Approximate sensor on Xiaomi Redmi 9T: Where to find out how to check and fix problems

The proximity sensor in Xiaomi smartphones is a small but critical element responsible for turning off the screen during a conversation. 9T (codenamed lime, this sensor often becomes a source of problems: the screen does not go out when you lift it to the ear, random pressing during calls, or, conversely, a “dead” panel that does not respond to touch. In 80% of cases, the proximity sensor is to blame – either its contamination or hardware failure.

Find this sensor on Redmi 9T Unlike flagship models, where the sensor is placed on the front panel next to the speaker, in budget Redmis it is often hidden under the glass or integrated into other modules. This article will help to accurately determine its location, check the operability without disassembling the phone and understand when to contact the service center.

What is a proximity sensor and how does it work in Redmi 9T

The proximity sensor is an infrared sensor that detects the distance between the screen and an object (like your ear). 9T it is used for:

• 📞 Turn off the screen during a call (saves charge and prevents accidental taps).
• 🔄 Automatic display when removing the phone from the ear.
• 🛡️ Protection against false positives of touch screen (for example, when the phone is in your pocket).

At Redmi. 9T It uses an optical sensor (not a capacitive sensor like the old ones) and it has two elements:

1. Infrared emitter (LED), light-emitting.
2. A photodiode that picks up the reflected signal, and if the object is close, the light comes back, the sensor goes off.

It's important to understand that the proximity sensor is not the same as the light sensor (which regulates the brightness of the screen). 9T They're located nearby, but they have different functions. If the screen doesn't go out during the call, but the brightness is automatically adjusted, the problem is the proximity sensor.

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If the light sensor is working (the brightness of the screen varies depending on the light) and the proximity sensor is not, then the problem is definitely not the firmware or the drivers. It is either a hardware malfunction or a contamination of the sensor.

Where exactly is the proximity sensor on Xiaomi Redmi 9T

At Xiaomi Redmi. 9T The proximity sensor is located at the top of the front panel, but its exact position depends on the modification of the phone:

To determine exactly where the sensor is on your Redmi 9T, Follow the following steps:

1. Turn on the flashlight on the other phone.
2. Bring it to the top of the Redmi screen 9T (wherein).
3. If the sensor is separate, you will see two small circular holes (one emits infrared light, the other receives).
4. If you can't see the holes, it means the sensor is hidden under the speaker grille.

Some Redmis. 9T (Especially in the Indian and Chinese versions, the sensor can be integrated into the display module, in which case it cannot be seen from the outside, and the diagnostic software will be required.

Signs of malfunction of the proximity sensor

If the proximity sensor is on Redmi 9T It is not working properly, you will notice the following symptoms:

• 📵 The screen does not go out when you bring the phone to your ear during a ringing (the most common problem).
• 🔦 The screen does not turn on after the conversation is over (you have to press the power button).
• 👆 Accidental taps during a call (nose or ear touches the touchscreen).
• 🔄 Spontaneous on/off screen when blocking.
• 📱 The “lift to wake up” gesture does not work (if it is tied to the sensor).

Sometimes the problem lies not in the sensor itself, but in:

• 🧹 Sensor contamination (dust, sweat, remnants of protective film).
• 🔧 Damage to the plume after falling or disassembling the phone.
• 🖥️ Firmware failure (especially after update) MIUI).
• 🔋 Battery malfunction (at low charge, sensors can turn off).

Before you carry your phone for repair, try to diagnose the sensor yourself, and 60 percent of the time, it's solved by cleaning or resetting the settings.

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If the screen doesn't go out only in certain apps (like WhatsApp or Telegram), the problem isn't with the sensor, it's with the settings of those programs. Check the permissions and the call settings.

How to check the proximity sensor on Xiaomi Redmi 9T pieceless

There are several ways to test the proximity sensor without disassembling the phone, and let's start with the simplest test, the built-in test. MIUI.

Method 1: Built-in test MIUI (code ##6484##)

This is the hidden diagnostic menu that is on all Xiaomi smartphones:

1. Open the Phone app.
2. Enter the combination: ##6484## (or #4636## → Equipment Testing).
3. Select Proximity Sensor (Proximity Sensor).
4. Put your hand up to the top of the screen, and if the sensor is working, you'll see a change from 5 (far) to 0 (close).

If the values do not change or show N/A, sensor is faulty or disabled at the firmware level.

