How to fix a malfunctioning proximity sensor on Xiaomi: from calibration to repair

The proximity sensor in Xiaomi smartphones is a small but critical element that is responsible for turning off the screen during a phone call. When it fails, you face annoying problems: the screen does not go out when you approach the ear, accidentally press buttons during a call, or vice versa, the display does not turn on after the call is completed. In 80% of cases, the fault can be fixed by yourself without the help of a service center.

In this article, we’ll look at all possible causes of failure, from software failures to physical damage, and provide step-by-step diagnostic and repair instructions. You’ll learn how to check the sensor’s performance through an engineering menu, calibrate it manually, clean it from contamination, and even replace the sensor if needed. The focus is on the Redmi Note 10/11/12, POCO X3/X4, and Mi 11/12, but the methods will be suitable for most of the brand’s devices.

Before we start repairing, it's important to understand that the proximity sensor is not just an eye next to the front camera, it's a complex of infrared emitters and photodetectors that analyze the reflected signal, and if any of the elements fail, the whole system stops working correctly, which is why the diagnostics must be comprehensive.

1.How to check the proximity sensor on Xiaomi: 3 ways to diagnose

Before you try to fix the sensor, make sure it's the problem, and users often confuse the sensor malfunction with MIUI software bugs or mechanical damage to the screen, and here are three reliable ways to check:

Method 1: Testing through the Engineering Menu

1. Open the Phone app and type ##6484## (for some models, #4636##).
2. Select Hardware Testing → Sensor → Proximity Sensor.
3. Put your hand to the top of the screen (where the front camera is located), and the sensor will show a value of 0 (obstacle detected) or 1 (no obstruction).

Method 2: Checking through the CPU-Z application

• 📱 Install CPU-Z from Google Play and go to the Sensors tab.
• 👆 Cover the sensor with your hand – the Proximity value should change from 5.0 cm to 0.0 cm.
• 🔍 If the readings are unchanged or Unsupported is displayed, the sensor is faulty.

Method 3: Visual inspection

Take a flashlight and shine it on the top of the screen next to the front camera, and when you're working, you'll see a faint red or purple glow -- that's the infrared emitter of the sensor, and if there's no glow, the problem could be a cliff of contacts or a chip damage.

⚠️ Warning: On Xiaomi 12T and Redmi Note 12 Pro+ models, the proximity sensor is integrated into the display module. If the sensor does not respond during the test, but there is a glow, the plume or screen controller may malfunction.

2. Software methods of correction: calibration and resetting of settings

In 60 percent of cases, the proximity sensor stops working because of a software failure, which can happen after a MIUI update, custom firmware installation, or even because of an application conflict, starting with the simplest ways to do this.

Calibration of the sensor through a hidden menu

Many Xiaomi models allow you to manually calibrate the sensor.

1. Please type in the phone keyboard ##6484##.
2. Select Proximity Sensor Calibration (Sensor Test → Proximity on some firmware).
3. Follow the instructions on the screen: usually hold and remove your hand from the sensor 3-5 times.
4. After calibration, restart the device.

Resetting sensor settings

If the calibration didn’t help, try resetting all sensor settings:

• 🔧 Go to Settings. → The phone. → All specifications.
• 👆 Tap the kernel (or MIUI version 5 times) to activate the developer mode.
• 🔄 Back to Settings → Additionally. → For developers and find Sensor Reset.

Updating or rolling back firmware

Bugs in the MIUI often cause sensor malfunction. Check for updates in Settings → System Update. If the problem occurred after the last update, try to roll back to the previous version using the Mi Flash Tool (instructions for power users).

Make a backup copy of the data

Record the phone's IMEI

Check the battery (minimum 50%)

Install the official firmware from the Xiaomi website-->

⚠️ Warning: The POCO F3 and Redmi K40 models, after upgrading to MIUI 14, have massive complaints about a failed proximity sensor, the solution being a rollback to MIUI 13.0.6 or waiting for a patch from Xiaomi.

3. Cleaning the proximity sensor: remove dirt and dust

One of the most common causes of malfunction is contamination of the infrared emitter, and dust, potassium fat deposits, or residues of protective film can block the signal, and cleaning takes 5 minutes and often solves the problem.

What you need:

• 🧴 Alcohol wipes (70-90%) or cotton swabs dipped in alcohol.
• 🔦 Loupe or flashlight for accurate cleaning.
• 🧲 Plastic blade (to remove glass, if required).

