How to check the proximity sensor on Xiaomi Redmi Note 8T: from the code *#*#6484#*#*** to calibration

The Xiaomi Redmi Note 8T is a popular smartphone with a robust hardware platform, but even it can have problems with the proximity sensor over time. This little sensor is responsible for turning off the screen during a conversation, preventing accidental cheekstrokes. If the screen does not go out when you call or, conversely, does not turn on after the conversation is most likely the sensor is to blame. In 80% of cases, the problem is solved software, but you need to accurately diagnose the malfunction.

In this article, we will understand 5 working methods of checking the proximity sensor on the Redmi Note 8T — From standard engineering codes to specialized applications, you'll learn how to tell hardware failure from software failure when you need to calibrate and when you need to replace a module. MIUI 12-14 no-demand ROOT-rights (except for one exception).

What is the proximity sensor and how it works in the Redmi Note 8T

The proximity sensor in the Xiaomi Redmi Note 8T is an infrared sensor located at the top of the screen next to the speaker.

• 🔦 Infrared emitter sends an invisible beam;
• 📡 Photodetector - captures the reflected signal.

When you hold the phone to your ear, the beam bounces off the surface and comes back, and the sensor picks up that and tells the system to turn off the screen. When you pull the phone, the signal disappears, the screen turns on again. The Redmi Note 8T uses a model sensor, STK3311 (or similar), which is integrated into the general module with the light sensor.

Signs of sensor malfunction:

• 📵 The screen does not go out during the ringing (even if the ear is tightly pressed);
• 🔄 The screen will not turn on after the conversation is over;
• 🔄 Spontaneous on/off screen when blocking;
• 📱 In games or applications, the screen goes out for no reason (false positives).

⚠️ Warning: If the sensor stops working after a phone drops or moisture hits, the problem is almost always hardware.

Method 1: Check through the engineering menu (#6484##)

The fastest way to diagnose is to use a hidden engineering menu, which is available on all Xiaomi smartphones without any additional apps.

1. Open the phone application;
2. Enter the code ##6484##
3. Select Proximity Sensor (approximation sensor).
4. Press Start Test.

In normal condition, when closing the sensor with a hand (or a sheet of paper), the value should change with the 5 (no impediment to 0 (if the values do not change or show N/A — sensor malfunction.

On some Redmi Note 8T firmware, the engineering menu may be blocked, in which case use the alternative code ##4636##, then go to Hardware Testing → Sensors → Proximity Sensor.

Method 2: Diagnostics via Sensor Test (without ROOT)

If the engineering menu is unavailable or shows incorrect data, install a third-party app. One of the best is the Sensor Test from Innovative Apps (available on Google Play), which tests all the sensors of the smartphone, including approximations, and shows a graph of changes in real time.

How to use:

1. Download and install the Sensor Test.
2. Open the application and find the Proximity tab;
3. Close the sensor with your hand – the value should change from Far (far) to Near (close);
4. Remove your hand, the value should return to Far.

If the values are unchanged or the graph shows chaotic jumps, the sensor is faulty. In the Redmi Note 8T, the normal response distance is 1-3 cm. If the sensor responds only to touch (not to approach) - calibration is required.

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Before testing, remove the protective glass or film from the top of the screen – they can block the infrared signal.

Method 3: Checking through ADB (for advanced users)

If standard methods fail, you can read the raw sensor data through the Android Debug Bridge (ADB), which requires a computer and minimal command line knowledge, but provides the most accurate data.

Instructions:

1. Turn on Developer Mode on your phone: go to Settings → About Phone → MIUI version and press 7 times;
2. Return to Settings → Additional → For developers and enable USB debugging;
3. Connect your phone to your PC and open the command line (or Terminal on Mac/Linux).
4. Enter the command: adb shell dumpsys sensorservice
5. Find the proximity bar in the output and check the values with the closed/open sensor.

Example of correct inference:

mProximitySensor:




handle=5 name="proximity" vendor="STMicroelectronics"




version=1 type=8 maxRange=5.0 resolution=5.0




minDelay=10000 currentValue=5.0

Here, current Value=5.0 means there are no obstacles. When you close the sensor, the value should change to 0.0.

⚠️ Attention: If in conclusion ADB The sensor is missing or shows null, this can mean both hardware malfunction and lock at the firmware level (for example, after an unofficial ROM).

Method 4: Calibration of the proximity sensor (if it is not working correctly)

Sometimes the sensor works, but it's too early, or it's too late, and calibration will help, and on the Redmi Note 8T, you can do it in two ways:

Method 1: Through the Engineering Menu

1. Open the engineering menu with code ##6484##.
2. Choose Proximity Sensor → Calibration;
3. Follow the instructions on the screen (usually close the sensor with a black surface for 3-5 seconds).

Method 2: Sensor Calibration (requires ROOT)

If standard calibration doesn't work, use Google Play's Sensor Calibration app, which allows you to manually set trigger thresholds. On the Redmi Note 8T, the optimal values for the STK3311 sensor are: minimum threshold 0, maximum threshold 5, hysteresis 1.

After calibration, restart the phone and check the sensor during the call. If the problem persists, it may be a sensor contamination or mechanical damage.

Method 5: Visual inspection and cleaning of the sensor

Often, the proximity sensor stops working because of accumulated dirt or damage to the infrared filter. On the Redmi Note 8T, it is located to the right of the speaker (if you look at the screen).

• 🔍 Take a magnifying glass and a flashlight;
• 🧴 Gently wipe the sensor area with a cotton swab soaked in alcohol;
• 🚫 Do not use sharp objects – it can damage the IR filter;
• 🔄 After cleaning, check the sensor through the engineering menu.

If you see cracks or chips on the sensor, you will need to replace the module. In Xiaomi service centers, the cost of replacing the proximity sensor for the Redmi Note 8T It is 1,200-1,800 ₽ (2026).

Frequent Mistakes and How to Avoid Them

When diagnosing a proximity sensor, users often make mistakes that distort the results.

• 📱 Testing through glass or film – the infrared signal is blocked even by a thin protective glass;
• ☀️ Direct sunlight - can knock down the readings of the photodetector;
• 🔋 Low battery power – at levels below 15%, the system can ignore sensor signals;
• 🛠️ Using metal objects for testing – they reflect IR rays differently than skin.

Another common mistake is trying to calibrate the sensor without first cleaning it, because the dust and fat on the sensor distort the readings, and calibration will only make the problem worse. Always start with a visual inspection!

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If the proximity sensor on the Redmi Note 8T stopped working after the MIUI update, try rolling back to the previous firmware version. Some builds (such as MIUI 13.0.4) had bugs with sensor drivers.

FAQ: Answers to Frequent Questions