Why Xiaomi’s screen goes out when you call and how to fix it

The way Xiaomi's screen goes out during a phone call is familiar to many smartphone owners, who hold the phone to their ears, the display turns off to save power and prevent accidental taps, but after the conversation is over or the device is removed, the screen doesn't light up, which creates serious inconveniences because it becomes impossible to complete a call, turn on speakerphone or dial a number through the keyboard, and most often the problem lies in the incorrect operation of the proximity sensor, which is responsible for this function.

In most cases, you shouldn't panic, because it's a software failure or contamination, not a hardware failure. The MIUI system that Xiaomi, Redmi and POCO phones are based on has its own sensor calibration features. Sometimes, after updating the firmware or sticking the security glass, the settings get lost. Understanding how this module works will help you quickly return functionality to the device without going to the service center.

In this article, we will look at all the possible reasons why the display turns off at the wrong time, and provide step-by-step instructions for restoring normal operation. We will look at both standard methods of setting up through the engineering menu, and deeper ways to solve the problem, including resetting parameters.

The principle of the sensor approach in smartphones Xiaomi

The screen responds to the phone's face in a special module called the proximity sensor. In Xiaomi smartphones, it's usually located at the top of the front panel, often hidden under glass next to the speaker. This sensor emits infrared light and analyzes its reflection from objects. When you hold the phone to your head, the light reflects, and the system receives a signal that the object is close.

Once the signal is received, the Android operating system, in conjunction with the MIUI shell, initiates a switch off of the display matrix, which is necessary for two purposes: saving battery power and locking the touchscreen so that the cheek does not press the reset or switch to speaker communication button. If the calibration is broken, the sensor can “think” that the object is nearby even when the phone is on the table, or vice versa, not see obstacles.

There are two main types of sensors used in different models:

• 📡 Hardware sensors are physical modules that can become contaminated or unstuck.
• 💻 Virtual sensors – software algorithms that analyze data from the front camera and accelerometer (often found in modern models with a cutout in the screen).

Understanding your sensor type is important because the methods of diagnosing it may differ, and virtual sensors are more likely to be affected by software bugs after system updates.

⚠️ Warning: If you have recently changed the display or body of your phone, make sure the wizard correctly installed the sensor plume. Unconnected connector is a common reason that the screen stops responding to the approach.

The main reasons for the failure of the screen during the call

Before we get to the complex settings, we need to rule out the trivial physical factors, and most often, the problem is that something is blocking the sensor's view, and even a thin layer of fat from the fingers, a dust in the speaker's grid, or a shifted protective film can distort the readings, and the system perceives this as being in a constant position of an object next to the phone.

The second most popular cause is software conflicts: After updating MIUI or installing third-party applications to manage calls (such as Google Play "calls"), interrupt handling errors can occur, and smart sleep/wake cases that can magnetize the device's sensors also affect the device.

The main reasons also include:

• 🛑 Incorrect calibration – downgraded threshold values of feelings

Identity.

Malware

Overheating or hypothermia

If the phone fell or was hit, the sensor module itself could be damaged, which would require hardware replacement rather than software.

Basic inspection and cleaning of the top of the smartphone

The first step is to do a thorough visual inspection and clean the top of the device, so take a soft microfiber and wipe the area around the speaker, and often users don't notice that the security glass is offset and overlays the sensor, so the screen goes out immediately after the call starts and doesn't turn on.

Check to see if you have apps that can intercept call management. Some call enhancers or themes have their own screen control settings. Try temporarily disabling Bluetooth headsets or smartwatches if they are paired with a phone to rule out their impact on the logic of the system.

If after cleaning and restarting the problem persists, proceed to software calibration.

Engineering menu: calibration of the proximity sensor

The most effective way to solve the problem is to calibrate through the CIT (Customer Integration Test) menu, which is a hidden part of the system designed to test components. To enter it, open the Phone app and type in the combination ##6484##. If the code does not work, try ##4636# or go through the settings menu.

In the test list that opens, look for the Proximity sensor. You click on it and you'll see the readings that are current. Close the top of the phone with your hand, and the values should change (usually from 5.0 to 0.0 or vice versa, depending on the model). If you don't respond, press Calibration or Start and follow the instructions on the screen: close and open the sensor on command of the system.

Table of the sensor state values in different modes:

After successful calibration, be sure to press Pass or Save to save the new settings to the device's memory.Without this step, the settings will reset after the reboot.

System settings and additional applications

If calibration doesn't work, check system settings that can force the screen to lock. Some versions of the MIUI shell have a Pocket Mode or Pocket Mode feature, which is designed to prevent accidental taps, but often works incorrectly, and you can turn it off from the Settings menu -> Lock Screen or through a search for settings.

Also worth looking at are memory cleaner and antivirus apps. They may have their own screen control permissions. Go to Settings -> Apps -> All apps, find suspicious software and check its permissions. If you use a third-party caller, try temporarily returning a standard app from Google or Xiaomi.

Useful actions in settings:

• 🔍 Reset application settings – returns all access rights to the original values.
• 📵 Disabling gestures – sometimes the gestures affect the sensors.
• 🔄 Update components – check Services and Feedback for updates to system modules.

Often, simply resetting the settings to factory settings (with data saved) solves the problem if it is caused by a deep software conflict.

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Before you complete a Hard Reset, make sure to back up all important data to the Mi Cloud or your computer, as the process will remove all information from your internal memory.

Specific problems of Redmi and POCO models

Owners of the Redmi and POCO budget lines often encounter the design feature where the proximity sensor is located under the display or combined with the speaker. In such models (for example, the Redmi Note series), factory calibration may not be perfect. There is a separate method of resetting through the engineering menu described above, but sometimes a more radical approach is required.

Some models have a problem with sticking the sensor in the software, and this helps to clear the cache of the Phone and System Interface system process. Go to Settings -> Applications -> All applications, find those processes, select Memory and click Clear. This will not delete your contacts, but will reset temporary files that may have caused the error.

⚠️ Warning: Do not use "people's" applications to calibrate sensors from unverified sources, they may request excessive access rights and disrupt the stability of the security system. MIUI.

If you have a model with a cutout (“bangs”) or a hole in the screen, make sure that the display settings do not turn on the cutout hide mode if it affects the sensor area. In rare cases, changing the screen resolution or interface scale helps, which restarts the graphics driver.

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For models with a virtual proximity sensor, it is critical to keep the front camera area clean, as it is used to determine the proximity of objects.

When hardware repairs are required

If none of the software methods worked, and the sensor shows persistent errors or no response in the engineering menu, it's probably a physical problem, it could be a detached plume, an oxidized contact after moisture hits, or the module itself fails, and in such cases, the software calibration is useless.

Signs of hardware malfunction:

• 🔨 Mechanical damage – the phone fell or was crushed.
• 💧 Moisture infestation – even drops of sweat or rain can cause contacts to corrosion.
• 📉 Gradual degradation – the sensor worked worse every month until it stopped working.

In this situation, you need to contact an authorized service center for the diagnosis and replacement of the component. Self-disassembly of modern Xiaomi smartphones is difficult due to adhesive joints and can damage other nodes.

Sometimes, a temporary solution like turning off the proximity sensor through special commands or root rights helps, but it will deprive you of the automatic screen-off function, which is inconvenient, so replacing the sensor is the most rational solution to restore full functionality of the device.

Frequently Asked Questions (FAQ)