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

Why the Poco X3’s proximity sensor may not work – and how to fix it

The proximity sensor in Xiaomi Poco X3 is responsible for automatically turning off the screen during a phone call when you hold the device to your ear. This prevents accidental tapping and saves battery power. However, many users face the problem when the sensor stops responding: the screen does not go out when you call, or, conversely, does not turn back on, the causes can be different from software failures to physical damage.

In this article, we will discuss all ways to turn on and configure the proximity sensor on Poco. X3, And you'll learn how to tell the difference between a sensor malfunction and a firmware error, and what to do if no method works. MIUI, including global and Chinese firmware.

Where is the proximity sensor on Xiaomi Poco X3

In the Xiaomi Poco X3, the proximity sensor is located at the top of the screen, next to the front camera. It is a small sensor that works on the basis of infrared radiation. It detects the distance to an object (for example, your ear) and sends a signal to the system to turn off the display.

To find its exact location, look at the top of the screen -- usually hidden under the black display array and not visible -- and on some devices, you can detect it by a barely visible hole on the left or right of the speaker. Importantly, don't confuse it with the light sensor, which is also located at the top, but is responsible for automatic brightness control.

• 📍 Location: The top of the screen, next to the front camera (usually left).
• 🔍 What it looks like: a small transparent or black hole (may be hidden under glass).
• ⚡ Principle of operation: infrared sensor that reacts to the approach of the object at a distance of 2-5 cm.

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If your Poco X3 has a protective film or glass installed, make sure it doesn't cover the sensor area.

How to turn on the proximity sensor through the MIUI settings

In most cases, the proximity sensor on the Poco X3 is activated by default, but it depends on the settings of phone calls. If the screen does not go out during a conversation, check the following parameters first:

1. Open the Settings app.
2. Go to the Appendix section → Application management.
3. Find your phone in the list and select it.
4. Slip on the Permission.
5. Make sure that the resolution of the body sensors (or proximity sensor) is turned on.

If the resolution is already active but the sensor is not working, check the call settings:

1. Open the Phone app.
2. Click on the three dots in the top right corner and select Settings.
3. Go to Call Settings → Additionally.
4. Activate the option to turn off the screen when approaching (the name may vary depending on the version of MIUI).

Make sure that the "body sensors" permission is enabled for the "Phone" app |

Check your call settings for the option "Switch off screen when approaching" |

Reboot your phone after changing your settings |

Test the sensor during a real call-->

Checking the proximity sensor through the engineering menu (codes)

If the settings don't work, the sensor may be malfunctioning or disabled at the system level. To check its operation, use the engineering menu (hidden service mode).

1. Open the Phone app.
2. Enter the combination: ##6484## (for sensor test) or #4636## (general engineering menu).
3. In the menu that opens, select Sensor Test.
4. Find the Proximity Sensor string.
5. Raise your hand to the top of the screen – the value should change from 5.00 (no obstacle) to 0.00 (object detected).

If the values do not change or an error is displayed, the sensor is faulty. On some MIUI firmware, the engineering menu may be blocked - in this case, use third-party testing applications (for example, Phone Doctor Plus or CPU-Z).

Only when problems arise|

Once a month for prevention |

Never checked |

I don't know how to do that.-->

Resetting and calibration of the proximity sensor

If the sensor is not working properly (for example, the screen does not turn on after a call), try recalibrating it.

1. Go to Settings. → The phone.
2. Find the MIUI version and tap it 7-10 times until you get a message.
3. Return to the main settings menu and open Additional → for developers.
4. Find the USB debugging option and activate it.
5. Connect your phone to your PC and use it ADB-Adb shell settings put global settings proximity_delay 0

If ADB is not available, try an alternative method:

• 🔄 Soft reset: restart your phone and check the sensor.
• 🧹 Cache Clearing: in the Phone app settings, click Clear Cache.
• ⚙️ Resetting all settings: Settings → Additionally. → Resetting settings (does not delete data, but resets system settings).

⚠️ Attention: Do not use commands ADB, If you're not sure what they're doing, incorrect changes can cause system failures.

Frequent causes of proximity sensor failure

If the sensor stopped working suddenly, the most likely causes are:

• 📱 Software failure: conflict after update MIUI or installing third-party applications.
• 💥 Physical damage: phone fall, moisture or dust hit under glass.
• 🔌 Sensor pollution: Fat, dirt, or protective film blocks infrared signal.
• 🔄 Incorrect firmware: install custom software without sensor support.
• 🔋 Battery discharge: At critical charge levels, some sensors are turned off to save energy.

To rule out hardware fault, try testing the sensor in safe mode:

1. Press the power button and hold it until the turn off menu appears.
2. Slip and hold the "Switch off" item until the prompt to go to safe mode appears.
3. Confirm the action and wait for the reboot.
4. In safe mode, check the sensor, and if it's running, there's a problem in one of the apps that you've installed.

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If the sensor doesn't work even in safe mode, the reason is probably hardware.

Replacement of the proximity sensor on Xiaomi Poco X3

If all software methods have been tried, but the sensor is still not functioning, it will need to be replaced. In the Poco X3, the proximity sensor is soldered into the tail of the front camera, so you can not replace it separately - you will have to change the entire module. The cost of repairs in service centers varies from 1,500 to 3,000 rubles (depending on the region and status of the service).

Self-replacement is possible, but requires experience with electronics.

• 🛠️ Set of screwdrivers (star, cross).
• 🔥 Hair dryer for heating the glue (or a mediator for opening the case accurately).
• 🔧 New front camera plume with sensor (can be ordered on AliExpress or in specialized stores).
• 🧲 Antistatic bracelet (to protect against static electricity).

You can find step-by-step instructions for disassembling the Poco X3 on YouTube (we recommend Xiaomi Repair or Fixez channels), but remember: self-repairing is unwarranted (if it is still valid) and can lead to additional damage.

⚠️ Warning: Replacing the front camera plume risks damaging the flexible contacts or display. If you are unsure of your skills, trust the repair to the professionals.

Frequently Asked Questions (FAQ)