The proximity sensor in Xiaomi Redmi 9C NFC smartphones is a small but critical component that is responsible for turning off the screen during a phone conversation. If it fails, users will face accidental taps on the screen with the cheek, ear or shoulder, which leads to malfunctioning of the phone. However, many owners of this budget device do not know exactly where this sensor is located and how to diagnose it.
In this article, we will look at the exact location of the proximity sensor on the Redmi 9C NFC, explain how it works in tandem with other sensors, and provide step-by-step instructions to check it, and learn what signs indicate a sensor malfunction and whether it can be repaired yourself, and the material will be useful for both beginners and experienced users who want to understand the hardware of their smartphone.
What is a proximity sensor and why you need it in the Redmi 9C NFC
The proximity sensor is an infrared sensor that detects an obstacle (such as an ear or hand) near the top of the screen, and its main task is to automatically turn off the touch screen and backlight during a phone conversation to avoid accidental taps. In the Xiaomi Redmi 9C NFC, this sensor is integrated into the top of the display and works in tandem with MIUI software.
Without a proper proximity sensor, users are faced with:
- 📱 Self-enabled hands-free or other functions during a call;
- 🔄 Uncontrolled scrolling of pages or pressing buttons;
- 🔋 Fast battery discharge due to constant screen operation;
- 📞 Interrupting calls when touching the screen with the cheek.
In the Redmi 9C NFC, the proximity sensor is combined with a light sensor that regulates the brightness of the screen, both of which are in the same module, but they have different functions, and if one of them fails, it can affect the work of the other.
Where exactly is the proximity sensor on Xiaomi Redmi 9C NFC
In the Xiaomi Redmi 9C NFC, the proximity sensor is located at the top of the screen, to the left of the speaker. If you look at the front panel of the smartphone, the sensor is under the black frame of the display, next to the front camera. The exact location can be determined by a small circular hole (about 2 mm in diameter), covered by a protective mesh.
Visually, the proximity sensor in the Redmi 9C NFC looks like this:
- 📍 To the left of the speaker (when looking at the screen);
- 🔴 Under a black frame, next to the front camera;
- 🕳️ It is a small hole with a transparent or dark coating;
- 📱 On some devices it may be marked with a dot marking.
For clarity, the following is a diagram of the location of the sensors on the front panel of the Redmi 9C NFC:
| Component | Location. | Function |
|---|---|---|
| Approximation sensor | Left of the speaker speaker | Turns off the screen during the call |
| Light sensor. | Near the proximity sensor | Adjusts the brightness of the screen |
| Front camera. | Centered to the upper frame | Selfies and video calls |
| Speaking speaker | Right of the sensors. | Transmission of the voice of the interlocutor |
If you're disassembling a smartphone, the proximity sensor is attached to a flexible display plume and connected to the motherboard via a connector, which you can only see after you take off the screen, so you'd better use software methods for diagnostics (which we'll talk about later).
What does the proximity sensor look like in a disassembled phone?
How to check the proximity sensor on the Redmi 9C NFC
Before you take the phone apart, you should make sure that the proximity sensor is the problem, and you can use built-in MIUI tools or third-party apps to do that.
- Testing through the Engineering Menu: Enter the Phone app code ##6484##. The sensor test menu will open. Select Proximity Sensor and hold your hand to the top of the screen. If the sensor is working, the screen should go out, and when you remove your hand, it should light up again.
- Check through Sensor Test: Download the Sensor Test app from Google Play (e.g. from Smart Tools developer) and run the proximity sensor test and observe the reaction to the obstacle.
- Visual test during a call: Call someone (or use hands-free mode) and cover the top of the screen with your hand. The screen should go out. If that doesn't happen, the sensor is faulty.
If the sensor does not respond to any of the actions, the problem may be:
- 🛠️ Sensor pollution (dust, fat, protective film);
- 🔌 Damage to the display plume;
- 📱 Software failure (reset or flashing required);
- 💥 Physical breakdown of the sensor (replacement required).
