How to set up a light sensor on Xiaomi: calibration and troubleshooting

The proximity sensor problem is one of the most common complaints of Xiaomi, Redmi and POCO smartphone owners. Users often face a situation when during a conversation the screen goes out prematurely or, conversely, does not turn off, which causes random buttons to be pressed with the cheek.

In most cases, the hardware is fully functional, and the problem lies solely in software failure or misalignment of calibration values. MIUI or HyperOS operating system may not correctly read the sensor readings due to accumulated cache or application conflict. It is important to understand that calibration is a process of resetting reference values, which returns the sensor's ability to respond adequately to the approach of objects.

Before you take your device to the service center, you should try to fix it yourself. There are several proven methods, from simple engineering codes to the use of specialized software. In this article, we will discuss each method in detail so that you can choose the most suitable for your model and firmware version.

The main function of the sensor is to lock the touchscreen during a phone call. If you hold the phone to your ear, the screen should go out, preventing accidental pressing. When you remove the device, the screen should light up again, and if this cycle is broken, then the calibration is down or the sensor is contaminated.

📊 Have you ever had a black screen problem when calling Xiaomi?
Yeah, the screen goes out too soon.
Yeah, the screen doesn't go out at all.
No, I'm working perfectly.
I have a different model of phone.

Preparation of the device for the calibration procedure

Before any manipulation of the system settings, it is necessary to ensure the cleanness of the smartphone surface. The upper part of the screen, where the speaker and the hidden sensor are usually located, should be free of dust, grease and finger marks. Even a thin film of dirt can distort the readings of the infrared emitter.

Be sure to remove the protective glass or film if they cover the sensor area. Some accessories manufacturers make the cutouts not accurate enough, which blocks the path of the light beam. After cleaning, wipe the screen with a soft microfiber moistened with a special tool for on-screen optics.

⚠️ Note: Do not use alcohol or aggressive solvents to wipe the top of the screen, as they may damage the oleophobic coating or leak inside the case.

It is also important to make sure that the device does not run background processes that can block access to the sensor. Close all applications and restart the smartphone before setting up, this will allow the system to clear temporary files and start all services from scratch.

Check for system updates. Sometimes the problem is known to Xiaomi developers and they release patches that fix sensor drivers. Go to settings and check the update section to rule out software bugs of the current version of MIUI.

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If you use a case with thick sidebars, make sure it doesn’t hang over the top edge of the smartphone, creating a shadow for the sensor.

Using the Engineering Menu to Configure

The most reliable and built-in way of calibrating is using the CIT engineering menu, which is available on all devices of the brand and allows you to test hardware components without installing third-party software. To enter the menu, you need to open the Phone application and enter a special code.

Type ##6484## on the keyboard. If the code is entered correctly, the CIT (Customer Information Test) menu will open. In the test list, find the "Proximity sensor" or "Proximation Sensor" option. Click on it to enter the test mode.

In the window that opens, you'll see the current sensor readings, which usually show a value of "0.0" (object not present) or "5.0" (object nearby), and if the values don't change when you put your hand up, the sensor is not working or calibrated. To start the process, press the "Calibration" button.

  • 📱 Remove your hand from the top of the screen to zero and click Calibrate».
  • ✋ Cover the sensor with your palm (without touching the screen), wait for the readings to change and press Calibrate again».
  • ✅ After the test, the message “Proximity sensor calibration success” will appear».

If automatic calibration didn't work, try resetting the sensor data through the same menu if this option is available in your firmware version, sometimes requiring multiple cycles of closing and opening with your palm to stabilize the readings.

☑️ Checking in the engineering menu

Done: 0 / 5

Calibration through the hidden menu of Phone Info

An alternative method that often helps where standard engineering menus are powerless is using a hidden menu of phone information, a technique that is particularly relevant for devices with Qualcomm and MediaTek processors, where drivers may have additional settings.

To access this menu, enter the code ##4636##. From the list that opens, select "Phone information" or "Phone information." Scroll down until you find the "Proximity sensor" section.

So here you can see the current status and, in some versions of Android, the Calibrate button. Click on it and follow the instructions on the screen. The process is similar to the previous one: remove your hand, then close the sensor. The system will record new thresholds.

MethodAccess codeDifficultyEfficiency
CIT Menu##6484##Low.Tall.
Phone Info##4636##MediumMedium
AnnexesAPK installationLow.Depends on the model.
Resetting settingsSystem menuTall.Maximum

It is important to note that on some global firmware versions, access to the 4636 menu may be limited by the manufacturer, in which case the system simply does not respond to code input, and other methods will have to be used.

