Dims the screen when calling on Xiaomi: a complete guide to elimination

The situation when the screen of Xiaomi smartphone goes out at the most inappropriate moment of conversation is familiar to many owners. You hold the phone to your ear, the display dims — this is the normal operation of the proximity sensor, but sometimes the screen does not light up when you remove the device, or goes out while lying on the table. This is annoying, because you can not press the speaker button or dial a number through DTMF.

The reasons for this behavior can be found in software failures of the MIUI or HyperOS operating system, as well as in physical dirt on the sensors, often the culprits are protective glasses that block the sensors, or incorrect energy saving settings that aggressively turn off the display to save charge.

In this article, we'll look at all the possible solutions to this problem, and we'll look at sensor calibration, system function settings, and how to check for hardware health, and you don't have to be an engineer to do most of these things yourself.

How the proximity sensor works and why it is important

The main element that's responsible for quenching the screen is the proximity sensor, which is usually located at the top of the front of the smartphone, next to the speaker, and it's designed to respond to the change in reflected infrared radiation, and when you bring the phone to your head, the sensor picks up the object and sends a signal to the system to turn off the display.

This is necessary for two purposes: preventing accidental cheekstrokes during a conversation and saving battery power. If the screen goes out too early or does not turn back on, then the calibration is knocked down or the module itself is contaminated. Modern Xiaomi models often use a virtual sensor that is tied to the front camera and software algorithms.

⚠️ Attention: Using tight black-framed protective glasses or glasses that don't have a sensor cutout is the most common cause of malfunction. They can physically override the sensor, causing the phone to "think" it's in the ear all the time.

The sensor problems can manifest themselves in many ways: sometimes the screen goes out as soon as the call starts, even if the phone is on the table; other times, it refuses to light up until you press the power button; understanding how it works helps to diagnose the source of the malfunction more quickly.

Checking and cleaning of the upper part of the body

Before you go into deep settings, you have to rule out the trivial physical causes: the top of your smartphone is where dust, skin fat and pile are piling up from your pockets, and even the thinnest film of dirt can scatter the sensor's IR radiation, causing false positives.

Carefully wipe the area around the speaker and the front camera. Use soft microfiber fabric lightly moistened with alcohol solution. Do not use aggressive chemistry that can damage the oleophobic coating. Pay special attention to the speaker grid - there often gets stuck dust.

• 🧼 Wipe the screen and upper frame with a microfiber with alcohol.
• 🛡️ Remove the protective glass if it closes the sensors.
• 🧹 Carefully clean the speaker mesh with a soft brush.
• 📱 Check if the glass is not curved with displacement.

If you use a high-sided case, make sure it doesn't press on the top edge of the screen. Some security accessories can create a micro-gap between the glass and the sensor, which causes the data to be misread, and in such cases, the replacement of the accessory helps.

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Try making a call without the safety glass, and if the problem is gone, it means that the glass is to blame, and it is better to replace it with a model with a cutout for the sensor or a thin film.

Setting up the proximity sensor through the engineering menu

Xiaomi and Redmi have a hidden engineering menu for testing and calibrating hardware components, the most efficient way to check if the sensor module itself is working, and the menu is logged in with a special code that works on most versions of MIUI.

Open the Phone app and enter the combination ##6484##. If the code didn't work, try ##4636##. In the menu that opens, select "Proximity sensor" or "Approximation Sensor." Here you will see the current value. If you hold your hand to the top, the value should change from 5.0 to 0.0 (or vice versa, depending on the version).

1 Enter ##6484## in the dialer


2.Find Proximity Sensor




3. Press Calibrate (Calibrate)




4. Remove your hand from the sensor and press OK

If the values don't change or change randomly, there may be a hardware problem, but in 90 percent of cases, simple calibration helps. Press Calibration, remove your hand from the screen, wait until the process is complete, and press OK. After that, restart the device.

Disconnecting the “In the pocket” mode and energy saving

One feature that often conflicts with the proximity sensor is In Your Pocket mode, which is designed to lock the screen when the phone is in your bag or pocket to avoid random calls.However, algorithms can make mistakes and turn off the screen during a conversation if the phone is lying on a soft surface.

To turn off this feature, go to Settings → Lock and Protection → Mode in your pocket and turn off the switch. This action often solves the problem when the screen goes out while lying on the couch or table. It is also worth checking the energy saving settings for the Phone application.

The system can aggressively restrict the background of the call, leading to incorrect sensor surveys. Go to Settings → Applications → All applications → Phone. Select "Battery Saving" and set "No Limits" to give the system priority to work with the sensors during the call.

⚠️ Warning: Turning off In Your Pocket mode can lead to accidental taps if you carry your phone in a narrow pocket without a case.Be careful when choosing this option.

Resetting the settings of the “Phone” application and cache

Sometimes the problem is not the hardware, but the software failure of the application itself, which is responsible for the calls, the accumulated cache or conflicting data can distort the processing of signals from the sensors, in which case the cleaning of the application data helps.

Go to Settings → Applications → All apps. Find the phone (green handset icon) in the list. Click on “Clean” and select “Clean all.” Don’t worry, your contacts and call history won’t be deleted, as they’re stored in a separate system storage or cloud.

Once the data is cleaned, you need to restart your smartphone. The first call may be delayed because the system needs to re-initiate the processes. If you have third-party software installed for calls (such as Google Dialer or Truecaller), try to delete them and check the regular call.

Comparison of models and frequency of problems

The screen quenching problem is not the same for all models, and some Xiaomi and Redmi series of smartphones are more prone to sensor software errors due to the location of components or the versions of Android used.

As you can see from the table, owners of budget and mid-budget models are most likely to experience this, and this is due to the use of virtual sensors that depend entirely on software processing of the image from the front camera. Any processing delay leads to a lag of screen activation.

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Owners of models with a virtual sensor (Redmi Note series) often help to reconfigure the sensitivity or change the protective glass to a thinner one.

When repair or replacement of parts is required

If the software, calibration and cleaning methods didn't work, there's a hardware malfunction, which could be a drop of the proximity sensor plume from the motherboard, oxidation of the contacts, or failure of the module itself, which often happens after falls or moisture.

In some models, the proximity sensor is integrated into the front camera plume or the bottom plume module (depending on the design), and replacing these components requires disassembly of the device and the availability of tools. Self-repair is possible if you have experience with small electronics.

• 🔧 The plume's departure after the phone fell.
• 💧 Oxidation of contacts due to moisture.
• 📉 Physical failure of the IR emitter.
• 📱 Factory soldering defect on new devices.

To diagnose at home, you can carefully (without fanaticism) press the top of the screen in the speaker area during the call, and if the screen lights up when pressed, then the problem is the contact of the plume, in which case a trip to the service center is inevitable.

⚠️ Warning: Do not try to disassemble the phone if it is under warranty. Self-opening the case will lead to the loss of warranty obligations.

Frequently Asked Questions (FAQ)