Approximation Sensor in Xiaomi Redmi 9T: where is it and how to check it

Xiaomi Redmi 9T is a popular budget smartphone, but even in such models sometimes have problems with sensors. One of the frequent malfunctions is the failure of the proximity sensor, which does not go out during the call or, conversely, turns off for no reason. If you encounter such a problem, the first thing you need to do is find and check the sensor.

In this article, we will go into detail about where the proximity sensor in the Redmi 9T is located, how it looks on the board and on the display, and give instructions on diagnosis and possible repairs, you will learn whether you can replace the sensor yourself, what tools you will need, and what to do if the problem is not in it, but in the software.

The material will be useful for both beginners who want to understand the device of their smartphone, and those who are planning self-repair, all recommendations are based on official Xiaomi schemes and the experience of service centers.

What is a proximity sensor and why it is needed in a smartphone

The proximity sensor is a small electronic component that detects how close an object is to the screen (usually your ear when you call) and its primary function is to turn off the touch screen when you hold the phone to your head to avoid accidental tapping.

The Redmi 9T uses an infrared proximity sensor, which consists of two parts:

• 🔦 The emitter sends an invisible infrared signal.
• 👁️ Receiver – captures the reflected signal and determines the distance to the object.

If the sensor fails, the following problems arise:

• 📵 The screen does not go out during the call (risk of accidental pressing).
• 🔄 The screen spontaneously turns off even without a call.
• 🔋 Fast battery discharge (sensor is constantly running in the background).

In most cases, the malfunction is due to contamination of the sensor (dust, fat), damage to the plume or software failure, less often - with physical failure of the sensor itself.

Where is the proximity sensor on Xiaomi Redmi 9T: external location

In the Redmi 9T, the proximity sensor is located at the top of the screen, next to the front camera and speaker, and the exact location can be determined by a small round or oval hole under the display glass.

To find it visually:

1. Turn on the flashlight and shine on the top of the screen at an angle – the sensor will look like a tiny black dot.
2. Or run a sensor test (we will talk about it below) – a hint will appear on the screen.

The photo below shows the exact location (marked with a red circle):

Searchable reference points:

• 📱 Right of the front camera (when looking at the screen).
• 🔊 Left of the conversational dynamics.
• 🕳️ Under glass – looks like a small dark hole (diameter) ~1 mm).

⚠️ Warning: Don't confuse the proximity sensor with the light sensor! The latter is usually located to the left of the front camera and is responsible for automatically adjusting the brightness of the screen. 9T These sensors are separated, but are close by.

What does the proximity sensor look like on the Redmi 9T board

If you're disassembling a phone for repair, the proximity sensor on the Redmi 9T motherboard is a little black chip marked, and it's connected to the board through a flexible plume that comes from the display module.

The main characteristics of the sensor in this model:

• 📏 Size: ~2×2 mm.
• 🔧 Type: Infrared (IR).
• 🔌 Connection: Through the display plume (not a separate connector!).

In the photo of the board, the sensor is usually marked as PROXIMITY or PS (from English proximity sensor). If you are looking for a replacement, note that in the Redmi 9T it is soldered into a display module - you can not buy it separately, only together with the screen.

⚠️ Warning: When disassembling the phone, don't pull the sensor plume, it's very fragile! Damage to the plume will cause the sensor to be completely inoperable, and you'll have to change it with the display.

How to check the proximity sensor on the Redmi 9T

Before you disassemble the phone, make sure that the sensor is the problem. There are several ways to do this:

Method 1: Testing through the Engineering Menu

The most reliable method is to use a hidden engineering menu:

1. Open the Phone app.
2. Enter the code: ##6484## (or #4636## → Equipment Testing).
3. Select the Proximity Sensor.
4. Put your hand to the top of the screen, and the value should change from 5 (far) to 0 (close).

Method 2: Checking through applications

If the engineering menu is not available, install one of these apps:

• 📱 Phone Doctor Plus (checks all sensors).
• 🔍 Sensor Test (represents data in real time).
• 🛠️ CPU-Z (It shows the presence of a sensor in the system).

Method 3: Visual Testing

Simple test without software:

1. Call another phone.
2. Hold the Redmi 9T to your ear, and the screen should go out.
3. Take the phone away, the screen should turn back on.

If the screen does not respond, the sensor is defective or contaminated.

1. Check the operation of the sensor through the engineering menu

2. Clean the top of the screen of dirt and dust

3.Reboot your phone (sometimes helps with software failures)

4. Update the firmware to the latest version-->

Why the proximity sensor may not work: the main reasons

If tests show that the sensor is not responding, the reasons may be as follows:

Pollution is the most common problem, and dust, sweat, or cosmetics can block the infrared signal, and less often, mechanical damage occurs after a phone falls or disassembles.

In 80% of cases, the proximity sensor malfunction in Redmi 9T is due to contamination or software failure, not a physical breakdown.

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If the sensor stopped working after the screen was replaced, it is likely that the wizard damaged the plume or improperly connected the display module.

How to fix the proximity sensor on Redmi 9T yourself

If you're sure the sensor is the problem, not the software, you can try fixing it yourself.

1. Sensor cleaning

This will require:

• 🧴 Isopropyl alcohol (70% or higher).
• 🧻 Soft lilac-free fabric (microfibra).
• 🔦 Lighting lamp.

Instructions:

1. Turn off the phone.
2. Wet the fabric with alcohol and gently wipe the top of the screen (especially near the front camera).
3. Bring a flashlight - the sensor should be clean, without stains.
4. Let the phone dry 5-10 minutes before turning on.

2. Reboot and reset settings

If the sensor is glitching due to a software failure:

• 🔄 Restart your phone (hold the power button for 10 seconds).
• 📱 Reset the settings to factory (Settings) → The phone. → Resetting settings).
• 🔧 Update the firmware to the latest version (Settings) → Updating the system).

Replacement of the display module

If the sensor is physically damaged, it can't be replaced separately, just with the screen.

1. Buy the original display module for Redmi 9T (article: MDY10-0001-00 or similar).
2. Disassemble the phone by disconnecting the battery and plumes.
3. Replace the module and reassemble the phone.

⚠️ Warning: Replacing the screen takes experience!If you've never repaired phones, it's best to contact the service - build errors can damage other components.

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In 90 percent of cases, the problem is solved by cleaning the sensor or resetting the settings, and changing the screen is a last resort if other methods have not worked.

Frequent errors in the repair of the proximity sensor

Many users make mistakes that only make the problem worse.

• 🚫 Use sharp objects to clean the sensor (you can scratch the glass or damage the sensor).
• 🚫 Blowing the sensor with compressed air - this can drive the dust deeper.
• 🚫 Disassemble the phone without turning off the battery - the risk of short circuit.
• 🚫 Install non-original spare parts - they may not match the connectors.

Also common is that the sensor is not built correctly after the screen is replaced, for example, if you forget to plug in the sensor plume or squeeze it when you build it, the sensor will not work even if it is functional.

If you have a problem after repairing yourself, you should contact the service center. Xiaomi has official partner workshops, where repairs will cost less than buying a new phone.

FAQ: Frequent questions about the proximity sensor in the Redmi 9T