The situation of Xiaomi smartphone not turning off the display during a phone conversation is familiar to many users: You hold the phone to your ear, but the screen continues to burn, the cheek resets calls or opens unnecessary tabs. It's not just an annoying bug, it's a potential privacy and battery problem. The proximity sensor is exactly the component that is responsible for locking the screen at the right moment.
The reasons for this behavior can be completely different: from banal dirt on the dynamics to complex conflicts in the software of the MIUI shell or HyperOS. In some cases, the culprit is a poor-quality protective glass that covers the sensor. Below we will discuss in detail all possible scenarios and ways to eliminate them.
You don't have to take the device to the service center right away. Most of the time, you can solve the problem yourself by setting up the system or simply manipulating the case. It's important to understand that the touch screen and the light sensor are different modules, but they work together when you make calls. Let's figure out how to make them work properly.
The principle of the proximity sensor on Xiaomi smartphones
The main element that controls the state of the display is the infrared sensor. On modern Xiaomi models, it is most often embedded directly in the speaker of the conversational speaker or located next to the front camera. Its task is to emit invisible light and read the reflected signal. When you hold the phone to your head, the signal is reflected from the surface of the face, and the system receives a command to turn off the touchscreen.
If the screen doesn't go out, the radiation-reflection-system chain is disrupted, which can be due to software delays or physical obstacles. The induction sensor (less common, mostly in older models) responds to magnetic field changes, but today's budget and flagship smartphones are dominated by optical methods.
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If you use a speakerphone or headset frequently, the screen lock feature may not be activated as the system thinks the phone is out of your ear.
It's worth noting that there's a software emulation of this sensor in the MIUI shell, and it tries to predict user intent by analyzing the accelerometer and gyroscope data, but it's software algorithms that often cause failures when the phone doesn't "know" it's in the owner's ear.
Physical obstacles and protective accessories
The most common reason Xiaomi's screen doesn't lock during a conversation is because of external accessories. Owners often forget that the protective glass or film may shift or be initially substandard. If the opaque zone (opaque frame) on the glass overlaps the sensor area, the beam simply won't be able to go out or come back out.
Carefully look at the top of the screen when the display is off. You should see a small dark spot or a slot in the speaker grid. That's where the sensor is. If your security glass has a black frame that even a millimeter enters that area, the problem is guaranteed. Also, dirt, greasy spots or dust in the speaker grid can block IR radiation.
- 🧼 Clean: Carefully wipe the top of the screen and speaker grid with a microfiber dipped in a special screen tool.
- 🛡️ Glass check: Remove the security glass and check the sensor without it. If the problem disappears, replace the accessory with a model with a cutout under the sensor.
- 📱 Covers: Some thick cases with high sidebars can physically interfere with the phone’s lifting to the ear at the desired distance.
- 🌡️ Temperature: In rare cases, condensation inside the speaker grid (after frost or bath) can temporarily disrupt the sensor.
⚠️ Attention: Using cheap protective glasses with full front panel sticking is the most common cause of sensor problems on Redmi Note and Xiaomi Mi series models.
Software calibration of the sensor through the engineering menu
If physical obstacles are eliminated, you need to check whether the sensor itself is working correctly. Xiaomi smartphones have a hidden engineering menu that allows you to diagnose and calibrate the equipment, which is the most effective way to know whether the system sees your face.
To enter the testing menu, open the Phone app and enter the universal code ##6484##. If the code does not work, go to Settings → About Phone → MIUI version and quickly click 7-10 times on the build number until the inscription “You became a developer” appears. Then, in the advanced settings menu, find “Special features” or “CIT”.
☑️ Sensor diagnostics
In the test list, look for the Proximity Sensor. Click on it. You'll see the graph and the numerical values. When you close the top of the screen with your palm (to simulate a conversation), the value should change dramatically (usually from 5.0 to 0.0, and the graph turns green). If the values do not change or change randomly, the sensor is faulty or requires calibration.
To do the calibration, press the Calibrate button at the bottom of the screen. Follow the instructions on the display: usually remove your hand, then close the sensor and remove it again. Once you have successfully calibrated, the system will retain the new sensitivity settings. Reboot the device and check the result in a real conversation.
System settings and additional functions
Newer versions of MIUI and HyperOS have added additional features that may conflict with standard screen locking, such as Pocket Mode or gesture control sometimes override the proximity sensor, and it’s also worth checking the settings of the Phone app itself.
Go to the call settings. To do that, open Phone, click three dots in the corner and select Settings. Find Incoming Calls. There may be an option called Approximation Sensor that needs to be active. In some regions, this setting is hidden, and then only global changes help.
| Parameter | Recommended value | Where to find out. | Impact on the problem |
|---|---|---|---|
| Approximation sensor | Included. | Phone. → Settings → Incoming | Direct lock control |
| Pocket mode | Off (for test) | Settings → Lock screen | Can block the sensor permanently |
| Brightness of the car | Included. | Settings → Screen | Connected to the light sensor |
| Hypersensitivity | Off. | Settings → Screen | Increases false positives |
Also, look at the "High Sensitivity" feature in the screen settings. It's designed to use the phone with gloves, but often causes the screen to respond to cheek touches even when dimming. Try turning this option off if it's active.
Third-party applications and software conflicts
Sometimes the problem is not system settings, but third-party applications that you installed yourself, which can be callers from the Play Market, applications for recording conversations, number detectors, or even some launchers, which can request access to the proximity sensor and process it incorrectly.
To identify the culprit, try running your smartphone in Safe Mode, which only downloads system applications, if the sensor is working correctly in Safe Mode, then the problem is in one of the apps you installed, and delete the recently installed programs one by one, checking the result.
⚠️ Note: Number detector applications (such as GetContact or NumBuster) often have access to the lock screen and can interfere with the normal operation of the Xiaomi sensor.
Also, check the permissions for the Phone app. Go to Settings → Apps → All apps → Phone → Permissions. Make sure the app has all the necessary rights, but there are no redundant permissions for third-party utilities. Resetting the Phone app to factory settings can also help.
Hardware malfunctions and repairs
If software methods, calibration and removal of the protective glass did not help, there is a high probability of hardware failure. The proximity sensor is a physical component that can fail due to impact, moisture or production defect, in which case the screen will never go out, or, conversely, will burn with a black screen constantly.
In some Xiaomi models (e.g. Redmi Note 4, 5, 6 Pro), the proximity sensor plume is a separate module or soldered into the front camera plume, which is a low-cost procedure that requires disassembly of the device. In more modern models, the sensor can be integrated into the screen or board, which makes repairs more difficult.
How to check the sensor without an engineering menu?
Another sign of a hardware problem is that the top of the smartphone is constantly heating up during a conversation, which may indicate a short circuit in the sensor circuit, in which case the use of the phone may not be safe for the battery, and the device is better off before visiting the service.
Frequently Asked Questions (FAQ)
Why does the screen go out but not unlock when I remove the phone from my ear?
Can the MIUI update fix the sensor problem?
Does broken glass affect the approach sensor?
What if the calibration is not saved in the engineering menu?
Is there an app that forcibly extinguishes the screen when you call?
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If neither calibration, nor cleaning, nor resetting the settings helped - the problem is hardware in nature, and you will need to replace the sensor module or plume in the service center.