Approximation Sensor on Xiaomi Poco X3 Pro: how to turn on and configure

The proximity sensor problem on Xiaomi smartphones and its Poco sub-brand is one of the most talked-about issues among users, and the Poco X3 Pro is no exception, often facing a phone call where the screen doesn’t go out when you hold the phone to your ear, or the conversation is interrupted by accidental cheekstrokes, which creates serious inconveniences, interfering with normal communication and consuming battery power.

It's important to understand that in most cases, the sensor is not "off" software in the usual sense of the word, but is not working correctly due to calibration failures or physical obstacles. The proximity sensor is an infrared sensor that responds to reflected light from close-up objects. In the Poco X3 Pro, it is hidden under the display or located in a thin slot of the speaker, making it sensitive to contamination and software errors of the MIUI system.

In this detailed guide, we’ll look at all possible troubleshooting options, from simple speaker cleaning to deep calibration through an engineering menu, how to check the sensor’s performance, whether you need to include special features in your settings, and what to do if the screen stops responding to an approach after a firmware update.

Check the performance of the sensor through the engineering menu

Before you try to turn on or configure a sensor, you need to make sure it is physically fit and defined by the system.In the MIUI shell on which the Poco X3 Pro is based, there is a hidden engineering menu available through a standard dialer. This is the most reliable way to initial diagnosis without installing third-party applications.

To enter the test mode, open the Phone app and dial the combination ##6484##. If the menu does not open, try the alternative code ##4636##, although the former option is more informative for Xiaomi. In the CIT (Customer Information Test) list that opens, look for the "Proximity sensor" or "Proximity Sensor." When you click on it, you will see a screen with numerical values that change when you close the top of the screen with your hand.

If the values change (e.g., from 5.0 to 0.0), then the hardware is fine, and the problem lies in the software settings or calibration. If the numbers are static, even when you completely cover the area of the speaker, it may indicate physical damage to the plume or the sensor itself.

It is worth noting that in some firmware versions, CIT access may be restricted or the test may show false positives, in which case it is worth rechecking the data through third-party utilities, but the baseline test using ##6484## remains the gold standard for quick verification.

The main causes of failures in the sensor

Understanding the cause of a malfunction is key. Poco X3 Pro owners often sin on "glutty" firmware, but statistics show that physical factors are more common. Security glass or film, sloppy, can block infrared radiation. Even a microscopic crack in the speaker area can distort the sensor readings.

The second common cause is software conflict: After updating MIUI or installing "heavy" design themes, the system file that handles the sensor data may not work properly, and the case frame also has an impact: if the sides are too high, they can mechanically interfere with the sensor's operation, creating the illusion of constant approach.

⚠️ Attention: Using cheap, black-framed protective glasses that are wider than the original often results in a full sensor lock.

And then there's the software bugs in the shell itself, and sometimes after an upgrade, the system forgets the calibration data, and in that case, just rebooting it won't help, you'll need to reset the settings or recalibrate it through the engineering menu, which we'll talk about later, and you'll also be affected by the dust and pile in the speaker grid that builds up over time.

Calibration of the proximity sensor through the engineering menu

If the test shows that the sensor is responding but is not doing it correctly (e.g., the screen goes out too soon or too late), calibration is necessary.This is a process where you train the system to understand what is near and what is far. In the Poco X3 Pro, this is done through the same CIT menu we used to test.

Enter the testing menu with code ##6484## and select "Proximity sensor." The screen will show two buttons: "Pass" and "Fail", as well as current readings. To start the calibration, you usually need to press the "Calibrate" button (if available in your version of CIT), or simply follow the instructions on the screen: remove your hand from the screen, wait for the signal, then close the sensor with your hand and remove it again.

In some versions of MIUI, the process is automated: you just press "Start," remove your hand, then close the top of the screen with your palm and wait for a vibration or a beep. Once successfully completed, the system will give a success message. If the calibration does not pass the first time, repeat the procedure 2-3 times to ensure that the screen surface is clean.

