The situation when the smartphone screen continues to burn during a conversation is familiar to many owners of Android devices. Especially often this problem is faced by users who choose Xiaomi products. Instead of going out immediately after putting the device to the ear, the display remains active, which leads to accidental cheek pressing, resetting the call or turning on the speaker at the most inopportune moment. This is not just a minor inconvenience, but a serious failure in the operation of the proximity sensor, which requires immediate attention.
Ignoring this malfunction can cause the battery to run out quickly and even overheat, as the backlighting of the display is one of the main consumers of energy. In addition, constant casual touch during a conversation can be annoying and confusing. In this article, we will discuss in detail why the touch screen behaves incorrectly, what software and hardware factors affect the operation of the sensor, and how to return the gadget to normal functionality without going to the service center.
There are many reasons, from the banal protective film to serious errors in the code of the operating system MIUI or HyperOS. Understanding the nature of the problem is the first step to its successful solution. Below we will consider all possible scenarios and provide step-by-step instructions for troubleshooting. In 80% of cases, the problem is solved by software calibration of the sensor, which does not require root rights.
The principle of operation of the proximity sensor and its role in the system
To understand the problem, you have to understand the physics of the process. The top of the smartphone frame, usually next to a speaker, hides an infrared proximity sensor underneath it, and it works by emitting infrared light that is invisible to the human eye and analyzing the reflected signal. When you hold the phone to your ear, the object (head) interrupts or reflects this signal, and the controller tells the operating system to turn off the display.
Xiaomi devices use different types of sensors. Older or budget models often use physical sensors that can get clogged with dust. Modern flagships and mid-range devices are increasingly embracing virtual sensors that use front-facing camera data and machine learning algorithms. A software failure to process this data can cause the system to simply “not see” your ear.
Importantly, this module works closely with calibration files stored in a hidden partition of memory. If this data is damaged as a result of a failed firmware update or a file system failure, the screen will not respond to the approach.
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If you have recently changed the display or glass, the problem may lie in the wrong installation of the plume or the lack of a protective sticker on the sensor inside the case.
Main reasons for call resets and active screen
The first thing to look at when diagnosing is external factors. Often users do not even suspect that the protective film or glass caused the malfunction. If the accessory closes the area of the sensor or has a defect in this area (air bubbles, cracks, greasy spots), the infrared rays will dissipate incorrectly, as a result of which the phone "thinks" that it is still at a distance from the face, and does not extinguish the display.
The second common cause is software conflict: MIUI and HyperOS have complex power optimization and memory management systems; sometimes background processes kill the system service that handles sensor signals; and problems can arise after a system update when new drivers misinteract with the hardware of the device.
The third factor is pollution. The speaker and the sensor area are magnets for dust, pile and earwax. Even a microscopic layer of dirt can block infrared radiation. Smartphone owners without covers often find that the sensor gets clogged when they wear it in their pocket, and in such cases, it requires physical cleaning of the device using special tools rather than software.
- 📱 Protective glass: Incorrectly pasted film or glass with a black frame overriding the sensor.
- 🧹 Pollution: Dust, fat or moisture in the upper speaker and chamber.
- ⚙️ Failure of the software: errors in the work of Android system services or shell manufacturer.
- 🔧 Hardware breakdown: Failure of the sensor module itself or the plume’s departure after falling.
Programmatic calibration of the proximity sensor
The most effective way to solve the problem without disassembling the device is calibration. In Xiaomi smartphones, there is a hidden engineering menu that allows you to test and calibrate all hardware modules. To enter it, you need to open the standard Phone application and type a special command. Dial the code # # #6484## or ##4636#. If the first code does not work, try the second one or find the Service and Feedback menu item Testing (CIT).
When you enter the engineering menu, you will see a list of dozens of tests, and you will need to find a item called the Proximity sensor or Approximation Sensor. You will click on it. You will see two values: current state (usually 0.0 or 5.0) and status. Hold your palm to the top of the screen and remove it. If the numbers change (for example, from 5.0 to 0.0), then the sensor is physically intact and the problem lies in the software calibration.
To fix the situation, press Calibration or Start. The system will ask you to remove your hand from the screen and then close the sensor. After passing the test, press Pass or OK, and then make sure to select Save or Finish. After that, you need to completely restart the device so that the new parameters take effect. This method helps in most cases of software dissynchronization.
