Launch FQC-Testing on some Xiaomi models (e.g. Mi) TV 4S/5X) It drops the warranty counter, and if you're planning to bring the device to the service, don't do the test unnecessarily, which can make it harder to repair the warranty.

What devices Xiaomi is available on FQC Test

The feature is built into all Xiaomi TVs (Mi series). TV, Redmi TV, Mi TV A, Mi TV Q et al.), and most of the brand's smartphones and tablets, but the way it launches is different:

On smart watches (Mi Band, Xiaomi Watch) and Xiaomi routers FQC-There is no test – other diagnostic methods are used for them (for example, Mi Fit or Mi Wi-Fi).

If your model is not listed in the table, it does not mean that the test is not. Try universal ways to launch (about them in the next section). FQC deeper, so it may be necessary to unlock the bootloader.

How to launch FQC Test: step-by-step instructions

The method depends on the type of device, and here are proven methods for TVs and smartphones.

For Xiaomi TVs (Mi TV, Redmi TV)

There are three official ways:

1. Through the Settings menu (works on most models): Open Settings → On TV. → Update: Press 5 times in a row on the Mi logo at the top of the screen. Enter password: 123456 or 654321 (depending on the firmware).
2. The button combination on the remote (for older models): Press simultaneously: [Menu] + [Volume Down] + [Power] Hold on. 10 A few seconds before the menu appears.
3. Through ADB (For advanced users: adb shell am start -n com.android.tv.settings/.device.fqc.FqcActivity

If none of these methods worked, try updating your firmware – sometimes Xiaomi blocks access to the software. FQC newer.

For smartphones and tablets Xiaomi

It's more complicated, because the manufacturer is actively hiding access.

1. Code in dialer (works on 60% of models): ##36446337## or #4636## → "Testing of equipment"
2. Through the Engineering Menu: Install the App MTK Engineering Mode (for MediaTek processors) Go to Hardware Testing → Factory Mode.
3. ADB-command (requires unlocked bootloader): adb shell am start -a android.intent.action.MAIN -n com.android.settings/.TestingSettings

Smartphones with Qualcomm Snapdragon (such as Xiaomi 13 Pro) may require special firmware with unlocked options. Be careful - wrong actions will lead to a device blink!

Disable all external devices (configures, sound panels)

Connect the TV to the network (do not use the battery)

Close all applications

Prepare the remote (replace the batteries if necessary)-->

Decoding Results: What Errors Mean

After running the test, you will see a list of components with statuses. PASS (passed FAIL (It didn't pass. That's what the major mistakes mean:

If the test shows UNKNOWN_ERROR, It could mean:

• 🔌 Firmware problems (must be updated).
• 🔧 Maternity board malfunction.
• 🛠️ Conflict with installed apps (try resetting to factory settings).

On Xiaomi TVs after the test may appear the inscription FQC COUNT: X is the launch counter. If it exceeds 5, the service center may refuse warranty repairs because it believes the device has been tested too often.

Frequent problems and their solutions

Even if the test was successful (ALL PASS), The device may continue to glitch. Let's look at typical scenarios:

1.The test passes, but the screen flashes/artifacts remain

Reason: GPU or memory problem. Solutions:

• 🔄 Reflash the device (possibly flew the display drivers).
• 🔥 Check the temperature of the chip (use it). AIDA64).
• 🛠️ If the artifacts are static (e.g., broken pixels) – a physical defect of the matrix, a replacement is required.

2. FQC It shows battery error, but the phone holds the charge.

This is a false positive because of:

• 📉 Battery calibrations (you need to discharge to 0% and charge to 100% without interruptions).
• 🔌 Non-original charger.
• 📊 Failure of the power controller (requires diagnosis in the service).

3.After the test, the sound or Wi-Fi disappeared

The test probably reset the audio or network settings.

• 🔊 For sound: check the settings Settings → Sound. → Additionally. → Resetting the sound settings.
• 📶 For Wi-Fi: Remove the network and connect again, or reset the network settings.

⚠️ Attention: If after FQC-If you've tested the device, it's stopped turning on (brick), don't try to stitch it yourself! 90% of the time, it's a total loss of data. Contact the service with the indication that you've run the factory test, it will help you recover the device faster.

Settings → Annexes → Show it all. → Camera. → Warehouse → Clear the cache

Risks and Warnings: What Can Be Broken

FQC-The test is a powerful tool, but it can be harmful if you use it incorrectly:

1. Reset guarantee counter: On Xiaomi TVs every launch FQC If the meter exceeds 5-10, the service center may refuse free repairs, citing "unauthorized diagnostics".
2. Blocking features: On some smartphones, the test may disable OTA-Update or Google Services (solved by factory reset).
3. Data loss: On Android TVs TV The test can erase user applications and settings.
4. Hardware failure: If you interrupt the test (for example, pull the power cord), it can damage EEPROM (non-volatile memory with device settings).

How to minimize the risks:

• 🔋 Before the test, fully charge the device (or connect to the network).
• 📱 On smartphones, make a backup (via Mi Cloud or Google Drive).
• 📺 On TVs, turn off external devices (configures, sound panels).
• ⏱️ Do not interrupt the test until it is completed (even if it is frozen, wait 10-15 minutes).

💡

If you are not sure of your actions, it is better to contact the Xiaomi service center and ask for a diagnosis officially.

Alternatives FQC Test: Other Diagnostic Methods

If you start FQC Failed or not enough, use alternative methods:

To check the screen for broken pixels, you can use:

• 🎨 JScreenFix (online test).
• 📺 Built-in YouTube video (search for "dead pixel test").

For network problems (Wi-Fi, Bluetooth) suitable:

• 📡 Wi-Fi Analyzer (Signal Analysis).
• 🔗 PingTools (checking connection speed and stability).

FAQ: Answers to Frequent Questions