Why Xiaomi screen doesn’t lock when talking: 7 reasons and how to fix it

You’re having an important conversation on the phone, but Xiaomi’s screen persists in being active — casual touches interrupt a call, turn on speakerphone, or even complete a call — a problem familiar to many smartphone owners, and it’s found on both the budget Redmi Note and Xiaomi flagships. 13/14. V 80% In some cases, the proximity sensor is to blame, but there are other reasons - from firmware bugs to mechanical damage.

In this article, we will look at all possible scenarios for why the screen does not go out during a call, and give step-by-step diagnostic instructions, from simple checks to deep settings. 2022–2026 In the past, the problem is often associated with optimization. MIUI 14/15 And the hardware features of the new sensors, if you've tried to reboot your phone or clean the cache, you'll find solutions that go deeper.

1.How does screen locking work during a call

Before you look for the cause of the failure, it is important to understand the mechanism. In Xiaomi smartphones, the answer for locking the screen when talking is:

• 🔹 The proximity sensor is an infrared sensor that detects when the phone is held to the ear, usually next to the speaker (top of the screen).
• 🔹 software processor in MIUI — analyzes sensor signals and sends a command to turn off the display.
• 🔹 Android kernel – manages process priorities (e.g., prevents third-party applications from blocking sensors).

Activation algorithm:

1. You start the call. → system activates the approximation sensor.
2. Phone reaches your ear → The sensor detects the obstacle and sends a signal to the MIUI.
3. MIUI locks the screen and disables touch input (except volume buttons).
4. After the phone is removed, the sensor is activated again. → screen unlock.

A critical feature of Xiaomi’s 2023-2026 models is that proximity sensors are often combined with a light sensor in one module, and damage to one sensor can affect the operation of another.

Proximation sensor: diagnostics and cleaning

In 60 percent of cases, the sensor is the problem, and you can check it without disassembling the phone.

Method 1: Testing through the Engineering Menu

In the application Phone combination:

##6484##

The Manual Test Menu will open → Select Proximity Sensor. Put your hand to the top of the screen:

• ✅ If the value changes from 5 (no obstacle) to 0 (there is an obstacle), the sensor works.
• ❌ If the value is always 5 or 0, the sensor is faulty.

Method 2: Visual inspection

Take a flashlight and shine it on the top of the screen (near the speaker).

• 🔦 Dust or dirt under glass – sensor may fail due to pollution.
• 💧 Moisture traces - oxidation of contacts (relevant after water ingress).
• 🕳️ Cracks on glass above sensor – light signal scatters.

How to clean the sensor:

1. Turn off the phone.
2. Take a soft toothbrush (new!) and walk gently through the sensor area.
3. For persistent contamination, use alcohol wipes (at least 70% alcohol).
4. Don’t blow on the sensor – it can drive the dust deeper!

⚠️ Attention: On Xiaomi models 12T Redmi Note 12 Pro+ The sensor is closed with an extra layer of protection, aggressive cleaning can damage it, if after cleaning the problem remains, contact the service.

3. Software failures: from cache to firmware

If the sensor is good, but the screen is still not locked, it's the software's fault.

Phone app malfunction

Appendix com.android.dialer (or com.miui.dialer in MIUI) It can be buggy after updates:

• 🔄 Cache cleanup: Settings → Annexes → Application management → Phone. → Warehouse → Clear the cache.
• 📥 Reset application settings: In the same menu, click Reset settings (calling data will be saved).
• 🔙 Reverse updates: If the problem appeared after the update – in the menu of the application click ⋮ → Remove updates.

baga MIUI 14/15

In the firmware MIUI 14.0.4.0 and 15.0.2.0 detected bugs with the sensor signal processing:

1. Version MIUI: Settings → About the phone → version of MIUI.
2. If the version is older than 14.0.6.0 or 15.0.3.0, update via Settings. → Updating the system.
3. If there are no updates, install the beta version through the official website (for power users only!).

Alternative solution: Turn on Developer Mode and turn off Windows animation (sometimes conflicting with sensor processing). → The phone. → Version. MIUI (press 7 times) → return to → For developers → Window animation = Off..

