The situation when the screen goes out at the most inappropriate moment of conversation is familiar to many owners of Xiaomi smartphones. Instead of seeing the call interface or completing the call, the user is faced with a black, unresponsive display. It is not just an annoying bug, but a consequence of the operation of the system of protection against accidental pressing, which in this case functions improperly. Often the problem lies in the banal contamination or improperly pasted security glass, but sometimes requires deeper intervention in the settings of the system.
Modern Xiaomi smartphones are equipped with sensitive sensors designed to improve the user experience. However, when MIUI or HyperOS software misinterprets sensor data, it leads to premature backlighting. In this guide, we will detail the mechanics of the proximity sensor, look at software failures and suggest step-by-step methods for troubleshooting your calls to pass comfortably.
It's important to understand that ignoring this problem can cause important calls to reset or randomly activate features like turning off the microphone or turning into a hold mode. So if you notice that the display stopped burning during a conversation, don't delay diagnosis. We'll go from simple physical checks to complex system settings to get your device back running smoothly.
Mechanism of the sensor of approach on Android
The main culprit behind the dimness of the screen when you hold the phone to your ear is the proximity sensor, which is a small module that is usually located at the top of the front panel that uses infrared radiation to determine the distance to the object. When you bring the phone to your face, the sensor picks up the reflected signal and tells the system to turn off the display to prevent accidental tapping of the cheek or ear.
Xiaomi and Redmi use different types of sensors: virtual (front camera-based) and physical (separate module) physical sensors are often hidden under the display bezels or in the speaker's notch, making them vulnerable to contamination. If the system receives a false signal that an object is close, it forcibly extinguishes the screen, even if the phone is 10-15 centimeters from the face.
The correct operation of this mechanism is critical for energy efficiency and convenience. However, the sensor calibration can be lost after updating the firmware or mechanical impact. In such cases, the trigger threshold becomes too high, and the screen reacts to the slightest movement of the hand or tilt of the head, creating the illusion of permanent malfunction.
⚠️ Note: If you have recently changed the display or the case of a smartphone in a third-party service, the problem may lie in the absence of a calibration sticker above the sensor or improper assembly of the module.
Physical causes: protective glass and pollution
The most common reason that the screen goes out for no apparent reason is because of the wrong security glass. Many universal glasses have a black frame or a solid coating at the top that covers the area of operation of the sensor. Even the minimal displacement of such glass when the sticker is placed can lead to the sensor constantly "seeing" the obstacle.
Also, the mud, greasy spots, or dust in the area of the speaker can distort the readings of the infrared emitter. The sensor perceives the layer of dirt as an approximate object and activates the energy saving mode by turning off the backlight. Regular cleaning of the top of the smartphone with soft microfiber fabric often solves the problem instantly.
Also worth noting is the cases. Some models of case protection have protruding sides or a cover that can partially overlap the top of the device. If the case is deformed or too thick, it creates a permanent shadow in the area of the sensor, which the system perceives as a signal to turn off the screen.
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Use protective glass with a sensor cutout or transparent coating at the top ("Full Glue" without black bezels) to avoid sensor sensitivity issues.
To test for the effects of accessories, do a simple test: remove the case and wipe the screen, then make a test call. If the problem disappears, it was external factors that caused the problem. If the screen continues to go out, you need to move to software settings.
Checking and calibrating the sensor through the engineering menu
If physical causes are excluded, the next step is to diagnose through the hidden MIUI engineering menu, which allows you to check the current state of the sensor and recalibrate it, accessed through the standard Phone application by entering a special code.
Type ##6484## or ##3646633## in the dial box. The CIT menu will open. In the test list, look for the "Proximity Sensor" or "Proximation Sensor." When you click on it, you'll see the current readings. Close the top of the screen with your hand and remove it: values should vary from 0.0 to 5.0 (or similar units).
☑️ Diagnostics of the proximity sensor
If the values do not change or change in a jump, press the Calibrate button. Follow the instructions on the screen: you usually need to close and open the sensor several times. After successful calibration, be sure to restart the device so that the new parameters apply to the system.
⚠️ Warning: Do not change other settings in the engineering menu unless you are sure of their purpose.Incorrect change of the display or network settings can lead to unstable operation of the smartphone.
MIUI settings and system limitations
There are additional features in the MIUI shell and the new HyperOS that can conflict with the sensor’s performance, such as In Your Pocket mode, which is designed to block random taps when the phone is in your bag, but sometimes it works falsely, and disabling this feature can solve the fading screen problem.
To access settings, go to Settings → Lock and Protect → Mode in your pocket and turn off the switch. It’s also worth checking the settings for special features. Settings Path → Advanced Settings → Special Features → Approximation Sensor (if available in your version of the OS) allows you to control sensitivity or disable the sensor software, although this option is often hidden in new versions of Android.
Another important aspect is energy saving: Aggressive energy saving algorithms can prematurely turn off the backlight if the phone is not in use. Try switching the power mode from "Economies" to "Balanced" or "Production" and check the result.
Third-party applications and software conflicts
Installed applications for managing calls, recording conversations or smart shells can intercept the proximity sensor. If a problem occurs after installing new software, try removing it or running the phone in safe mode. In safe mode, only system applications are loaded, which allows you to exclude the influence of third-party software.
To enter Safe Mode, press the power button, and then hold your finger on the Turn Off button on the screen for a long time until you are prompted to go to Safe Mode. If in this mode the screen stopped going out spontaneously, then one of the installed applications is to blame. Remove them in turn to find culprit.
Special attention should be paid to “cleaner” applications and memory optimizers, which often have their own screen and sensor controls that may conflict with Xiaomi’s system settings, and removing such programs often returns stability to the device.
| Type of problem | Probable cause | Method of decision | Difficulty |
|---|---|---|---|
| The screen goes out immediately. | Sensor contamination | Wipe the top of the screen. | Low. |
| Black glass in a case | Accessory design | Replace the glass/case | Low. |
| It works in your pocket. | Protection regime | Turn off in the settings | Low. |
| Calibration doesn't help. | Hardware failure | Replacement of the plume/module | Tall. |
Hardware malfunctions and repairs
If software and cleaning methods fail, there's a high probability of hardware failure, and the proximity sensor may fail due to moisture, a fall, or a manufacturing defect, and in such cases, the screen will go out chaotically or not turn on at all, even when the phone is lying on the table.
A common problem is the drift of the plume connecting the sensor to the motherboard, which can happen after a major impact, repairs require disassembling the device and reconnecting or replacing the plume, and you can only do this yourself if you have the experience and tools, because you risk damaging other components.
Can I temporarily shut down the sensor?
In some Redmi and Poco models, the proximity sensor is combined with a front-facing camera or speaker in a single module. Replacing one element may require replacing the entire node. If the device is warranted, it is strongly recommended to contact an authorized service center for free repairs.
⚠️ Warning: Attempting to replace the sensor on waterproof devices will violate the tightness of the case, which may lead to a denial of warranty service in the future.
FAQ: Frequently Asked Questions
Why does the screen go out when I just hold my phone in my hand?
Can the proximity sensor be completely turned off?
Does the Android update affect the sensor?
Will resetting to factory settings help?
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In 80% of cases, the problem is solved by replacing the protective glass or simply calibrating through the engineering menu, without requiring expensive repairs.