Why Xiaomi phone screen goes off when called: a complete guide to elimination

The situation when during a phone conversation suddenly turns off the display, familiar to many owners of smartphones Xiaomi, Redmi and POCO. In a normal scenario, the screen should go out only when you bring the device to your ear, and light up again as soon as you move the phone. However, if the screen turns off immediately after the call begins or does not respond to the distance of the device, this turns communication into torture.

The main reason for this behavior is that the proximity sensor is not working properly, and this little sensor, which is located at the top of the body, often takes a finger, a protective glass, or even dust for your ear, and the MIUI or HyperOS system gets a false signal and locks the display to save energy and prevent accidental cheekstrokes, and sometimes the problem lies deeper, in a software failure or a conflict of system applications.

In this article, we will discuss all possible causes of malfunction in detail and offer step-by-step solutions. You will learn how to calibrate the sensor, turn off unnecessary functions and understand when you need to intervene in the service center.

Mechanism of the proximity sensor and main failures

The proximity sensor is an infrared sensor that measures the distance to an object. On Xiaomi smartphones, it is often combined with a speaker or hidden under the screen in models with Virtual Proximity Sensor technology. When you start a conversation, the system polls this sensor several times per second. If an object is fixed closer to 2-3 centimeters, the screen is locked.

The problem is when the calibration gets confused, the sensor can "think" that the object is close even if the phone is on the table, this often happens after a device falls, moisture gets in, or a poor-quality display change, and in software terms, the proximity module is responsible for the operation of the sensor, which can conflict with shell updates.

Special attention should be paid to protective films. If you recently pasted a thick protective glass or film with a black frame covering the top of the screen, this is guaranteed to lead to false positives. The light from the IR emitter reflects off the film material and returns back, creating the illusion of an obstacle.

⚠️ Note: If you recently changed the screen in an informal service, the problem may lie in the lack of heat pad between the sensor and the case or in poor-quality module assembly.

Understanding the physics of the process helps diagnose the problem more quickly, and if the screen goes out chaoticly, it's probably the software, and if it goes out always in the same position or at a certain angle of inclination, it's a hardware malfunction or an accessory problem.

Software calibration of the sensor through the engineering menu

The most effective way to fix a software failure is to recalibrate, and the MIUI and HyperOS shells have a hidden engineering menu, which allows you to reset the current sensor values and write down new ones that are relevant to your device.

You don't need a superuser to log in to the diagnostic menu, just open the standard Phone app and enter a special code. Once you enter the last digit, the menu will open automatically. Find the Single-item Test or just the Proximity Sensor item in the list.

The calibration process usually looks like this: you close the top of the phone with your palm, wait for the reading to change (usually from 5.0 to 0.0), and then remove the hand. The system will fix the minimum and maximum values. Finish the test with the Pass or End button.

It is important to perform this procedure in bright light, but not in direct sunlight, which can distort the IR sensor readings. If after calibration the problem persists, try repeating the procedure 2-3 times in a row. Sometimes the system requires several cycles to correctly record parameters.

System settings and sensor lock

Modern versions of Xiaomi firmware have a feature that allows you to programmatically ignore the proximity sensor, which is a temporary solution that will help you comfortably end a conversation if you don't have time to repair it, but it is not recommended to use this method constantly, since during a conversation with your cheek you can accidentally press the reset button.

To activate this feature, go to call settings. The path may vary depending on the Android version, but most often it is at: Settings → Apps → Settings → Calls → Incoming calls. Here you need to find the "Approximation Sensor" or "Approximity Lock" switch and turn it off.

It’s also worth checking the theme settings. Some third-party themes downloaded from GetThemes may not work properly with the system call dialog boxes. Try switching to a standard Classic or Default theme and checking if the problem has gone away.

Remember, after the system update, the settings may reset to factory settings. So if after the MIUI update, the screen starts to go out again for no reason, the first thing you do is check this menu section. It takes less than a minute, but often solves the problem.

Effects of accessories and physical damage

Physical factors are responsible for more than 60 percent of all sensor problems. As mentioned, black-edged security glass is the sensor's main enemy. The black frame absorbs or reflects IR radiation, preventing it from going out, and the sensor thinks it's a solid barrier, and it turns off the screen.

And pollution also plays a huge role, because fatty ear stains, mesh dust, speaker, or glue residue from an old film can completely block the sensor, and regular cleaning of the top of the screen with microfibre and isopropyl alcohol can do wonders.

If you're using a high-sided case, make sure it doesn't cover the area around the speaker, even a millimeter-high plastic protrusion can create a shadow for the sensor, remove the case and check the phone's naked.

• 🧼 Clean: Wipe the top of the screen with an alcohol napkin, paying attention to the area above the speaker.
• 🛡️ Protection: Remove the black-framed protective glass if it overrides the sensor.
• 📱 Case: Check if the case presses on the edges of the screen, creating a micro-bending matrix.

If the device fell, the plume connecting the lower board to the upper board, where the sensor is often soldered, could be damaged. If the phone fell and the problem appeared immediately after that, software methods are unlikely to help - you will need diagnostics in the service.

Table: Comparison of methods of solving the problem

To make it easier for you to choose the right method of troubleshooting, we have systematized the methods by their effectiveness and complexity. Not all methods are suitable for every situation, so go from simple to complex.

And you can see from the chart that you always start with hygiene and accessories removal. It's free and safe. Calibration is the next logical step. And only if it doesn't work, you have to think about radical measures like resetting or repairing.

Radical measures: Resetting and reflashing

If the software failure is deep in the system, only a complete reset will help.Be sure to back up all contacts and photos before doing so, as the phone's memory will be cleared. Go to Settings → About Phone → Reset and select "Erase All Data."

In rare cases, the problem lies in the specific version of the MIUI firmware. If you have a global version, you can try to switch to Chinese (for power users) or roll back to a more stable version through Fastboot mode.

💡

Before resetting, try simply removing the Phone and Google Play service updates. Often, the conflict occurs after auto-update system components.

Updating to the latest version of the system can also include patches that fix sensors. Check for updates in the Settings → About phone menu. Sometimes Xiaomi releases hot fixes for specific models that solve sensor problems.

Hardware malfunctions and repairs

When all software methods are exhausted, there is Hardware. In Xiaomi smartphones, the proximity sensor can be built into the display plume, in the lower board, or in a separate module at the speaker. In budget models (Redmi series), it is often placed on a flexible button plume.

Signs of hardware failure: the screen goes out even if you don't touch the top of the phone; the sensor doesn't respond to the hand when tested in CIT; the screen shows artifacts in the top zone, in which case only a replacement part will help.

The cost of repairs is usually low unless you need to replace the entire display. Service centers often change only the plume or the sensor itself, which is cheaper than a full screen replacement. Don't try to disassemble the phone yourself if you don't have experience, as it's easy to damage fragile plumes.

⚠️ Attention: Self-replacement of the sensor on models with screens AMOLED (Xiaomi Mi 11, Redmi Note 10 Pro are extremely dangerous due to the risk of damage to the matrix when peeling off.

If the phone is under warranty and you do not see external damage (cracks, traces of water), safely carry it to an authorized center.

💡

90% of the problems with the fading screen are solved by removing the protective glass or recalibrating in the engineering menu.

Frequently Asked Questions (FAQ)