☑️ Calibration checklist
Sensitivity settings and system parameters
Sometimes standard calibration is not enough and manual sensitivity adjustments are required. Some versions of MIUI firmware have a separate menu for setting up the sensors. Go to Settings → Advanced Settings (or "Special Opportunities") → Approximation Sensor. There may be a Sensitivity Mode switch or an adjustment slider available. Turning on this mode causes the system to respond to weaker changes in the reflected signal.
Also check lock and screen settings. Go to Settings → Screen and make sure that no modes that may conflict with the sensor are enabled, such as “Mode in your pocket” (if it is not working correctly, try turning it off). Also, in the Lock and Protection section, check if the “Raise to turn on” function is activated, which can sometimes interrupt the proximity sensor signal.
If you have access to a computer and debugging skills, you can try resetting the sensor parameters through ADB-But most of the time, it's easy to clear the data from the system application that controls the sensors. → Annexes → All applications, find in the list "Proximity" or "Proximity" (may need to enable system process display) and click "Clear" → Clear everything.
Secret code to reset sensor
Effects of protective accessories and physical condition
As mentioned, protective glass is a frequent problem, especially for wide black-framed glass, which glass manufacturers make universal. If the black stripe on the glass covers the sensor area, the infrared radiation is blocked. The solution is to carefully remove the protective coating. If the problem disappears after removing the glass, you will have to buy a new, better glass with a cutout for the sensor, or accept the inconvenience.
The physical condition of the body also plays a role. If the phone fell, even from a low height, the microscopic connector of the sensor plume could move away. In models where the sensor is embedded in the display plume, the problem can be solved by reconnecting the plume. However, in modern monolithic designs, this requires skilled disassembly. It is also worth checking whether the battery has swelled. In rare cases, the ballooned battery presses on the internal components, displacing the sensor.
The hygiene of the device is an important aspect. Take a soft toothbrush or cotton swab slightly soaked in isopropyl alcohol (not in water!), and carefully clean the upper speaker area. Don't pour liquid directly onto the phone! Movements should be sweeping. Often, compressed dust accumulates inside the speaker's grid, which blocks the sensor from working for years.
| Type of problem | Symptoms. | Probability of solution | Elimination method |
|---|---|---|---|
| Dirty glass | The screen goes out with a delay | High (90%) | Alcohol cleaning |
| Poor quality film | The screen doesn't go out at all. | Very high (99%) | Film replacement |
| Calibration failure | Unstable work | High (85%) | Engineering menu |
| The plume's breakdown | Total lack of response | Average (50%) | Replacement in the service |
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The quality of the protective glass directly affects the operation of the IR sensor: cheap accessories often have an opaque frame that blocks the sensor.
⚠️ Warning: Do not use aggressive chemical solvents such as acetone or gasoline to clean the sensor, which can damage the oleophobic coating of the screen and melt the plastic frame of the speaker.
Third-party applications and software conflict
The apps you install can interfere with your system, especially memory cleaners, antiviruses and call management apps, which may have permissions to control sensors or lock the screen, which creates a conflict with Xiaomi's system settings. Try running your phone in Safe Mode. To do this, press the turn off button and then (hold on) the "Stop" icon on the screen until you get a suggestion to go to Safe Mode.
If the sensor is working correctly in safe mode, it means that one of the installed applications is to blame. Start remembering what you installed before the problem appeared. Often the culprits are applications for recording calls, automating tasks (like Tasker), or weather widgets that constantly poll the sensors, removing or updating such an application solves the problem.
Also worth checking for system updates. Xiaomi regularly releases bug fixing patches. Go to Settings → About the phone and click on the MIUI/HyperOS version. If an update is available, install it. Sometimes resetting to factory settings helps, but this is an extreme measure that requires all data to be saved beforehand.
- 📉 Analyzers: Battery monitoring apps often block sensors to save energy.
- 📞 Callers: Third-party dialing apps may not handle interrupts properly.
- 🛡️ Antiviruses: Can block access to hardware.
- 🤖 Automation: macro scripts can force the screen on.
⚠️ Warning: Before entering Safe Mode, make sure you know the passwords from your accounts, as some apps may require re-authorization after you quit this mode.
FAQ: Frequently Asked Questions
Why does the screen go out on its own when I don’t hold my phone to my ear?
Can a MIUI update break the proximity sensor?
Will the reset to factory settings help if the sensor is physically fit?
What if the sensor stopped working after the screen was replaced?
Does a magnetic bookcase affect the sensor?
⚠️ Note: If none of the software methods worked, and the calibration in the engineering menu shows constant zeros or maximum values regardless of the position of the hands, a hardware breakdown of the module is likely.