The solution to the problem: the screen does not go out when talking on Xiaomi Poco X3 Pro

The problem of not turning off the smartphone screen during a phone call is one of the most common and annoying for Xiaomi Poco X3 Pro owners. Instead of going out and locking up when you bring the device to your ear, the display keeps glowing.This leads to occasional taps with your cheek or ear, which can interrupt the call, launch a speakerphone or send unnecessary messages to the chat.

The main reason for this behavior is that the proximity sensor is not working properly, and this small sensor, which is located at the top of the housing, is responsible for determining the distance to an object. If the MIUI or HyperOS software receives incorrect data from it, the locking system does not activate, and in this article we will discuss in detail how to diagnose and adjust this component.

You don't have to take your phone to the service center, because most of the time, it's software-based, and we'll look at the standard system settings, the hidden engineering menu for calibration, and how to resolve conflicts with the security film, and calibrating the sensor correctly will bring the comfort of the phone back.

The principle of the proximity sensor in the Poco X3 Pro

The Poco X3 Pro uses a virtual proximity sensor that is often combined with a light sensor. Unlike older physical sensors, here the data is processed by a software algorithm. When you hold the phone to your face, the sensor detects changes in light levels and distance, sending a signal to the Android operating system to turn off the matrix.

If this mechanism fails, the screen continues to burn, which can be due to a software failure in the drivers or after updating the firmware. The system algorithm can misinterpret the sensor readings, believing that the phone is still far from the ear, which is why it is important to adjust the sensitivity correctly.

⚠️ Note: If the screen does not go out due to physical damage (for example, after a fall or moisture), software calibration will not help.

Understanding how this bundle works helps to avoid panic, and more often than not, the sensor simply “forgets” its reference values and requires resetting to factory settings, a standard maintenance procedure for Xiaomi electronics.

Basic settings check and software update

Before you get to the complicated manipulation of the engineering menu, you need to eliminate trivial software errors. Often the problem lies in the bugs of the current version of the MIUI shell. Make sure your device is updated to the latest available version. To do this, go to Settings → About phone and click on the system version.

It's also worth checking if third-party apps block the sensor. Some memory cleaners or call apps can take over the sensor. Try temporarily disabling third-party dialers. The standard call interface from Google or Xiaomi works most stably with the hardware of the device.

Another important point is to clear the cache of the system. Accumulated temporary files can cause conflicts in the operation of services. Go to Settings → Applications → All applications, find Phone and Contacts, then select Clear → Clear cache. This is a secure operation that will not delete your contacts.

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Before calibration, be sure to wipe the top of the screen with a soft cloth.Fat spots or dust can distort the readings of the light sensor, which is used to determine the approach.

Engineering menu: accurate sensor calibration

The most effective way to solve the problem is to use the hidden CIT (Customer Information Test) menu, which is designed to test all components of a smartphone and allows you to recalibrate the proximity sensor, accessed through a special code in the Phone application.

Dial ##6484## in the dialer. The test menu will open. Find the Proximity sensor in the list. You will see a window with two buttons: Calibration and Get Data. You will press Calibration.

Close the top of the screen with your palm, simulating a conversation, and remove your hand. The system will record the new values "close" and "far." After successful calibration, press "Pass" or "Finish." Reboot the device to make the changes take effect. Reboot is mandatory for resetting sensor drivers.

If the Calibration button is inactive or gives an error, try pressing Get Data first to see the current reading. Ideally, when the hand is removed, the value should be 0.0 or close to zero, and when closed, 5.0. If the values do not change, it is possible that the sensor is physically defective.

Influence of protective glasses and covers

Poco X3 Pro owners often face a problem after sticking a new protective glass. If the glass is black bezel around the perimeter or simply too thick, it can block the area of operation of the sensor. Even a minimal offset on the sticker can create a permanent shadow, which the phone perceives as “a touch to the ear” or, conversely, blocks the signal.

It's very easy to test the effect of an accessory. Take off the safety glass or film and repeat the test call. If the screen starts to go out correctly, the problem is solved. In the future, choose glasses with a notch under the speaker or transparent throughout the area. The thickness of the glass also plays a role: too thick shockproof glasses can reduce sensitivity.

And the same thing happens with cases, where if the sides of the case are high and they come on the screen, they can interfere with the sensor, and try to remove the case and check the phone's performance in the naked form, which will help to localize the source of interference.

Diagnosis through ADB and Logging

For advanced users who haven't been helped by standard calibration, there's a USB-built diagnostic method. Connecting your phone to your computer, you can track raw sensor data in real time, and you'll need to install ADB drivers and platform utilities.

Turn on Developer Mode by tapping the build number seven times in the About Phone menu. Then activate USB Debugging. Connect your phone to your PC and enter a command to track sensor logs in the command line.

adb shell dumpsys sensor_service | grep -i proximity

This command will output the current state of the sensor, and by looking at the change in values as you put your hand up, you can see if the system sees the change at all. If the values in the log are dead and do not respond to movement, this is a sure sign of hardware failure or a deep driver failure, and logging helps you determine exactly where the failure is.

Alternative solutions and resetting settings

If neither calibration nor removal of the windows worked, the radical but effective method is a complete reset. This will delete all the data, so make sure to back up. Go to Settings → About Phone → Settings → Erase all the data. This will return the phone to factory status by removing any possible software conflicts.

There is also a Proximity Sensor Fix app in the Play Market that can force the sensor to be calibrated root or ADB. However, on modern versions of Android, its effectiveness is limited without root rights.

⚠️ Warning: Full Hard Reset will delete all your photos, contacts and apps. Make sure you sync your data with your Google account before doing this.

In rare cases, flashing the device through the computer using the Mi Flash Tool helps, which will reinstall the system files cleanly, fixing any damage in the driver partition, but it is a complex process that requires unlocking the bootloader.

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If the screen is still not turned off after a complete reset and flashing, the probability of hardware failure of the proximity sensor is 95%, in which case only replacing the plume or display module will help.

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