Where is the proximity sensor in Xiaomi Redmi Note 9: location, features and diagnostics

The proximity sensor in Xiaomi Redmi Note 9 smartphones is a small but critical component that is responsible for automatically turning off the screen during phone conversations. Its malfunction can lead to accidental tapping of the screen with the cheek, ear or even a complete lack of response to the approach of the face. Many users face the challenge of finding this sensor, especially when it requires cleaning, replacement or diagnosis.

In this article, we will not only show you where exactly the proximity sensor in the Redmi Note 9 is located (including the Note 9 Pro and Note 9S modifications), but also how it works, typical malfunctions and how to check it. You will learn how to distinguish hardware from software failure, and what to do if the sensor ceases to function correctly. For clarity, we have added diagrams, photos and step-by-step instructions - everything that will help you understand the issue without going to the service center.

Where is the proximity sensor in Xiaomi Redmi Note 9: the exact location

In the Xiaomi Redmi Note 9 (model M2003J15SC for the global market), the proximity sensor is integrated into the top of the display module, next to the front camera, specifically located to the right of the speaker, under the screen protective glass. It can not be seen visually with the naked eye — it is hidden under black masking film, but its position is standardized for all devices in the Redmi Note 9 line.

To better understand the location:

• 📱 Top of the screen: The sensor is in the top frame, under a layer of glass.
• 🔍 Near the camera: If you look at the front panel, it is located to the right of the front camera and to the left of the light sensor.
• 📏 Size: The sensor itself is about 2-3 mm in diameter, so it is difficult to see without a magnifying glass.

It's important to understand that the Redmi Note 9 Pro and Note 9S (J2001J15G and M2002J9G models) have the same location, no different layout, and that's because of the unification of the line design. If you're holding the phone in your hands, just swipe your finger across the top bezel to the right of the speaker, and there's a sensor underneath the glass in that place.

How the proximity sensor works: the principle of operation and technical details

The proximity sensor in the Redmi Note 9 is based on infrared radiation, and it consists of two key elements:

1. IR emitter sends a light signal invisible to the human eye.
2. IR receiver – captures a signal reflected from an object (for example, your ear).

When you hold your phone to your ear during a call, the IR beam bounces off the surface and returns to the receiver. The microcontroller analyzes the delay time and signal strength, then sends a command to turn off the screen. This process takes fractions of a second and happens completely automatically. The Redmi Note 9 uses the APDS-9960 model sensor (or its analogue), which is also responsible for the function of gestures in the air (if supported by firmware).

Technical characteristics of the sensor:

Interestingly, the proximity sensor in the Redmi Note 9 can conflict with protective glasses or low-quality films. If the glass is metallized or too thick (more than 0.3 mm), the IR ray will not pass through it, and the sensor will stop working, which is one of the most common causes of false positives.

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If the sensor stopped working after sticking the protective glass, try to make a cut in the area of its location (to the right of the speaker) with scissors or a stationery knife.

How to check the proximity sensor for performance: 3 ways

If the Redmi Note 9 screen doesn't turn off during a call or, conversely, goes out for no reason, the first thing you need to do is check the proximity sensor.

1. Test through the engineering menu (code ##6484##)

The most accurate way is to use a hidden engineering menu:

1. Open the Phone app.
2. Enter the combination ##6484## (some firmware may not work – alternative below).
3. Select the Proximity Sensor.
4. Close the sensor with your finger – the value should change from 5 (no obstacle) to 0 (there is an obstacle).

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

2. Verification through the CPU-Z application

Download the free CPU-Z app from Google Play:

1. Open the Sensors tab.
2. Find the Proximity line.
3. Put your hand to the top of the screen, and the value should change from Far to Near.

3.Manual check during call

The simplest, but less accurate method is:

• 📞 Call another phone or use a voice assistant.
• 🖐️ During the call, cover the top of the screen with your palm.
• 🔍 The screen should go out in 1-2 seconds, and if it doesn't, the sensor doesn't work.

