The situation when the screen of Xiaomi smartphone does not go out during a phone conversation, familiar to many users. This is not only annoying, as you constantly touch the cheek of the answer button or hands-free communication, but also creates the risk of accidentally completing the call or turning on the speaker. The problem most often lies in the incorrect operation of the proximity sensor, which is physically located at the top of the device body, it must respond to the approach of the object (your ear) to the display and give the system a command to lock.
In modern MIUI and HyperOS shells, sensor algorithms have become more complex, but sometimes they conflict with protective films or software failures. The most common reason for blocking is not a hardware malfunction, but a software calibration bug or a facial unlock feature that forces the screen to be active. Understanding how the system manages this process will help you quickly troubleshoot the problem without going to the service center.
In this guide, we'll look at all the possible reasons why the display keeps glowing when you hold the phone to your ear. We'll look at sensor settings, facial recognition features, and software calibration. It's important to consistently check each item, because the solution can come from a combination of factors.
Main cause: proximity sensor and face unlock conflict
The most common reason Redmi or Poco screens don’t go out during a call is because of the Android security logic: When you activate the face unlock feature, the smartphone tries to constantly scan your face during an incoming or outgoing call to quickly unlock the device or show notifications if necessary. This makes the lighting and proximity sensors work in priority mode, often ignoring the signal from the proximity sensor.
Android is designed to prioritize security (unlock) override the standard behavior of the caller interface. If the proximity sensor gives even the slightest error or delay, Face ID wins and keeps the display on, especially in models with a cut-out droplet or leaky screen, where the sensors are located in close proximity to the front camera.
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Try temporarily turning off the face unlock and check the call, and if the screen starts to go out, the problem is the software conflict, not the sensor breakdown.
To check if this is your problem, you need to log into your security settings. Open Settings, then go to Password and Security. Find Face Unlock or Face ID. If the feature is active, try deactivating it and make a test call. In most cases, the screen starts to respond correctly to the approach to the head.
⚠️ Note: After disabling face unlock, you will need to use a pin, pattern lock or fingerprint to log in.Make sure you remember your password before disabling biometrics.
If disabling Face ID helped, but you need to use it, you can try alternative solutions described below, such as recalibrating sensors, but for many users, the trade-off is using a fingerprint that does not conflict with the proximity sensor.
Checking the serviceability of the proximity sensor through the engineering menu
Before trying to treat software failures, you need to make sure that the Proximity Sensor itself is physically fit and capable of detecting objects at all. There is a hidden engineering menu in the MIUI shell that allows you to conduct detailed diagnostics of all the modules of the smartphone, which is the most accurate method for initial diagnosis.
To enter the test menu, open the Phone app and enter the special code ##6484#. If the code is entered correctly, the CIT menu will open. In the test list, look for the Proximity Sensor or Approximation Sensor. When you click on it, you will see a screen with numerical values and status.
The principle of checking is simple: in a calm state, when nothing covers the top of the screen, the value should be 5.0 (or close to 5). When you bring your palm or finger to the area of the dynamic conversational speaker (usually the top end or a narrow strip above the screen), the value should instantly change to 0.0. If the numbers do not change or change chaoticly, the problem may be contamination or hardware damage.
☑️ Sensor diagnostics
Importantly, some Xiaomi models use a virtual proximity sensor that relies on algorithms and a gyroscope, rather than infrared radiation, and in such cases the test may not show instantaneous response but delay, but if the screen does not respond to tight finger pressing at all in the test, software calibration is unlikely to help.
Calibration of the sensor: software reset settings
If the test in the engineering menu shows that the sensor is responding, but in real life the screen is going out too late or not going out at all, calibration is necessary. The calibration failure is the desynchronization of the software sensitivity thresholds. The system forgets which value is considered "normal" and which is "approximate." You can return the correct settings through the same engineering menu.
Return to the Proximity Sensor test using code ##6484##. Remove all items from the top of the phone so the sensor doesn't see anything. Press Calibrate or Pass if there is no separate calibration button (in some versions of MIUI, calibration is automatically performed when the test is completed).
Then, close the sensor area with your palm (the value should be 0.0) and press the calibration or confirmation button again. This action will teach the controller to understand the range of motion. After successful calibration, the phone may suggest a reboot. Be sure to do it, as the new sensory parameters are only applied after a full cycle of on.
What if calibration doesn’t help?
It is worth considering that in new versions of HyperOS access to full calibration through the CIT-The menu is sometimes blocked or hidden by the developers, in which case the only option is to completely reset the phone settings or wait for a firmware update that will fix the bugs of the sensor drivers.
The impact of protective accessories on the work of sensors
Often, smartphone owners do not even realize that the cause of the malfunction is a recently pasted protective film or glass. The proximity sensor in Xiaomi phones is very compact. If the accessory has a black opaque frame or just too thick adhesive layer at the top, it blocks the path of the infrared beam.
The beam starts to bounce off the inner surface of the protective glass and returns to the sensor, which "thinks" that the phone is already in the ear, so the screen can go out immediately when you bring the phone to your face, before you start talking, or, conversely, do not go out if the beam is scattered, especially with cheap protective glasses that do not have special cutouts for sensors.
It's easy to check the effect of the accessory: remove the security glass and wipe the screen. If the problem disappears after that, you need to replace the accessory with a better one, marked "Compatible with Proximity Sensor" or with precise cutouts. Don't try to tape the sensor with tape, this will disrupt the heat sink and other sensors.
| Type of screen protection | Impact on the sensor | Recommendation |
|---|---|---|
| Hydrogel film | Minimal, transparent to IR rays | Safe, rarely causes failures |
| Tempered glass (full glue) | High, can block the beam. | It requires verification, calibration is possible. |
| Black-framed glass | Critical, often overriding the sensor | Replacement with transparent |
| Lack of protection | Absent. | Perfect for diagnosis. |
Third-party applications for call management
If standard methods fail, you can use third-party software. There are many apps in the Play Market that intercept sensor control and force the screen lock through their algorithms, a temporary but effective solution for older models or devices with "big" firmware.
One of the popular solutions is Proximity Sensor Reset & Fix or something like Call Blacklist & Blocker, which has a screen control function, and they run on top of the call system, and once you install it, you'll have to give it permissions in the special features menu.
However, be careful: installing unnecessary apps running in the background increases battery consumption. Use this method only if the hardware calibration and removal of the protective glass did not help.
⚠️ Note: When installing apps from unverified sources, you risk handing over access to your contacts and call history to third parties.
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Third-party applications are a crutch. If the sensor is in good shape, the system must handle itself. Use the software only as a temporary measure before you update the firmware.
Hardware malfunctions and repairs
In situations where neither calibration, film removal, or Face ID disabling has helped, there is a high probability of physical failure. The proximity sensor is a microscopic module that can fail due to a fall, moisture or just factory defect. In models with screens built into the frame, replacing the sensor can be a difficult procedure.
Symptoms of hardware breakdown: In the engineering menu (#6484##), the sensor value is constantly 0.0 or constantly 5.0 and does not change at all, even when you press your finger tightly, and it can also be a sign of spontaneous switching on of the screen in your pocket or the constant burning of the screen during a conversation on speakerphone (if the sensor is “fixed”).
Repairs usually involve replacing the sensor plume or the entire top module (assembled with a speaker). In some cases, the wizards suggest turning off the sensor software permanently, but this is inconvenient: the screen will have to be locked with a button manually every time you call. For modern Xiaomi smartphones, repairing the sensor in an authorized center is the most reliable solution.