Xiaomi’s Poco smartphones are famous for their excellent price-performance ratio, but users often face the nuances of the touch panel. One of the most common complaints of Poco M3 owners is the incorrect operation of the proximity sensor, which should extinguish the screen during a conversation. If the display continues to burn when you hold the phone to your ear, you will inevitably press extra buttons, reset calls or turn on the retention mode.
Most of the time, the problem isn't physical failure, but software failure or calibration failure of the MIUI system. The proximity sensor is an infrared sensor located at the top of the body that measures the distance to the object. When you hold the phone to your head, the sensor picks up the obstacle and sends the system a signal to turn off the touchscreen and extinguish the image to save energy and prevent false presses. Ignoring this feature makes comfortable communication almost impossible.
Fortunately, Android and MIUI have hidden engineering menus and standard settings to diagnose and fix things without going to the service center. Below, we’ll take a look at all the methods available to activate and fine-tune this important component so that your Poco M3 can work like a watch again.
Checking physical health and screen cleanliness
Before you go into deep system settings, you need to rule out the banal physical reasons. Often the sensor is simply closed with a layer of dust, greasy fingerprints or a poor protective glass that covers up infrared radiation. In the Poco M3 model, the sensor is located in a narrow strip above the speaker, and even the slightest contamination can distort its readings, making the system think that the phone is always in the ear.
Carefully wipe the top of the screen with a soft microfiber dipped in a special electronics solution. Pay attention to the protective glass: if it is glued curved or has a factory defect in the form of a black dot above the sensor, it will have to be replaced. Physical cleanliness is the first condition for the correct operation of any optical or infrared sensor.
- 🧼 Carefully degrease the area above the talking speaker with an alcohol napkin.
- 📱 Check if the protective glass or film covers the sensor area.
- 🔦 Illuminate the flashlight into the sensor area to make sure there are no visible cracks.
⚠️ Warning: Do not use aggressive household chemicals or abrasive materials to clean the screen, as this can damage the oleophobic coating and aggravate the problem with the senses! M3 The proximity sensor is directly below the screen, so any contamination on the display surface is critical.
If the problem persists after cleaning, it's the software part, and then we go to the engineering menu.
Diagnostics through CIT Engineering Menu
The most reliable way to check the status of the sensor and conduct its initial calibration is using the built-in CIT (Customer Integration Test) Menu, a tool created by Xiaomi engineers to test all smartphone modules before sale, accessed through the standard Phone application.
To enter the diagnostic mode, you need to enter a special combination of characters. Dial on the call keyboard code ##6484##. If done correctly, a menu will open with a list of all tests. Find the Proximity Sensor or Approximation Sensor item in the list. When you click on it, you will see the current sensor readings. When there is nothing closing the top of the screen, the value should be 5.0 (or Far). If you close the top of the screen, the value should change to 0.0 (or Near).
If the values don't change or change randomly, it's a software failure that can often be fixed right here. In some firmware versions, the Calibration button is available. Press it and follow the instructions on the screen: you usually need to remove your hand from the screen and then close the sensor. After successful calibration, the system will save the new reference values.
☑️ Sensor diagnostics
It's important to understand that the engineering menu is a powerful tool, and changing the parameters here affects the hardware at a low level. Be careful when you press the buttons, so that you don't accidentally reset other important settings.
Set up via the hidden Phone Info menu
If the standard CIT menu fails or lacks calibration, you can take advantage of the deeper level of Android settings available through the Phone Info menu.This method often helps activate the sensor if it has been software-disabled or malfunctions after a system update.
Unlike the previous method, you'll need to type in another code here: Open the Phone app and type ##4636##. You'll see the Check menu. Select Phone information. Scroll down to PPR Settings or look for options related to Proximity Sensor. There may be a switch that allows you to force the sensor on or off.
In some cases, resetting the sensor settings through this menu helps: Find the Turn off proximity sensor button, press it, and then turn the sensor back on. This action restarts the device driver, which can eliminate the freeze of the service responsible for screen response.
- 📞 Enter the code ##4636## in the dialing app.
- 📱 Select the section "Phone information).
- 🔄 Find the sensor switch and complete the off/on cycle.
What if the code doesn't work?
Reset sensor settings via ADB (for advanced)
For users who are not afraid of the command line and want to reset the sensor to factory settings, there is a method using USB debugging and the ADB tool (Android Debug Bridge), which is effective when software failures do not allow you to fix the problem with standard means.
First, you need to activate the developer mode. Go to Settings. → About the phone and seven times quickly click on the build number MIUI. Then in the advanced settings, turn on “Debugging by” USB». Connect your phone to your computer, install drivers ADB and enter a command to reset the sensor calibration.
adb shell content insert --uri content://settings/system --bind name:s:proximity_off --bind value:i:0This command compels you to set the sensor to zero, which actually activates it if it's locked by the system flag. Once you've done the command, be sure to restart the device. This method requires caution, because working with ADB gives you broad permissions to access the system.
⚠️ Attention: Use of teams ADB This can cause the system to work in an unstable way if you type in the wrong way. Make sure you copy the commands accurately, without unnecessary symbols.
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If you are not confident in your abilities when working with ADB, it is better to use standard methods of calibration through CIT, as they are safer for the average user.
Impact of Updates and Third-Party Apps
Often, a proximity sensor problem on the Poco M3 occurs immediately after an operating system update or a specific software installation. Newer versions of MIUI may contain bugs that conflict with sensor drivers. In addition, various applications for managing calls, recording conversations or “smart” shells can intercept control of the sensor.
If you're looking at when the problem occurred, if you're up to date, you're waiting for a patch from the developers, or you're going to roll back to the previous firmware, if you're up to date, try removing the software you've installed, especially the software that has access to the microphone and phone.
It's also worth checking your "pocket mode" settings. Some design themes or launchers have a feature that mimics sensor performance that may not work properly. Disable all third-party themes and return the standard launcher for verification.
Software conflicts are one of the hardest things to diagnose, and sometimes it's just a complete data cleanup or factory reset, but that's a last resort.
Table of basic codes and actions for Xiaomi Poco M3
For ease of perception, we will collect all the key commands and actions in a single table, which will help you quickly navigate and choose the right method of solving the problem without having to re-read the entire text.
| Action. | Code/The Way | Description of the outcome |
|---|---|---|
| CIT's Engineering Menu | ##6484## | Full diagnostics of all sensors, calibration |
| Phone Info menu | ##4636## | Deep setting of phone and sensor settings |
| Reset via ADB | adb shell ... | Forced resetting of sensor shutdown flag |
| Settings of the topic | Settings → Screen | Disabling modes “in the pocket” in third-party themes |
Using these codes is standard practice for technicians and advanced users, and you don't have to remember them, but you have to have access to that information at the right time.
Frequently Asked Questions (FAQ)
Why does the screen go out when I just hold my phone in my hand?
Can broken glass cause the sensor to break down?
Are sensor settings reset when reset to factory?
Does the sensor have an effect on the antispy sticker?
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In 90% of cases, the sensor problem on the Poco M3 is solved by a thorough screen cleaning and recalibration through the CIT engineering menu.
To sum up, turning on and configuring the proximity sensor on the Xiaomi Poco M3 is a solvable task: Start with device hygiene and simple calibration, and chances are your smartphone will again respond correctly to your actions during calls.