Faced with Xiaomi suddenly turning off the display while listening to WhatsApp audio messages, many users are puzzled: this behavior is often perceived as a system failure or an application error, but in most cases it is a normal operation of the proximity sensor. The smartphone mistakenly “thinks” that you held it to your ear, and saves energy by turning off the backlight.
The problem is relevant for owners of devices based on the MIUI shell and HyperOS, where sensor control algorithms are configured to aggressively save energy. In this article, we will analyze the mechanics of the process, check the settings and propose specific solutions to correct the situation so that voice messages are played correctly.
Mechanics of the approximation sensor in MIUI
The main reason why the screen goes out is the proximity sensor, which is located at the top of the body (often hidden under the screen or next to the speaker), responds to changes in light and infrared reflection, and its task is to turn off the display during a phone conversation when the phone is near the ear to prevent accidental cheek pressing.
But in WhatsApp, the logic can get lost. When you launch a voice message, the app sends a sound signal to the system. If the user's hand or protective film is blocking the sensor area at that point, the system interprets this as the beginning of the conversation and turns off the screen. On models with an in-display sensor, the probability of false positives is higher due to software calibration algorithms.
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Frequently rubbing the top of the screen with an alcohol napkin can remove the oleophobic coating, but sometimes temporarily solves the problem of static electricity interfering with the sensor.
It's important to understand that MIUI prioritizes the call function over multimedia, so even if you listen to "voise," the system can force the ear mode to activate, which is especially true for older firmware versions where the sensor optimization was not done correctly.
WhatsApp app settings and sound playback
The second aspect of the problem is the settings of the messenger itself: WhatsApp has a separation between playback through the speaker and through the speaker speaker, and if the default is to output audio through the speaker (small, top), the system automatically activates the proximity sensor, waiting for you to hold the phone to your ear.
To change this behavior, you need to go to the settings inside the chat. When you play the message, look at the speaker icon. If it's a phone near the ear, then the mode is activated. Switching to a regular speaker (loud communication) often solves the problem, because in this mode the proximity sensor is blocked programmatically.
Also, check the app's permissions. Sometimes the conflict arises because WhatsApp is not allowed to control the sensors in the background or when the screen is locked. Go to Settings → Apps → WhatsApp → Permissions and make sure that all the necessary items, especially those related to the microphone and phone, are activated.
Effects of protective glasses and covers on sensors
Physical factors are as important as software. Cheap security windows or improperly pasted film can block the sensor's range, and even a microscopic gap or air bubble at the top of the screen can distort the sensor's readings, making it think something is pressed against the phone.
High-sided cases can also be the reason. If the side of the side closes the top edge, when you grab the smartphone with your palm, your finger can touch the sensor area. At which point the screen goes out. Check if the accessory covers the top of the display, and try to remove the case for diagnosis.
⚠️ Attention: The use of thick black-framed protective glasses on smartphones with a subscreen proximity sensor (Redmi Note, Mi series) in 90% of cases leads to constant false positives and a fading screen.
The sensor is also affected by the cleanliness of the surface, and the fatty spots, water droplets, or dust in the area of the speaker can scatter the IR radiation of the sensor, causing it to actuate. Regularly wiping the top of the screen with dry soft cloth is a simple but effective preventive action.
Program conflicts and the “In the pocket” mode
The MIUI shell has a Pocket Mode feature that blocks random taps when the phone is in the bag. This feature uses the same proximity sensor. If it's not working properly or is too sensitive, the screen can go out even without putting the phone in your pocket, just by putting your palm over the top while using WhatsApp.
To disable this feature, go down the path: Settings → Lock screen → Pocket mode. Disabling this option often solves the problem of spontaneous screen suppression in various applications, not only in messengers. However, remember that without this feature, the risk of random dialing in your pocket increases.
☑️ Sensor diagnostics
Another reason could be third-party memory cleanup apps or “accelerators” that aggressively control background processes. They can force the screen to go out, believing that the user is not interacting with the interface directly while the audio is playing.
Engineering menu and sensor calibration
If the software settings didn’t help, the sensor may need calibration. Xiaomi smartphones have a hidden engineering menu that allows you to test and configure hardware components, and access it using a special code entered in the Phone app.
Type ##6484## (or ##4636## on some models). In the CIT menu that opens, look for the Proximity sensor. Here you can see the current sensor readings. Close the top of the screen with your hand, the value should change from 5.0 (or 1.0) to 0.0. If the values do not change or jump randomly, the sensor may malfunction physically.
The command to enter the CIT (engineering menu):
##6484##What if the sensor is constantly showing 0 in CIT?
The Calibrate button is often available on the same menu, and when you press it, follow the instructions on the screen (usually ask you to close and open the sensor). After you successfully calibrate, reset the device, which resets the software thresholds of sensor sensitivity.
Comparison of models and frequency of problem
The problem with the fading screen when voice messages is distributed unevenly among the different models of Xiaomi, Redmi and POCO. This is due to the type of sensor used (separate module vs. subscreen) and the version of Android.
| Series of devices | Type of sensor | Probability of problem | The main reason |
|---|---|---|---|
| Redmi Note 8/9/10 | Underscreen | Tall. | MIUI software bug |
| Xiaomi Mi 9/10/11 | Laser/Separate | Medium | Protective glass |
| POCO X3/NFC | Built into the button | Low. | Physical overlap |
| Redmi 9A/9C | Separate module | Medium | Low sensitivity |
As you can see from the table, owners of devices with subscreen sensors face the problem more often, because it is more difficult for software to filter interference from touching with your fingers across the entire screen area than it is to read from a separate physical sensor.
Radical Solutions and Resetting
If nothing works, you can either reset or flash it. Sometimes the system accumulates errors in the configuration files of the equipment (persist partition) that are not fixed by a normal reboot. Reset to factory settings (Settings → About Phone → Reset) can clear this data.
Before performing a full reset, make sure to back up your data to Google Account or Mi Cloud. After reset, do not restore all applications from the backup at once - check WhatsApp's work on a "clean" system. If the problem disappears, then the conflict caused a third-party application or cache.
⚠️ Note: Do not try to reflash the phone with custom recaveri (TWRP) And sensor patches, if you're not an experienced user, can cause the sensor to be completely inoperable and the warranty to be lost.
In extreme cases, if the sensor is physically defective (broken, flooded), software methods will not help, in such cases, only replacing the module in the service center or using software crutches that turn off the sensor completely (which is inconvenient for calls).