How to turn off the screen when calling Xiaomi Redmi 9

The situation when Xiaomi Redmi 9 suddenly turns off the display during a conversation, familiar to many owners of budget smartphones. This is not only annoying, but also prevents you from using the speakerphone or checking the number of the interlocutor through the directory. Most often the reason is not a breakdown of the matrix, but incorrect operation of the proximity sensor or software failure of the MIUI shell.

Users often confuse the normal behavior of a smartphone with an error. The proximity sensor is designed precisely to turn off the screen when you hold the phone to your ear, preventing accidental cheek pressing. However, if the screen goes out when the phone is lying on the table or in the hand at a distance, this is a clear signal to action. In this article, we will examine all the ways to solve the problem, from simple calibrations to deep system settings.

Before you start to make complex manipulations, you need to understand the physical nature of the problem. The Redmi 9 uses a software sensor that can conflict with protective films or covers. The sensor's incorrect response causes the system to mistakenly assume that the phone is in the ear, and blocks the image. It is critical to first check if the upper end of the body is covered with foreign objects.

Diagnostics and verification of the proximity sensor

The first step is to pinpoint the source of the malfunction. The MIUI shell on Redmi 9 has an integrated engineering menu to test all components. To get there, open the Phone app and dial the combination ##6484##. This action will trigger the CIT (Customer Inspection Test) mode, where you can check the performance of sensors without third-party software.

In the list that opens, look for the Proximity Sensor. Press it and hold your palm to the top of the screen, then remove it. The indicator on the screen should change the state from Pass to Fail or change color. If there are no reactions or values jump randomly, the problem can be hardware. In some cases, simple cleaning of the sensor area from fat and dust helps.

If the test shows unstable work, try removing the protective glass or film. Thick protective coatings often distort the readings of the infrared emitter. Also check if you have a magnetic case book that can magnetically work the electronics of a smartphone.

⚠️ Warning: Do not use test modes to change parameters unknown to you. Reset the test settings if the results look incorrect before making conclusions about a breakdown.

Calibration of the sensor through the engineering menu

If the physical test is successful, but the screen is still behaving strangely, you need to perform a software calibration, which is a procedure that "explains" the system which values are considered normal and which are a signal of approximation.

In test mode, select Proximity Sensor. You'll see a numerical window. Put your phone on a flat horizontal surface, away from any objects. Press Calibration or Start Calibration. At that point, you can't touch the screen or obscure the top of the case.

Once the process is complete, the system will give you a success or error message. If the calibration is successful, be sure to press the Pass button to save the results, and then exit the menu. Reboot the device will fix the new parameters. Often this procedure returns normal operation to the sensors.

It’s worth noting that newer versions of MIUI may have limited access to full calibration. If the calibration button is inactive or hidden, try using third-party utilities from Google Play, such as “Proximity Sensor Reset/Fix.” They work on a similar principle, asking for the necessary permissions.

Call settings and screen lock

Sometimes the problem isn't with the sensor, but with the settings of the Phone app itself. In Redmi 9, both the standard Google app and the proprietary MIUI Dialer can answer for calls. The settings interface may differ, but the logic remains the same. Go to Settings → Apps → All Apps and find your calling app.

Inside the app menu, look for Incoming Calls or Call Settings. This may include the Approximation Sensor option. If it's active, try turning it off. However, remember that this will cause the screen to burn constantly during a call, which will increase battery consumption. A finer setting is often hidden in the Lock During Call menu.

Also check the system lock settings. Go to Settings → Lock screen. Make sure the Mode in Your Pocket feature is turned off.This mode is designed to prevent accidental taps when the phone is in your bag, but it often conflicts with the proximity sensor, causing the screen to go prematurely.

Using third-party applications to control the screen

If Xiaomi’s regular tools don’t work, Google Play apps come to the rescue, redefining the system priorities of the display. One of the most popular solutions is the Proximity Sensor Fix & Reset app, which automatically triggers the calibration process every time you turn on your phone.

Another option is to use call management applications like Truecaller or Call Assistant, which take over incoming call processing and often have their own, more flexible proximity sensor settings, and installing such an application can completely bypass the bugs of a standard MIUI caller.

However, be careful: installing apps for one feature can lead to conflicts. If you have installed a sensor locker, remove other similar utilities. In addition, such applications require permanent permissions to work in the background, which can affect the autonomy of the Redmi 9.

⚠️ Warning: When installing third-party calls, be sure to provide them with all the permissions requested, otherwise the call may simply not pass or the screen will not go out even in normal mode.

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Try turning off the Smart Response feature in Google Assistant settings, and sometimes the voice assistant will intercept the sensor during an incoming call.

Resetting and system update

Software bugs in firmware are a common cause of hardware instability. If you haven't had updates in a long time, check for them in the Settings menu → About Phone → MIUI version. Developers regularly release patches that fix sensor drivers. Installing the current version of the software is the safest way to solve it.

In case the update didn’t work or the system is already up to date, you can try resetting the Phone app. Go to Settings → Apps → All Apps → Phone (or Google Phone). Select Memory and click Clear → Clear Everything. This will return the call settings to factory settings without affecting your contacts.

A radical but effective method is to completely reset your device. Be sure to back up your data to the cloud or computer before doing so. Resetting to factory settings (Settings → Advanced Settings → Resetting → Erase All Data) removes any software conflicts that may have accumulated during your smartphone use.

After the reset, take your time to install all the apps at once. Check the call on the clean system. If the problem is gone, it means that some third-party application you installed earlier was to blame.

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A clean system installation or a full reset eliminates 90% of the approximation sensor software errors associated with MIUI update conflicts.

Hardware causes and repairs

If neither calibration nor resets helped, there is a high probability of hardware failure. In Redmi 9, the proximity sensor often fails after falls or moisture. Even a microscopic crack in the area of the talking speaker can disrupt the IR emitter.

The problem may also be the plume connecting the board to the top of the case, which is that when you're in active use or poorly assembled, the contact may go away, in which case the screen may go out when you shake the phone or, conversely, not respond to the face.

To diagnose at home, you can carefully (without fanaticism) press the top of the body in the speaker area during the call. If the screen responds to press, then there is a problem in contact. However, to fully repair the device, you will need to disassemble the device and possibly replace the sensor module or plume in the service center.

Frequently Asked Questions (FAQ)