CIT login code: ##6484###


The Way: CIT -> Proximity Sensor -> Calibrate

It's important to calibrate in bright, but not direct sunlight. The infrared rays of the sun can blind the sensor, and the calibration will be incorrect, and it's best to do it indoors under artificial light.

Phone settings and applications for calls

Often the problem is not with the sensor itself, but with the settings of the Phone app or Xiaomi system settings. Newer versions of MIUI have introduced the “Approach Sensor Control” feature, which can conflict with standard sensor operation. Check the settings in the Settings section → Phone application → Incoming calls.

You can activate the "Block in your pocket" or similar option here. Try to turn it off and check if the screen behavior changes during the call. Also, it is worth clearing the cache of the Phone application: go to Settings → Apps → All apps → Phone → Memory → Clear. This will not delete your contacts, but will reset temporary files that may have caused the crash.

If you use third-party applications to make calls (like Truecaller or Google Phone instead of the standard one), make sure they have all the necessary permissions. Sometimes the system blocks third-party software from accessing the proximity sensor in order to save energy.

• 📱 Check if the “In your pocket” mode is included in the screen settings.
• 📞 Try temporarily disabling proximity in the settings of the call app itself, if such an option is available.
• 🧹 Clear the cache of the system application "Phone" and "Contacts».

You should also pay attention to the “Mode in your pocket” feature, which if it doesn’t work properly, the phone may think it’s in the dark and closed, locking the screen without calling. Turn off this feature in the Settings menu → Lock the screen for testing.

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If the sensor stopped working after the MIUI update, try resetting the network settings: Settings → Connection and Sharing → Reset Wi-Fi, mobile network and Bluetooth. This often resolves driver conflicts.

Use of third-party applications for calibration

Xiaomi's built-in tools aren't always available or work properly, and in these cases, specialized apps from the Google Play Store come to the rescue. One of the most popular and proven tools is the "Proximity Sensor Reset & Test," which allows you to perform deep calibration that the standard menu sometimes ignores.

Once you install the app, run it and follow the instructions. It will ask you to close the sensor, then open it, and based on that data, it will create a new calibration profile. Some applications also allow you to force the sensor to turn on or off, which can be useful for diagnostics.

However, be careful: using third-party applications that require root rights can cause system disruption. Most modern calibrators work without superuser rights using standard Android APIs. If the application requires root for easy calibration, it is better to look for an alternative.

Using these utilities is a good way to avoid going to a service center if the problem is software-based, but if no application sees any changes when the screen is closed, the problem is likely hardware.

Hardware problems and physical repairs

If software methods, calibration and resetting didn't work, you'll have to consider a physical intervention. In the Poco X3 Pro, the proximity sensor is integrated into the display plume or located on a separate board under the speaker. A common problem with this model is the plume's drifting away after falls or due to a manufacturing defect.

Also worth checking is the speaker's status. The speaker grid in the Poco X3 Pro is small and easily clogged. Sometimes it's enough to clean it with a soft toothbrush (without pressing) to make the sensor come alive. Dust creates a dense barrier to infrared radiation.

⚠️ Attention: Self-disassembly Poco X3 The Pro is complicated by the glass back cover and a lot of screws. Inept actions can damage the plumes or damage the tightness of the body.

In the worst case, if the sensor is burned or malfunctioning, it requires professional repair. In service centers, either the entire display module is changed (since the sensor is often built into it), or the component is soldered on the board. In the Poco X3 Pro model, it is the departure of the contacts of the display plume from the motherboard that is a common cause of sensor failure.

There is a temporary solution for those who don't want to carry the phone for repair right now: using a headset or hands-free by default, which bypasses the need for a sensor, since the screen doesn't go out when the hands-free mode is in place.

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If the speaker cleaning and calibration did not help, 80% of the time, the display plume is soldered or the screen module itself is replaced.

Frequently Asked Questions (FAQ)