If all tests show a malfunction, the reasons may be as follows:

• 🧹 Sensor contamination (dust, sweat, film glue residue).
• 🛠️ Mechanical damage (a crack in the glass above the sensor).
• 🤖 Software failure (incorrect settings or firmware error).
• 🔌 Disconnection of the plume (after falling or disassembling the phone).

Cleaning the proximity sensor: step-by-step instructions

In 70 percent of cases, the sensor stops working because of the accumulation of dirt or grease on its surface, and you can clean it yourself without disassembling the phone.

• 🧻 Wormless napkin (for example, for glasses).
• 💧 Alcohol wipes or isopropyl alcohol (70%+).
• 🔦 Lantern (for illumination).
• 🧲 Plastic blade (optional if dirt is under glass).

Step-by-step process:

1. Turn off the phone – this will prevent false alarms of the sensor during cleaning.
2. Illuminate the upper frame with a flashlight to see the exact location of the sensor (right of the speaker).
3. Moisten the napkin with alcohol and gently wipe the sensor area in circular movements without pressing.
4. For persistent contaminants, use a plastic spatula to slightly tamper with the edge of the protective glass (only if you are confident in your skills!).
5. Let the phone dry 5-10 minutes before turning on.

⚠️ Warning: Do not use sharp metal objects (knives, needles) - they can damage the anti-reflective coating of the screen or the sensor itself. Also avoid excess liquid: alcohol should not leak under the display frame.

If the sensor doesn't work after cleaning, try resetting your phone to factory settings (Settings → Phone → Settings → Reset) to help eliminate software errors. If that doesn't work, it's probably hardware (requiring a replacement of the sensor or plume).

Typical malfunctions of the proximity sensor and their solutions

Even if the sensor is physically functional, it can be disrupted by external factors, and let's look at some of the most common problems and ways to fix them:

One of the most insidious malfunctions is when the sensor is running in tests but it doesn't work during a call.

• 📱 Application conflict (e.g., conversation recording programs lock the sensor).
• 🔄 A firmware error (especially relevant for custom ROM devices such as LineageOS or Pixel Experience).
• 🔊 Speaker malfunction (if it doesn't work, the phone may "think" the call is not active).

⚠️ Warning: If you are using Xiaomi.eu or other unofficial firmware, check for bugs in the 4PDA forum. Often sensor problems are solved by updating or rolling back to the stable version MIUI.

To diagnose application conflicts, run your phone in Safe Mode (press the power button → long tap on "Stop" → "Safe Mode"). If the sensor is working normally in this mode, delete the newly installed programs one by one until you find the culprit.

Replacement of the proximity sensor: when it is needed and how much it costs

If all the diagnostic and cleaning methods didn't work, the only option is to replace the sensor. In the Redmi Note 9, it's soldered into a flexible plume that also includes the front camera and the light sensor, which means that you can't replace the proximity sensor alone, you have to change the entire module.

Cost of repairs in service centers:

• 🛠️ Official Xiaomi service: 2,500-4000 ₽ (including diagnostics and operation).
• 🔧 Unofficial workshops: 1,500–2,500 ₽ (but the risk of substandard parts is higher).
• 📦 Self-replacement: 800–1,500 ₽ (cost of a plume on AliExpress) + a soldering dryer is required.

The replacement process includes:

1. Disassembly of the phone (removal of the back cover, battery, motherboard).
2. Disconnect the old plume and install a new one.
3. Check the performance of the sensor and camera.
4. Build a phone with a replacement heat paste (recommended).

⚠️ Warning: If you replace yourself, you risk damaging the flexible plumes of the display or battery. If you don't have experience with soldering equipment, you should contact the professionals. Also note that after dismantling, water protection may break (if any).

Where to buy spare parts:

• 🌍 AliExpress is a cheap option, but a long wait (search on request Redmi Note 9 proximity sensor flex cable).
• 🏬 Local parts stores are faster but more expensive (check reviews).
• 🔄 Donor phones – can be found on Avito or in service centers (sometimes sold broken Redmi Note 9s with work plumes).

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Before buying the plume, make sure it is compatible with your Redmi Note 9 modification (check the model on the sticker under the battery).

Frequent questions about the proximity sensor in Xiaomi Redmi Note 9