Make sure there is no protective film or glass on the screen.|
Clean the top of the screen from dust and dirt |
Check the sensor in the engineering menu |
Install a sensor testing app (e.g., Sensor Test)-->
Causes of malfunction of the proximity sensor and methods of elimination
The proximity sensor in the Redmi 9C NFC can fail for several reasons, and let's look at the most common ones and how to fix them:
| Cause of malfunction | Signs. | Decision |
|---|---|---|
| Sensor contamination | The screen does not turn off or is triggered with a delay. | Clean the upper frame with alcohol and soft fabric |
| Damage to the display plume | Sensor does not respond at all, artifacts on the screen are possible | Replacement of a plume or display module |
| Firmware failure | The sensor is unstable, problems appeared after the update | Resetting settings or flashing through Fastboot |
| Physical sensor breakdown | Complete lack of reaction, possible damage after falling | Replacement of the sensor or display module |
If the sensor stopped working after a phone drop or moisture, most likely, you will need to disassemble the device, in this case, we recommend contacting the service center, as self-repair can damage other components.
⚠️ Note: When disassembling Redmi 9C NFC Be careful with the flexible plume of the display, which is very fragile. Damage to the plume can disable not only the proximity sensor, but also the touch screen.
How to repair the proximity sensor (step-by-step instructions)
If you're confident in your skills and willing to take risks, you can try to fix the proximity sensor yourself.
- 🔧 Set of screwdrivers (cross, flat, tweezers);
- 🧴 Isopropyl alcohol (90%+);
- 🧻 A hairless napkin;
- 🔥 Fryer (for softening glue).
Step-by-step process:
- Turn off the phone and remove it. SIM-map.
- Heat the screen edge with a hair dryer (~60°C) to soften the glue.
- Carefully tuck the screen with a plastic spatula, starting at the bottom edge.
- Disconnect the display plume from the motherboard (pay attention to the lock!).
- Clean the proximity sensor with alcohol and a napkin, and if it's damaged, replace it with a new one.
- Collect the phone in reverse order, making sure the plume is tightly connected.
If the sensor doesn't work after assembly, it might be the firmware problem, and then resetting to factory settings or flashing through Fastboot will help.
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Before disassembling the smartphone, take a picture of the location of all the plumes and screws - this will help to properly assemble the device back.
Frequent errors in the repair of the proximity sensor
Many users, when trying to fix the proximity sensor on the Redmi 9C NFC, make critical errors that only exacerbate the problem.
- 🔧 Using metal tools to tweak the screen - this leads to scratches and damage to plumes.
- 🔥 Overheating by a hair dryer – high temperature can melt glue or damage the display.
- 💧 Getting liquid on the motherboard during cleaning the sensor.
- 📱 Incorrect connection of the plume after assembly, which leads to a broken screen.
- 🔌 Ignoring checking software settings before disassembly.
To avoid these mistakes, follow the instructions and take your time. If you have never disassembled smartphones, it is better to contact professionals - the cost of repairing the proximity sensor in the service center usually does not exceed 1000-1500 rubles.
⚠️ Warning: If after self-repair the phone stopped turning on or the screen does not respond to touch, immediately take it to the service. Attempts to "fix" the device without experience can lead to complete failure of the motherboard.
Alternative ways to solve the problem with the proximity sensor
If the proximity sensor on the Redmi 9C NFC does not work, but you do not want to disassemble the phone, you can use alternative methods:
- 📱 Disabling the sensor in settings: Go to Settings → Special facilities → The proximity sensor and turn it off, but it will keep the screen running continuously during calls.
- 🔄 Headphone use: When talking through the headset, the proximity sensor is not used, which excludes accidental pressing.
- 🔧 Installing third-party software: Apps like Proximity Sensor Fix can emulate sensor performance, but this is a temporary solution.
- 📲 Resetting to factory settings: Sometimes software failures are solved by a complete reset (be sure to back up your backup!).
These methods will not replace full-fledged repair, but will help temporarily solve the problem if the sensor is out of order, and the possibility to take the phone to the service is not.
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Turning off the proximity sensor in the settings is an extreme measure, as it reduces the usability of the phone during calls.