Many Xiaomi smartphone owners face the uncomfortable situation of a phone call when the screen suddenly goes out.This often happens when you bring the device to your ear and the proximity sensor is activated to save energy and prevent accidental cheekstrokes. However, sometimes the screen stops responding even after you have removed the phone from your face, or locks at the wrong moment, preventing you from using the speakerphone or transferring a call.
The proximity sensor issue on Xiaomi devices is one of the most common user complaints in recent years: This can be caused by both a software glitch in the MIUI or HyperOS shell, and physical obstacles such as a safety glass or case. It is important to understand that turning off this feature will completely deprive you of automatically turning off the screen near the ear, which will lead to accidental taps, so it is better to adjust the sensitivity or eliminate the cause of false positives.
In this article, we will take a closer look at all the possible reasons why a phone gets locked when talking, and provide step-by-step instructions for calibrating, cleaning the cache, and changing system settings. You will learn to distinguish between software glitches and hardware problems, and what hidden developer features can help with the task.
Reasons for Automatic Screen Locking During a Call
The main reason for the fading screen is because of the normal operation of the infrared sensor located at the top of the smartphone body, whose task is to determine the distance to the object. When you hold the phone to the ear, the sensor detects the proximity of the object and signals the system to turn off the display, and if this process occurs too early or the screen does not light up again, then the sensor-system-screen circuit has failed.
Often the problem lies in the wrong calibration after the display is replaced or the device falls. The system may "think" that the object is close to the screen, even when the phone is on the table. Also, the sensor is affected by poor quality protective films that block the infrared radiation, or banal dirt in the area of the conversational speaker.
⚠️ Warning: Do not try to seal the sensor area with tape to prevent blockage.This will cause the screen to burn all the time of the conversation, and you will constantly press the reset or standby button with your cheek.
Another factor could be third-party calling apps that conflict with Xiaomi’s system interface, such as using Viber, WhatsApp, or third-party “calls” from the Play Market sometimes cause errors in the sensor’s signal processing, in which case the standard behavior of the system is disrupted and the screen behaves unpredictably.
Checking the physical condition of the sensor and accessories
Before you go into deep system settings, you need to rule out the banal physical reasons. On Xiaomi models with In-Display screens, the sensor is often hidden under glass, but on budget models with a high-end sensor. IPS-It can be displayed as a small window next to the speaker, and any pollution in that area will be perceived as an obstacle.
Carefully wipe the top of the screen with a soft microfiber cloth. Pay attention to the protective glass or film. If they are curved, have air bubbles or cracks above the sensor area, this can be the cause of the problem. Owners of cases with high sides may also experience the edge of the cover overriding the sensor.
- 🧼 Remove the protective glass and check the sensor without it – this is the fastest way to diagnose.
- 📱 Make sure the case does not cover the top edge of the smartphone, where the sensors are located.
- 🔍 Inspect the area of the speaker for dust and pile, gently clean with a soft brush.
If the problem persists after all the accessories are removed, it means that it is the software or hardware malfunction of the module itself, in which case we move to software calibration.
Calibration of the proximity sensor through the engineering menu
The most effective way to solve this problem is to recalibrate, and the MIUI and HyperOS shells have built-in engineering menus that are accessible through the dialing code, which allows the system to re-remember the distance values for the near and far states.
To start, open the Phone app and enter the combination ##6484##. If the code didn't work, try ##4636## or go to the Service and Feedback menu» → «Verification SIM-maps and nets» → «Testing. On the menu that opens. CIT Find the Proximity Sensor.
☑️ Calibration checklist
Inside the test, you'll see two values: distance in centimeters and status (Near/Far). Close the sensor with your hand (the screen should go out or change status to Near), then remove your hand. The value should change. If there are no reactions or values jump, press the Calibration button at the bottom of the screen. After successful completion, the message "Pass" will appear.
⚠️ Warning: During calibration, keep your phone upright and avoid direct sunlight from hitting the sensor, as the sun’s infrared radiation can knock down the sensor readings.
