Xiaomi, Redmi and Poco are all famous for their functionality, but owners often face an annoying problem: the screen does not go out during a conversation or, conversely, suddenly turns off when you lift it to the ear. This is direct evidence of the incorrect operation of the proximity sensor. Ignoring this malfunction not only causes discomfort, but can lead to accidental pressing, reset calls or rapid battery discharge due to the constantly burning screen.
The problem can be a software failure that requires simple calibration, as well as physical damage to the component. In this article, we will examine all available diagnostic methods, from simple visual checks to the use of hidden engineering codes. Understanding how this sensor works will help you quickly determine whether a replacement part or software adjustment is enough.
Principle of operation and location of the sensor
The proximity sensor is an optical sensor that emits infrared light and measures its reflection from nearby objects. In Xiaomi smartphones, it is most often located at the top of the front panel, next to the conversational speaker. In older models, it was a separate visible element, but in modern devices it is often hidden under a protective glass or integrated into the housing.
The main purpose of this component is to lock the touch screen (touch screen) during a conversation, which prevents accidental touches with the cheek or ear that could put a hold call, turn on speakerphone or complete a call. When you remove the phone from your ear, the sensor detects the absence of reflected light and activates the display again.
It is important to understand that external factors can affect the operation of the sensor: dirt, greasy spots, thick protective glass or improperly pasted film can distort infrared radiation. False positives often arise precisely from pollution in the upper end of the smartphone.
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Use microfiber to clean the top of the screen regularly, especially the area above the display, to avoid false sensor alerts.
If you notice that the screen is behaving unpredictably, the first thing you do is check the surface cleanliness, sometimes just wipe the speaker area to make the sensor work properly, but if the cleaning doesn't work, you'll need a deeper diagnosis.
Primary visual diagnosis and simple tests
Before you get into complex settings, you should do a basic check that requires no special skills. The easiest way is to make a trial call. Call any number (for example, the operator's support service or your other phone) and hold the device to your ear.
The screen should go out almost instantly. If the screen goes out, but then lights up again while the phone is near the ear, or does not go out at all, this is a sign of malfunction. Also note the brightness: in some cases, the screen does not go out completely, but only reduces the brightness to a minimum, which is also an option, but less effective for saving charge.
- 📱 Call someone and hold the phone to your face: the screen should go out.
- 👋 Remove the phone from your ear: the screen should light up and unlock.
- 🧼 Wipe the top of the screen: remove dust and fat from the speaker area.
- 🛡️ Check the protective glass: it should not overlap the touch element.
A common problem for Xiaomi owners is poor-quality protective glass. If the glass covers the sensor area (even partially) or has a black frame that overlaps the sensor, the correct operation is impossible, in such cases only replacing the accessory with an original or special one, with a cutout for the sensor helps.
Use of the Engineering Menu to Check
The MIUI and HyperOS shells include a built-in engineering menu that allows detailed diagnostics of all components, including the Proximity Sensor. This is the most reliable software method of verification.
Open the Phone app and dial ##6484##. If the code didn't work, try ##4636## or go to Settings → About Phone → Kernel Version (click 5-7 times). In the CIT (Customer Integration Test) menu that opens, find Proximity Sensor.
Inside the test, you'll see a numerical value. Usually, when nothing covers the top of the phone, it should be 5.0 (or close to 0, depending on the software version). When you close the sensor with your hand, the value should change to 0.0. If the numbers "jump" or not change at all, this indicates a problem.
⚠️ Warning: Do not change the settings in other sections of the engineering menu unless you are sure of their purpose.
For precise calibration, there's often a Calibrate button on the same menu. Press it, remove your hand from the sensor, wait for the Pass message, then close the sensor and press Pass again. After successful calibration, restart the device.
☑️ Checking in the engineering menu
Exception settings and system parameters
Sometimes the sensor is fine, but the system misinterprets its data because of power saving settings or application conflicts. MIUI has a Pocket Mode feature that uses the proximity sensor to prevent accidental taps. If this function is not working properly, it can lock the screen.
Try disabling this feature to see if the problem goes away. Go to Settings → Lock and Protection → Mode in your pocket and turn off the switch. This will help you know if the problem is system or hardware. It's also worth checking for system updates, as Xiaomi often releases patches that fix sensor bugs.
Another important aspect is app resolution: Some messengers (like Telegram or WhatsApp) have their own proximity sensor settings, go to the app settings and look for options related to the sensor or voice playback.
| Parameter | Normal condition | Sign of malfunction |
|---|---|---|
| Reaction on the hand | The screen goes off instantly. | Delay or lack of response |
| Meaning at CIT | Changes 5.0. ↔ 0.0 | Value is constantly or jumping |
| Protective glass | It doesn't cover the sensor. | Black frame on the sensor |
| Dirt/Dust | Absent. | Visible pollution in the grid |
If only one app has a problem after you turn off Mode in Your Pocket, it's probably because of optimization, and if the screen goes out chaoticly in all apps and calls, it's because of hardware or global firmware failure.
Hidden Developer Settings
Third-party calibration applications
If Xiaomi's built-in tools don't work, you can use third-party software from Google Play. There are many utilities, such as Proximity Sensor Reset/Fix or Sensor Test, that allow for deeper calibration that is sometimes not available on the standard menu.
The way these applications work is similar: they request access to the sensor, they suggest that you close it with your hand, then remove it and fix the new thresholds. After the calibration procedure, the application may require a reboot, which is especially true for devices that have had a flashing or resetting to factory settings.
But be careful: some apps require.root permissions to work properly; without superuser rights, they can only diagnose a problem, but not fix it; and read reviews carefully before installing them so you don't download malicious software.
⚠️ Note: Apps with access to root rights may void warranty if misused. Be careful when granting extended permissions.
Using third-party software is a last resort before you go to the service, and if neither calibration through the engineering menu nor third-party applications yield results, the probability of hardware failure is as high as 90%.
Hardware problems and physical repairs
When software methods are exhausted, you have to consider physical reasons. The proximity sensor on Xiaomi can fail due to a fall, moisture or just wear. In some models (for example, the old Redmi Note), the sensor was placed on a plume that could move away.
In modern smartphones, the sensor is often embedded in the screen module or soldered to the board. If you drop the phone and then the sensor stops working, most likely, the plume or the sensor itself is damaged, and a common cause is moisture entering the area of the speaker, which leads to oxidation of the contacts.
Self-repair requires electronic disassembly skills, removing the back cover (or screen, depending on the design), disabling the battery and checking the connection of the sensor plume, sometimes just reconnect the connector or clean the contacts with alcohol.
- 🔧 Disassembly: Requires heating of the body and suckers.
- 🔌 Schleife: Check connector planting density.
- 💧 Moisture: Check the fee for oxides.
- 🔄 Replacement: The sensor is often assembled with the top plume.
If you're not confident, you'd better not take the risk, because if you disassemble the parts incorrectly, you might damage other components, like the display plume or the battery, and you might want to go to an authorized service center.
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If calibration and cleaning did not help, and in the engineering menu the sensor does not respond to closing with the hand, a replacement of the hardware module is required.