Step-by-step:

1. Turn off the phone and take off the case.
2. Find the sensor – it is located to the right or left of the front camera (on some models under the glass).
3. Gently wipe the area with a napkin, paying attention to the cracks around the camera.
4. For deep cleaning, use a cotton swab dipped in alcohol, but without pressing.
5. Let the phone dry for 10-15 minutes before turning on.

If the sensor is located under glass (as in Xiaomi 13 Pro), it may be necessary to remove the protective glass.

1. Heat the glass with a hair dryer (temperature not higher than 60 ° C).
2. Tap the edge with a plastic spatula and carefully remove.
3. Clean the sensor and install new glass (or use old if it's whole).

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Do not use abrasive materials (such as toothpaste) to clean the glass, and damage the sensor even more, and an ultrasonic bath (if you have experience with it) will do the job.

4. Replacement of the proximity sensor: when without repairs can not do

If the software and cleaning didn't work, it's probably physically damaged, and if you do, you'll need to replace it, and the cost of a new sensor is 300 to 1,500 rubles depending on the model, and let's take two options: replace it yourself and in the service center.

Self-replacement: step-by-step guide

You will need to work:

• 🔧 Set of screwdrivers (cross, flat, tweezers).
• 🔥 A dryer or thermo-air station for screen removal.
• 🛠 New proximity sensor (buy with the phone model!)
• 🧲 Suction cups for display removal.

Instructions:

1. Turn off the phone and remove the back cover (heating the edge hairdryer).
2. Disconnect the battery to avoid short circuit.
3. Remove the display module, gently disconnecting the plumes.
4. Find the proximity sensor – it is located on a flexible board next to the front camera.
5. Unpold the old sensor and install a new one (use a soldering station with a thin sting).
6. Put the phone back together.

Replacement at the service center: what you need to know

If you're not sure about your skills, it's best to turn to professionals.The average cost of replacing the proximity sensor in services:

⚠️ Warning: On models with AMOLED- screens (e.g., Xiaomi 12S Ultra), the proximity sensor is often integrated into the display module, in which case it will cost 5,000–8,000 rubles to replace the screen completely.

5. Alternative solutions: how to use a phone without a sensor

If repairs are delayed and the sensor is not working, you can temporarily adapt the phone to your needs.

5.1. Disconnect the sensor in the settings

In some MIUI firmware there is an option to force the sensor to turn off:

1. Go to Settings → Special Options → Physical buttons.
2. Find the item Disable the proximity sensor (or Ignore the sensor during the call).
3. Activate the option and restart the phone.

The downside: the screen will not go out during calls, so you will have to manually block it with the power button.

Use of sensor emulation applications

Applications like Proximity Sensor Fix and Sensor Disabler allow you to:

• 📱 Forced to extinguish the screen when approaching (timer).
• 🔕 Turn off the sensor during calls.
• 📊 View the sensor log in real time.

Please note that these programs require ADB or root rights, which may violate the warranty.

Customization of gestures

On models with MIUI 12+, you can set a gesture to lock the screen during the call:

1. Go to Settings → Gestures → Gestures during the call.
2. Activate the option of Double-Tap to lock.
3. Now, during a conversation, it is enough to touch the screen twice to turn it off.

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If the sensor is physically functional but not working because of firmware, try installing custom software (like LineageOS or Pixel Experience).

6. Frequent errors in the repair of the proximity sensor

Many users compound the problem by trying to fix the sensor in the wrong way, and here are the most common errors and their consequences:

Use of non-original spare parts

Buying cheap Chinese analogues instead of the original Xiaomi sensors leads to:

• 🔴 Sensor malfunction (false positives).
• 🔥 Overheating due to incompatibility with motherboard.
• 📉 Quick failure (service life 1-3 months).

How to avoid: Buy parts only from trusted suppliers (such as AliExpress Official Store or Mi Store) and check items.

Improper handling of plumes

When disassembling the phone, it's easy to damage the flexible plumes that connect the sensor to the motherboard.

• 🔌 Contact break (results in complete sensor inoperability).
• 🔥 Short circuit (may disable the power controller).
• 📱 Loss of sensitivity (the sensor only works when approached strongly).

Tip: Use plastic blades and do not apply force when disconnecting the plumes.

Neglect of inspection after repair

After replacing the sensor, it is necessary to:

1. Take the test through the engineering menu (#6484##).
2. Call your phone and check if the screen is going off.
3. Make sure there are no false positives (such as in your pocket).

If the sensor is not working properly, it may be curved or recalibrated.

FAQ: Answers to Frequent Questions