Method 2: Checking through the Engineering Menu

More advanced diagnosis is available through the engineering menu:

1. Enter the code on your phone: ##4636##.
2. Go to the Hardware Testing → Sensors section.
3. Find the Proximity Sensor line.
4. Cover the sensor with your hand – the value should change from Far to Near.

If the sensor doesn’t respond, try cleaning it (more on that below) or resetting it.

Method 3: Verification with third-party applications

If the built-in tests don’t work, install one of these apps:

• 📱 CPU-Z (Sensors section – shows the status of all sensors.
• 🔍 Sensor Test – Specialized Sensor Tester.
• 📊 Phone Doctor Plus – Checks the performance of all modules of the phone.

If the applications show that the sensor is not available, this may mean:

• 🔌 Firmware error (you need to reflash the phone).
• 🛠️ Hardware failure (pipe break or sensor failure).

Built-in test tested MIUI|The dirt sensor cleared|Third-party applications tested|Resetting to factory settings is performed|Update checked MIUI-->

How to Clean Up the Approach Sensor on Redmi 9T

In 40 percent of cases, the sensor stops working because of pollution, and the dust, the sweat, the glue residue from the protective film or the glass, they block the infrared signal, and it takes 5 minutes to clean up, and often solves the problem.

What you need:

• 🧴 Alcohol wipes (or cotton swab) + isopropyl alcohol 70%+).
• 🕯️ Toothpick or plastic card (for careful removal of dirt).
• 🔦 Flashlight (to better see sensor holes).

Step-by-step:

1. Turn off your phone to avoid accidental tapping.
2. Hold the flashlight to the top of the screen and find the sensor holes (or speaker grille if the sensor is hidden underneath).
3. Soak the cotton swab in alcohol and gently wipe the sensor area. Don't press hard!
4. If the dirt is clogged deep, use a toothpick wrapped with a wet napkin.
5. Let the phone dry 5-10 minutes before turning on.

⚠️ Warning: Do not use sharp objects (needles, knives) - they can damage the protective glass of the sensor.

After cleaning, re-check the sensor using one of the methods described above. If the problem persists, proceed to the next step.

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If the sensor is hidden under the speaker grille, cleaning becomes more complicated, in which case you can try to blow the hole with compressed air (for example, a canister to clean the keyboard), but do not direct the jet too close.

Software solutions to the problem

If the sensor is physically healthy but not working, the problem may be in firmware or settings. MIUI. Here's what we can do:

1. Resetting sensor settings

Sometimes it helps to reset the calibration of sensors:

1. Go to Settings. → The phone.
2. Click on Version. MIUI 7-10 times to activate the developer mode.
3. Back to Settings → Additionally. → For developers.
4. Find the item Reset sensors and confirm the action.

2.Update MIUI

In some versions MIUI (especially 12.0-12.5) were sensor bugs:

1. Open Settings → Update the system.
2. Click Check for updates.
3. If a new version is available, install it.

3. Retrace to factory settings

If the problem occurs after the update, try resetting your phone:

1. Make a backup copy of the data.
2. Go to Settings → About the phone → Reset settings.
3. Choose to erase all data.

⚠️ Note: After the reset, all data will be deleted, including photos, contacts and apps. If the phone is not synced with Mi Account, it will be impossible to restore the information.

Manual switching on of the sensor (for advanced users)

If the sensor is disabled at the system level, it can be activated via ADB:

adb shell settings put system proximity_sensor_enabled 1

For this:

1. Install ADB on your computer.
2. Get Redmi on board. 9T down USB with debugging enabled (Settings) → For developers → Debugging by USB).
3. Run the command above at the terminal.

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If the sensor doesn't work after all the manipulations, it's a hardware problem, and if you do that, you can just replace the module or the plume at the service center.

When is the time to bring your phone to service?

If none of these methods worked, it's probably a hardware problem, and here are some signs you should call in the experts.

• 🔧 The sensor does not respond to any tests (including the engineering menu).
• 💥 The phone fell or got wet before the problem appeared.
• 🔌 The screen flashes or spontaneously turns off for no reason.
• 🛠️ Visible damage to the sensor area (cracks, dents).

Cost of repairing the proximity sensor on Redmi 9T:

⚠️ Note: If you are offered to replace the entire display module due to a faulty sensor, ask first to check the possibility of replacing only the sensor. In some services, the entire screen is changed, although the problem is solved by replacing a small part for 500 rubles.

Also make sure the service uses original parts. on Redmi 9T Often put unoriginal sensors that work incorrectly or quickly fail.

FAQ: Frequent questions about the proximity sensor on Xiaomi Redmi 9T