⚠️ Note: Do not change other options in the Phone Info menu, such as network type or IMEI, If you're not sure what you're doing, it can lead to a loss of communication.

What do I do if the codes don't work?
Some carriers or custom firmware block input USSD-In this case, try entering the code through Google's Phone app, not through a standard call. MIUI.

Application of specialized applications

If the built-in tools don't work, Google Play apps come to the rescue. There are many utilities developed by enthusiasts to fine-tune Android sensors. One of the most popular is "Proximity Sensor Reset/Fix."

The principle of these programs is to force the calibration file to be reset and rewritten with new values. Once you install the application, launch it and put the phone on a flat horizontal surface. Make sure there is nothing above the screen.

Press the Calibrate or Reset button. The app will ask you to cover the sensor with your hand and then remove it. Once the procedure is complete, be sure to fully reboot the device so that the changes take effect.

  • 📲 Download the proven app for calibrating sensors.
  • 🧹 Clear the Phone and Contacts app cache before launching.
  • 🔄 Be sure to restart your smartphone after calibration.

It’s worth remembering that third-party applications vary in performance depending on the processor model, and on devices with MediaTek chips, they perform better than on Snapdragon, due to differences in driver architecture.

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Third-party apps are the “last chance” before a full reset, but they don’t guarantee 100% results on all models.

Diagnostics of hardware faults

It's not always the software that's the problem. If none of the software methods work, there's a high probability of a physical malfunction, and the proximity sensor is an optical device, and it can fail because of impact, moisture, or factory failure.

Take a close look at the top speaker area, and sometimes you get dust or pile from your pocket that completely covers the sensor, and try to clean that area with a soft brush or pear to clean the optics.

It's also worth checking if the display module has been replaced in an unofficial service. Cheap copies of screens often have poor-quality sensors or incorrect installation geometry, which makes them not match the software calibrations of the system.

If the sensor is intermittently working, it may indicate a running plume, in which case a slight tap on the top corner of the smartphone may temporarily restore contact, a clear sign of a need for repair.

⚠️ Warning: If the phone falls into the water, even if it is protected by standard IP, The sensor can oxidize, and then the software calibration is useless.

How to check the sensor without programs?
Call your answering machine number or a friend. Hold your phone to your ear. If the screen only goes out when you press your phone tightly, but doesn't respond to a light approach, the sensor needs to be replaced.

Radical measures: complete resetting of settings

When all methods have been tried and the problem persists, the last software option is a full reset (Hard Reset), which will remove all data from the device, so be sure to back up important information in the Xiaomi Cloud or on your computer.

Go to the "Settings" menu» → «The phone» → «Settings reset. Select "Erase all data." Once the phone is restarted, it will return to factory status, and all system files, including sensor configuration, will be rewritten again.

Often, after a reset, the problem disappears as conflicting applications and damaged system libraries are removed, but if the sensor does not behave correctly, the probability of hardware failure is 99%.

Remember that after resetting, it will take time to initially set up and index the files. During the first hours of operation, the sensor may behave unstable until the system completes the background optimization processes.

  • 💾 Make a complete backup of the data.
  • 🔋 Charge your phone to at least 60% before resetting.
  • ⏳ Give me a phone. 30-40 minutes after activation of stabilization.

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After reset, do not install all applications at once. Check the sensor on a clean system to exclude the influence of third-party software.

Frequently Asked Questions (FAQ)

Why does the light sensor not work after the MIUI update?
Operating system updates often contain new drivers or changes in sensor algorithms, and sometimes new settings conflict with the old calibration, in which case recalibration through the engineering menu usually solves the problem.
Can the protective film affect the operation of the sensor?
Yes, that's a very common reason. If the film is black, or if it's just too thick in the top speaker, it blocks the infrared beam. Try to take the film and check the sensor.
Is constant calibration harmful to the sensor?
No, software calibration doesn't wear out the sensor, because it's a software operation to write values to memory, but if the sensor is physically defective, constant calibration attempts won't restore it to work.
What if the screen goes out in your pocket without a call?
This means that the sensor is too sensitive or locked, check if there is a pile in your pocket covering the top of the phone, and try to turn off the "Mode in your pocket" feature in the lock settings, if you have such an option in your version of MIUI.
Will the phone flashing help?
Flashing to a global or Chinese version can help if the problem is caused by a software bug of a specific regional firmware, but it is a complex procedure that requires unlocking the bootloader, and it does not guarantee a solution if it is a hardware problem.