The problem of Xiaomi Redmi 8 Pro’s screen going out and refusing to turn on during a conversation is familiar to many users.It’s not always a sign of hardware breakdown or cracked glass; often the failure lies in a software calibration error or touch zone contamination. The proximity sensor is a tiny element that must respond to bringing the phone to the ear, blocking the touchscreen to avoid accidental cheekstrokes.
Owners of MIUI-based devices often find that standard settings are not working properly due to the nature of protective films or covers. If you notice that the person can hear you but you can't see the timer of the conversation, or the screen does not go out, pressing against the ear, you need intervention. We will consider all available methods for diagnosing and manually adjusting the sensitivity of the sensor.
Don't panic if the device behaves strangely after you buy or upgrade the system. In most cases, you can fix the situation without going to the service center using hidden engineering menus or special testing applications. It is important to understand that the accuracy of this component directly affects the comfort of using the phone in voice mode.
Diagnostics and check of sensor performance
Before you start to make complex manipulations, you need to make sure that the problem is the software, not the physical damage. On the Redmi 8 Pro, the sensor is located at the top of the screen, next to the speaker. Initial testing allows you to weed out cases when you need to replace components from simple software failures.
The quickest way to check the status is to use the built-in engineering menu. To do this, open the standard Phone app and type in the special code ##6484#. The screen will display a list of tests (CIT) where you need to find the item "Proximity sensor." When you press it, the system will ask you to close the top of the screen with your palm; if the numbers change from 5.0 (open) to 0.0 (closed), then it is correct.
If the test shows constants or jumps without you, it may indicate a software conflict. Sometimes background apps block access to the sensor. Try restarting the device in safe mode by disabling all third-party programs. If the sensor is working correctly in this mode, then one of the applications you installed is the culprit.
Notice the state of the security glass. Cheap black-framed films often overlap the sensor's workspace, even if it's not visible. In these cases, the system reads the permanent obstacle and locks the screen, preventing the user from completing the call. Removing the protective coating is the first step in fixing the malfunction.
Manual calibration through the engineering menu
The most effective method of solving the problem is forced calibration. Unlike automatic settings, manual mode allows you to “train” the system to respond correctly to the distance to the object, this is especially true for the Xiaomi Redmi 8 Pro, where sensitivity can be lost after drops or replacement of the display.
To enter calibration mode, again, use the engineering menu code ##6484##. Select the proximity sensor test. In the window that opens, you will see the current reading. If the numbers do not change or behave randomly, press the Calibration button. The process takes a few seconds and requires that nothing is in front of the screen.
Once the procedure is complete, the system will ask you to close the sensor with your finger and then remove your hand. Successful calibration is confirmed by the message "Pass" or "Success." If you see "Fail", repeat the procedure 2-3 times, making sure that the room is bright lighting and there are no glares on the screen.
⚠️ Attention: Do not calibrate in bright direct sunlight hitting the screen.Infrared radiation from the sun can knock down the sensor readings and you will calibrate the device incorrectly.
In some versions of MIUI firmware, access to the full CIT menu may be limited to the manufacturer. If the code doesn't work, try entering the ##PROX## command (numbers correspond to letters on the keyboard). An alternative path is sometimes hidden in the Advanced Settings -> Language and Input menu, but it is less common in modern builds.
Using third-party applications for fine-tuning
When built-in tools are scarce, specialized tools from the Google Play Market come to the rescue. The Proximity Sensor Reset/Fix app is one of the most popular tools for forced reboot of the sensor driver. It does not require root rights and works on most Redmi devices.
The principle of such programs is to force the system process responsible for the sensors to stop and restart, and after installing the application, launch it and press the "Fix" or "Reset" button, and the screen can flash, and you will hear an audible signal, which indicates a successful reboot of the module.
There are also applications that allow you to change sensitivity thresholds, such as Proximity Sensor, which allows you to see a real-time graph of the change in values, which is useful for identifying dead zones when the sensor does not respond to a smooth approach of the hand, but beware: changing system parameters can lead to unstable operation.
Make sure you only download programs from trusted developers so you don’t infect your device with malicious code. After using the utility, it is recommended to remove it, since constant background resource consumption is not required.
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Before installing calibration applications, take a screenshot of the current settings or write down the sensor values so you can return to the original state in case of failure.
Set up a set lock in your pocket
One feature that often conflicts with the normal operation of the sensor is "Pack-Block Dial," an option designed to prevent accidental calls when the phone is in your bag or pocket, but on the Xiaomi Redmi 8 Pro, it can cause false positives.
To disable this feature, go to the phone settings. Find the "Block and Protect" or "Passwords and Security" section. In the options list, find "Block dial in your pocket" and move the switch to the "Off" position. This action often solves the problem when the screen does not light up when an incoming call.
Disabling this feature is especially important for users who wear a phone in loose covers or use magnetic accessories. Magnetic fields can be mistaken by the system as a signal to be in their pocket, which leads to a locking of the interface.
If you can't find it in the basic settings, search by settings. Type "pocket" or "lock" into the search box, and the system will suggest the desired section. It's a universal method for all versions of the MIUI shell.
☑️ Checking the lock settings
Resetting and system update
If the software methods didn't work, there may have been a build-up of bugs that prevented the hardware from working properly. Factory Reset is a radical but effective way to do this. Be sure to back up all the important data before you do so, as it will be deleted.
To perform the reset, go to the Advanced Settings menu -> Recover and Reset. Select Settings Reset. The device will reboot and start the cleaning process. Once turned on, the phone will be as new, and you will need to reconfigure the proximity sensor through the engineering menu.
Also worth checking for operating system updates. Xiaomi developers regularly release patches that fix driver bugs. Go to About Phone and click on MIUI. If a new version is available, install it by pre-charging the battery to at least 60%.
⚠️ Warning: When updating your firmware or resetting your settings, make sure the battery is more than 50% charged. Interrupting the upgrade process may cause the device to fail completely (brick).
Often, the problem is solved by simply updating the components of Google Play Services. Go to the Play Market, search for Google Play Services and click Update. This component is responsible for the interaction of many system functions, including sensors.
Hardware causes and physical maintenance
When the software is in good shape, the cause of the malfunction is physical factors. On the Redmi 8 Pro, the proximity sensor is under the display glass. If the phone fell, the plume could move away or the sensor itself could shift, in which case the software calibration will not work.
Pollution on the top of the screen is a common cause of failures. Fat, dust and dirt can interfere with the infrared beam. Wipe the speaker area with a soft microfiber slightly moistened with alcohol. Do not use aggressive chemicals that can damage the oleophobic coating.
If you have recently changed the display or glass, perhaps during the assembly used the wrong glue or loosely pressed the plume. In cheap copies of screens, the sensor can be installed with error or even absent (in such cases, software emulation works through a gyroscope, which is less accurate).
What if the sensor doesn’t work after the screen is replaced?
The table below provides the main symptoms and possible solutions for rapid diagnosis:
| Symptoms. | Probable cause | Method of decision |
|---|---|---|
| The screen doesn't go out when you ring. | Pollution or software failure | Wipe the screen, calibrate it. |
| The screen goes off immediately and does not turn on. | Film or case | Remove the protective glass, check the case |
| Interlocutor hears an echo | Mike/sensor malfunction | Checking in the engineering menu, repair |
| Accidental cheekstrokes | High sensitivity | Turn off the "Blocking in your pocket" |
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If neither calibration, resetting, nor replacement of the protective glass helped, most likely, the problem is hardware in nature and requires replacing the sensor module or plume in the service center.