Approximate sensor on Xiaomi Poco M3: full instructions for configuring and troubleshooting

Why is the proximity sensor on the Poco M3 so important?

The proximity sensor in the Xiaomi Poco M3 is a small but critical element that is responsible for automatically turning off the screen during a phone call. When you hold your smartphone to your ear, the sensor registers the obstacle and extinguishes the display, preventing accidental tapping of the cheek or ear. However, many users are faced with the fact that the sensor does not work correctly: the screen does not turn off in time, reacts with a delay or, on the contrary, it works too early.

Proximity sensor problems can occur for a number of reasons, from simple sensor contamination to firmware failures. In this article, we will look at all the ways to set up, calibrate and diagnose a Poco M3 sensor, including hidden MIUI features that are rarely mentioned in standard instructions. You will learn how to check the sensor’s performance without special applications, how hardware malfunctions differ from software, and what to do if the sensor stops working after a system update.

We'll focus on the hidden MIUI settings that allow you to manually calibrate the sensor, and consider alternative ways to solve the problem, from resetting the settings to using the engineering menu. If you notice that during a call the screen does not go out or, conversely, turns off too sharply, this instruction will help return the smartphone to normal operation.

Where is the proximity sensor on the Poco M3?

Before you start setting up, it’s important to understand where the sensor is physically located. On the Xiaomi Poco M3, the proximity sensor is integrated into the top of the screen, next to the front camera and speaker, and the exact location can be determined by a small hole or transparent area under the glass (usually to the left or right of the camera).

Here's how to find him:

• 🔍 Visually: Turn on the flashlight and shine a light on the top of the screen – the sensor will look like a small dark spot.
• 📱 Software: Open the Phone app, dial ##6484## (hardware component test) and select Proximity Sensor.
• 🛠️ Physically: if you remove the protective glass, the sensor will be under a black frame, next to the infrared port (if you have one in your modification).

Importantly, on some versions of the Poco M3 (such as those with firmware for the global market), the sensor can be hidden under opaque film, making it difficult to detect visually, in which case it is better to rely on software verification methods.

How to check the operation of the proximity sensor?

Before you set up the sensor, make sure it works at all, and there are a number of ways to do this, from standard MIUI tools to third-party applications.

Method 1: Integrated MIUI test

The easiest way is to use the hidden test menu:

1. Open the Phone app.
2. Type ##6484## (or #4636## → Hardware Testing → Sensors).
3. Select Proximity Sensor.
4. Close the sensor with your hand – the value should change from 5.0 cm (or similar) to 0.0 cm.

Method 2: Apps from Google Play

If the standard test doesn’t work, install one of these apps:

• 📊 CPU-Z — It shows the status of all sensors, including the proximity sensor.
• 🔧 Sensor Test – visualizes the sensor in real time.
• 📱 Phone Doctor Plus – comprehensive diagnostics of hardware components.

If the sensor does not respond to obstacles during testing, the problem may be:

• 🧹 Sensor pollution (dust, fat, protective film).
• 🔄 Firmware failure (especially after update) MIUI).
• 🔧 Hardware failure (damage to the plume or the sensor itself).

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If the sensor doesn’t respond to the tests, try restarting the smartphone in safe mode (press the power button → “Reboot in safe mode”). If the sensor is working in safe mode, the problem is in one of the installed applications.

Manual calibration of the proximity sensor

If the sensor is working but not working properly (e.g., the screen goes out too early or doesn't turn off in time), it can be calibrated manually. MIUI has hidden settings for this.

Method 1: Through the Engineering Menu

To access the engineering menu:

1. Open the Settings. → The phone.
2. Click 7 times on the MIUI version to activate the developer mode.
3. Back to Settings → Additionally. → For developers.
4. Activate the option to Enable the Engineering Menu.
5. Open the Phone app and dial ##36446337##.
6. Go to Hardware Testing → Sensor → Proximity Sensor.
7. Press Calibrate and follow the instructions on the screen (usually close the sensor with your hand and hold it for a few seconds).

Method 2: Using Sensor Calibration

If the engineering menu is not available, use third-party utilities:

• 📲 Install Sensor Calibration from Google Play.
• 🔍 Select Proximity Sensor from the list.
• 🖱️ Follow the on-screen prompts (usually you need to close the sensor and hold for 5-10 seconds).

