Where is the proximity sensor on Xiaomi Redmi 9 NFC: location, inspection and repair

The proximity sensor in Xiaomi Redmi 9 NFC is a small but critical element that automatically shuts down the screen during a phone call. If it fails, you risk accidentally pressing buttons with your cheek or ear, interrupting calls and facing other troubles. However, many users do not even know where this sensor is located in their device — and in vain, because its location directly affects diagnostics and repairs.

In this article, we will not only show the exact location of the proximity sensor on the Redmi 9 NFC (with photos and diagrams), but also analyze the typical signs of its malfunction, ways to check without disassembling the phone, and give practical tips for eliminating problems.

Xiaomi Redmi 9 NFC design: where the proximity sensor is hidden

Unlike Xiaomi’s flagship models, where sensors are often integrated into a display module, the Redmi 9 NFC uses a classic layout. The proximity sensor here is a miniature infrared sensor that picks up a reflected signal from an object (like your ear) and tells the system to turn off the backlight. But where exactly do you look?

In the Redmi 9 NFC, the proximity sensor is located at the top of the front panel, to the right of the speaker, or rather, under a black strip (called a monobrav), which hides the front camera and sensors.

• 📍 Left to right: second element after front camera (first - light sensor).
• 🔍 Visually: small circular hole with diameter ~1mm, disguised as black plastic.
• 🛠️ Disassembly: soldered to the plume of the display module, next to the flexible cable of the front camera.

It's important to understand that the Redmi 9 NFC doesn't have a proximity sensor that's compatible with the light sensor (unlike some Redmi Note models), so they're checked and replaced separately. If you see twotiny holes next to you, the first one (closer to the camera) is the lighting, the second one is the proximity.

What the proximity sensor looks like: photos and diagrams

To avoid confusing the proximity sensor with other elements, we will give its visual differences. The photo below shows the top of the Redmi 9 NFC with the designation:

On a PCB, the proximity sensor is a small black chip marked (usually starting with APDS or STK-). The Redmi 9 NFC uses the APDS-9960 model, a combined sensor that is also responsible for gestures (such as swiping the screen with a swipe of a hand).

Signs of malfunction of the proximity sensor

If the proximity sensor starts to fail, it's very noticeable. Here are the typical symptoms for the Redmi 9 NFC:

• 📵 The screen doesn’t go out when you call, even if you put your phone to your ear.
• 🔦 The backlight spontaneously turns off in normal mode (for example, when reading messages).
• 🎧 The sound switches to the speaker when you hold the phone to your ear.
• 🔄 Sensitivity floats: it works, then it doesn’t (especially after falls or moisture).

Interestingly, in the Redmi 9 NFC, the proximity sensor can also affect the "Rise to Wake Up" function, so if the sensor gives false signals, the phone can wake up in your pocket or, conversely, not respond to your actions.

⚠️ Note: If the screen does not go out only in certain applications (for example, WhatsApp or Telegram), the problem is more likely to be the settings of these programs, rather than the sensor. → Annexes.

Another nuance: in Redmi 9 NFC, the proximity sensor is associated with the Android proximity service. If it does not work correctly, errors such as ProximitySensor: error reading data can appear in the system logs (Settings → About Phone → MIUI Version → 5 times on the “Keronel”).

How to check the proximity sensor without disassembling the phone

Before you bring your phone to the service, try to diagnose the problem yourself. Redmi 9 NFC has several ways to check:

Method 1: Test mode MIUI

1. Open the Phone app and type the combination: ##6484## (or #4636## → "Equipment Testing").

2. Select Proximity Sensor.

3. Cover the sensor with your hand - the value should change from 5.0 cm (no obstacle) to 0.0 cm (obstacle detected).

Method 2: Diagnostic applications

Install one of the apps from Google Play:

• 📱 CPU-Z (Sensors" tab")
• 🔧 Phone Doctor Plus
• 🛠️ Sensor Test (from Innovative Apps)

In these programs, the proximity sensor is displayed as Proximity or APDS-9960. Check the response to the approach of the hand - the graph should change dramatically.

Check the reaction in test mode MIUI|Install an app for sensor test|Wipe the sensor area from dust and dirt|Try restarting your phone.|Reset sensor settings in Settings → Special facilities-->

If the sensor does not respond at all, the reasons may be as follows:

• 🧹 Pollution: Dust or fat blocks infrared signal.
• 💧 Moisture intake: oxidation of contacts on the plume.
• 🔌 Bad contact: the sensor plume has moved away from the board.
• 💥 Mechanical damage: crack in sensor after falling.

⚠️ Attention: Redmi 9 NFC Approximate sensor may temporarily "glue" after update MIUI. If the problem appeared after the update, try to roll back to the previous version of the firmware or reset the settings through Settings. → System system → Resetting settings (select "Resetting app settings").

What to do if the proximity sensor is not working

If the diagnosis confirmed the malfunction, act on the algorithm:

1. Clean the sensor, wipe the area around the sensor with a cotton swab dipped in alcohol, don't use sharp objects, you risk damaging the sensor!
2. If the phone fell, the plume of the display module (the solder sensor) may have gone, and then you need to disassemble and solder.
3. Calibration. In some cases, calibration through the engineering menu helps: ##284### → Proximity Sensor → Calibrate
4. Sensor replacement: If the sensor is physically damaged, it will need to be replaced. In the Redmi 9 NFC, the sensor is assembled with a front camera plume (~500-800 rubles on AliExpress).

To replace the sensor, you will need:

• 🔧 Set of screwdrivers (cross, flat, tweezers).
• 🔥 A dryer or a station for heating the glue (display glued).
• 📦 New sensor or plume (article: Xiaomi Redmi 9) NFC Proximity Sensor Flex Cable).
• 🧲 Magnetic screw mat (so as not to lose small details).

💡

Before the Redmi 9 disassembly NFC definitely take out SIM-In this model, the card tray is located next to the battery, and if you move carelessly, you can damage the contacts.

If you are not sure about your skills, you should contact the service. The cost of replacing the proximity sensor in the Redmi 9 NFC in official Xiaomi centers is ~ 1,200-1,800 rubles (taking into account work). Informal workshops can make it cheaper, but the risk of poor repairs is higher.

Differences between the proximity sensor in the Redmi 9 NFC from other Xiaomi models

In the Redmi and POCO lineup, the proximity sensor location can be very different.

Redmi 9. NFC The proximity sensor is not compatible with the display, which makes it easier to replace it. AMOLED-The sensor is often soldered into the display module, and its replacement requires a complete replacement of the screen.

Another difference is firmware. In Redmi 9 NFC, the sensor is controlled by the apds9960.ko driver, which sometimes conflicts with custom firmware (like LineageOS).

1. Install the original driver from stock MIUI.
2. Reverse the kernel to a version compatible with the sensor.
3. Manually prescribe the sensor parameters in the file /vendor/build.prop.

Frequent questions about the proximity sensor in the Redmi 9 NFC

💡

In 90% of cases, the proximity sensor malfunction in Redmi 9 NFC is not due to the sensor itself, but to pollution, poor plume contact or software failure. Before you spend money on a replacement, be sure to diagnose the instructions above!