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After the update MIUI problem remained, try resetting the network settings: Settings → SIM-maps and mobile networks → Network resets. This often helps with communication module/sensor conflicts.

4. Conflicts with protective glass and covers

Few people know, but metal-layered protective glass (e.g., "hardened" or "armored") can block the infrared signal of the proximity sensor, as can cases with magnetic fasteners or metal inserts.

How to check the effect of the cover:

1. Remove the cover and the safety glass.
2. Call your phone and check the screen lock.
3. If the problem has disappeared, the accessory is to blame.

⚠️ Note: Xiaomi 13 Ultra and Redmi models K60 Pro proximity sensor is located under the display (not above it, as usual). Here even thin glass can interfere! Use only glass with a cutout for the sensor.

5. Hardware damage: what breaks most often

If the software methods didn't work, the problem might be the hardware.

1. Damage to the sensor plume

When the phone falls or breaks down, it often leaves the plume connecting the sensor to the motherboard.

• 📵 The sensor does not respond to anything (the test is always 5).
• 🔊 Problems with the speaker (wheezing, quiet sound) – the plume often goes along with the audio module.

Solution: Disassembly and soldering/replacement of the service plume, average cost of repairs: 1,500-3,000 ₽.

Contact oxidation

If the phone was in the rain or in the bathroom, the sensor contacts could oxidize.

• 💦 The sensor will work once (it works, then it does not).
• 🔋 Fast battery discharge – oxidation increases resistance.

Diagnostics: Light a flashlight on the motherboard (if you have any experience in parsing), oxidized contacts will be green or white.

Damage to the sensor itself

The sensor may fail after:

• 🔨 Blows to the top of the phone (for example, a drop from the screen down).
• ⚡ Voltage changes (non-original charges).
• 🔥 Overheating (using the phone in direct sunlight).

How to confirm: If the sensor on the engineering menu is 0, even when the phone is lying on the table, it's defective. It'll cost 800 to 2000 to replace it. ₽ (model-wise).

6. Alternative solutions: if nothing helps

If you’ve tried everything but the screen still doesn’t lock, here are some radical methods:

1. Forced blocking through settings

V MIUI There is a hidden function of forced shutdown of the screen during the call:

1. Open the Settings. → Special facilities → Management convenience.
2. Turn on the option to automatically lock the screen when calling (some firmware called Lock during a call).
3. If there is no option, use it. ADB-Adb shell settings put global auto_lock_screen_during_call 1

2.Installation of a third-party call app

Apps like Google Phone or Truecaller have their own sensor processing algorithms.

1. Install Google Phone from the Play Market.
2. Make it the default app: Settings → Annexes → By default. → Phone.
3. In the Google Phone settings, enable Screen Lock during the call.

3.Rollback to factory firmware

If the problem occurs after the update MIUI, Go back to the previous version:

• 📥 Download the fastboot firmware version from Xiaomifirmwareupdater.com.
• 🖥️ Use the Mi Flash Tool for firmware (instructions on the Xiaomi forum).

⚠️ Attention: Firmware rollback will reset all data! pre-reverse through Settings → Additionally. → Backup and reset on models with locked bootloader (Xiaomi) 12/13/14) You will need to unlock the Bootloader.

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If you're not sure about your firmware skills, you should go to a service center, and if you don't do the right thing, you can turn your phone into a brick.

7 Prevention: How to avoid problems in the future

To ensure that the Xiaomi screen is always locked during a call, follow these rules:

• 🛡️ Use quality accessories: only original or certified glass/cases without metal inserts.
• 🔋 Avoid overheating: Do not leave your phone under the sun or charging while playing.
• 🚿 Protect from moisture: even if the model has protection IP53, Long-term exposure to moisture damages sensors.
• 🔄 Regularly update the software: in new versions MIUI Often fix sensor bugs.
• 🧹 Clean the sensor: once a month wipe the top of the screen with an alcohol wipe.

If you drop your phone frequently, consider models with an ultrasonic proximity sensor (e.g. Xiaomi). 13T They are less sensitive to mechanical damage because they have no moving parts.

FAQ: Frequent questions