After successful calibration, be sure to restart the device. A normal screen switch is not enough, it requires a full restart cycle of the reboot system to keep the new parameters in permanent memory.
Sensitivity setting and disabling function in MIUI
Some Xiaomi firmware versions have manual sensor sensitivity adjustments that make the response less acute so that the screen doesn't go out with a slight hand swing next to the device, and you can find this option in the settings section, but it's often changed by developers.
Try to go along the way: Settings → Screen Lock → Mode in your pocket. Make sure this feature is turned off, as it often conflicts with the proximity sensor when calling. Also check Settings → Advanced Settings → Approximation Sensor (if available in your version of MIUI).
If standard methods fail to disable the lock, you can take advantage of the hidden opportunities for developers, but this requires caution. USB Sometimes allows you to reset the configuration of sensors through ADB-commands, but for the average user it is safer to use third-party utilities.
- 📲 Use the “Proximity Sensor Reset” app from Google Play to reset sensor settings.
- ⚙️ Turn off “Mode in your pocket” in the screen lock settings to exclude false positives.
- 🔄 Reset all app settings through the recovery menu if the problem has occurred after the update.
It is worth noting that completely disabling the sensor software without root rights on new versions of Android is almost impossible, since it is a system security feature, so the main task is to ensure that the sensor works correctly, not completely ignore the sensor.
Using applications to control the sensor
If Xiaomi's built-in tools don't work, specialized fixing apps come to the rescue, running on top of the system and forcefully changing the trigger thresholds or emulating the sensor's performance. One of the most popular solutions is the Proximity Sensor Fix app.
Once you install an app, you'll need to give it special permissions, usually through the Accessibility menu, and it'll hang in the background and adjust the data coming from the sensor before it's transmitted to the screen control system.
| Annex | Type of access | Efficiency | Impact on the battery |
|---|---|---|---|
| Proximity Sensor Fix | Special opportunities | Tall. | Minimum |
| Sensor Box | Diagnostics | Medium (test) | Absent. |
| Phone Screen On Off | Device administrator | Medium | Average. |
Add them to the battery exception list so the system doesn’t “kill” the calibration process in the background. To do this, go to Settings → Battery and Performance → Find the app → Select “No Limits”.
Diagnostics of hardware faults
If neither calibration nor applications help, there is a high probability of hardware failure, and the proximity sensor is a physical component that can fail when impacted, moisture is injected, or just from time to time, and in such cases, software fixing is not possible, it requires a replacement part.
Symptoms of hardware malfunction are usually pronounced: the screen either never goes out at all, or goes out immediately at the beginning of the call and does not turn on until it is completed, even if the phone is lying on the table.
For the final check, you can run a deep diagnostic through the CIT menu (code ##6484##). Take the Green Color Test and Proximity Sensor Test. If the last test does not change the values when you close the top edge of the screen, the sensor is physically defective.
⚠️ Warning: Replacing the proximity sensor on modern Xiaomi smartphones is extremely difficult, as it is often soldered into the display plume or integrated into the board.
In some cases, warm-up or a slight tap on the top edge helps (the method is temporary and risky), but this is only a sign that the contact is going away and the device will soon need repair.
Resetting and extreme measures
When all methods are exhausted, the radical but effective way is to completely reset the settings, which will eliminate any software conflicts, accumulated cache files and erroneous configurations of system files that may have affected the operation of the sensors.
Before you do this, make sure to back up all important data, photos, and contacts. Reset will remove all information from the internal drive. Go to Settings → About Phone → Reset → Erase all data.
If even after the factory reset and initial setup (without installing third-party applications) the problem persists, this is an unequivocal diagnosis of hardware failure, in which case no tambourine dancing around the settings will help, and the only way out is a visit to the service.
Remember that ignoring the problem can cause inconvenience in critical moments, such as not being able to quickly put the phone down or turn on speakerphone, so it is better to spend time diagnosing as soon as you notice the strange behavior of the screen.