After calibration, restart your smartphone and check the sensor during the call. If the problem persists, proceed to the next section.

Make sure there is no dust or film on the sensor.|

Close all background applications |

Connect your smartphone to charge (in case of failure)|

Make a backup copy of important data-->

Remediation of programme failures

If the proximity sensor stopped working after updating MIUI or installing a new application, the problem is likely software.

1. Resetting sensor settings

Sometimes it helps to reset the settings of all sensors:

1. Go to Settings → Applications → Application Management.
2. Find the settings (system application) and open it.
3. Press Warehouse. → Clear the data.
4. Reboot your smartphone.

2.Return of MIUI Update

If the sensor breaks down after the firmware update:

• 📥 Download the previous version MIUI POCO M3 from the official Xiaomi website.
• 🔄 Go to Settings. → The phone. → Updating the system → Three dots up there. → Select a firmware file.
• 📁 Specify the downloaded file and confirm the rollback.

Important: rolling back the firmware will reset all smartphone settings to factory. Pre-back up through Settings → Additional → Backup and Reset.

3. Removal of conflicting applications

Some applications (especially those that work with calls or screens) can block the sensor.

• 🚫 Remove recently installed call apps (e.g. Truecaller, Drupe).
• 🔍 Check the permissions in Settings → Annexes → Permits → Other permits → Changes in system settings.
• 🛡️ Launch your smartphone in safe mode and check the sensor.

Cleaning the proximity sensor: step-by-step instructions

One of the most common causes of sensor failure is pollution, because dust, greasy skin marks, or residues of protective film can block the infrared signal, and cleaning the sensor often solves the problem without complex manipulation.

What you need:

• 🧴 Alcohol wipes (or cotton swab) + isopropyl alcohol 70%+).
• 💨 Compressed air canister (optional, for dust removal).
• 🔍 Loop or flashlight (to see the sensor accurately).
• 🧼 Soft lilac-free fabric (microfibra).

Cleaning process:

1. Turn off your smartphone and remove it. SIM-Memory card (if they interfere with the).
2. With the flashlight, find the sensor (see the section "Where is the sensor").
3. Gently wipe the sensor area with a dry cotton swab to remove large dust particles.
4. Soak the napkin with alcohol and move it lightly, clean the sensor.
5. Let the alcohol evaporate (1-2 minutes) and wipe the area with a dry microfiber.
6. If there is any contamination, repeat the procedure or use compressed air (hold the balloon vertically, at a distance of 5-10 cm).

Warning: Do not use abrasive materials (such as paper wipes), water or household chemicals.

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After cleaning the sensor, be sure to restart the smartphone. Sometimes the sensor starts working correctly only after a full on/off cycle.

Hardware malfunctions: when without service can not do

If none of the software methods worked, the problem could be a physical breakdown of the sensor or its plume.

• 🚨 The sensor does not respond at all (even after resetting and calibration).
• 🔌 The screen flashes or spontaneously goes out for no reason.
• 💥 The problem appeared after a fall, moisture or disassembly of the smartphone.

In such cases, you'll need a professional diagnosis.

1.A check of the sensor plume

If you were disassembling the Poco M3 or dropping it, the sensor plume could have moved away from the board.

• 🛠️ Carefully remove the back cover (need a mediator and hair dryer to soften the glue).
• 🔍 Find the proximity sensor plume (usually it goes from the top of the screen to the motherboard).
• 🔌 Check if it's tightly connected. If it's not, gently plug it back in.

⚠️ Warning: Disassembly of the smartphone is no guarantee! M3 For more guarantees, contact the Xiaomi service center - self-repair can cancel it.

Replacement of the proximity sensor

If the sensor is physically damaged (e.g., the glass is cracked over it or the contacts are torn off), it will have to be replaced. The cost of a spare part for the Poco M3 is from 300 to 800 rubles, depending on the region. Self-replacement is possible, but requires experience with a soldering iron and small parts.

Replacement algorithm:

1. Buy the original sensor (article for Poco M3 – check the model of the motherboard).
2. Disconnect the battery (required!).
3. Remove the screen (heating and special suction cups will be required).
4. Unplug the old sensor and install a new one.
5. Put your smartphone back together in reverse order.

FAQ: Frequent questions about the proximity sensor on the Poco M3