The problem with the proximity sensor on the smartphones of the line of Redmi is one of the most common complaints of users, especially owners of the Note 9 Pro. The situation when during a telephone conversation the screen does not go out or, conversely, does not light up after the distance of the phone from the ear, causes serious discomfort. This occurs due to software failures, incorrect calibration or physical contamination of the sensor area.
In this article, we will discuss in detail how to turn on the proximity sensor on the Xiaomi Redmi Note 9 Pro, conduct its accurate calibration through the engineering menu and eliminate software conflicts. It is important to understand that modern Xiaomi devices use a virtual sensor that works in conjunction with the accelerometer, so its setting requires a specific approach that is different from the old models with physical sensors.
Before you start complex manipulations, you need to make sure that the problem is software-based, not related to mechanical damage or protective film. Often users inadvertently close the area of operation of the sensor with dense glass, which blocks its operation. We will consider all the stages of diagnosis and adjustment to ensure that your Redmi Note 9 Pro functions correctly.
⚠️ Before making changes to the system settings or engineering menu, make sure the device’s battery is at least 40% in charge to avoid sudden shutdown during the calibration process.
Diagnostics and check of sensor performance
The first step before any setup is to thoroughly diagnose the current state of the system. In the MIUI shell installed on the Redmi Note 9 Pro, there is a built-in tool to check all hardware modules. Run the test to determine whether the system sees the sensor itself and whether it reacts to changes in the environment.
To start the diagnosis, open the Phone app and enter the universal code ##6484##. This action will automatically redirect you to the CIT engineering test menu. In the list that appears, you need to find the item "Proximity sensor" or "Proximity Sensor." Click on it to go to the testing mode.
In the test mode, you'll see numerical values or a color indication. Hold your palm to the top of the screen where the speaker is located, and remove it. If the values change and the color of the indicator switches from red to green (or vice versa), the hardware is good. If there is no reaction, the problem may be drivers or a physical defect.
- 📱 Make sure the protective film does not cover the area above the speaker where the sensor is hidden.
- 🧹 Wipe the top of the screen with a microfiber, removing fat and contaminants that may distort readings.
- 🔄 Restart the device before the test to rule out temporary software crashes.
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If the CIT test sensor shows values, but in life does not work, the problem lies in the software calibration, which we will discuss in the next sections.
Calibration through MIUI Engineering Menu
If the diagnostics show that the sensor is responding but not correctly (e.g., it is turning off the screen too soon or too late), a calibration procedure is required. This is the most effective method for the Redmi Note 9 Pro, which allows you to reset sensitivity thresholds, and the process is performed directly in the testing menu, where we were previously.
If you're in the Proximity Sensor section of the CIT menu, you'll notice the bottom of the screen, and you'll see the Calibration or Calibration button, and you'll click on it, and the system will warn you that it's normal to go out and turn on during the calibration process, and never interrupt until it's done automatically.
During calibration, you may need to close the sensor with your hand and then open it by following the prompts on the screen. Once the procedure is complete, the device will give a message "Proximity sensor calibration successfully" or similar. Be sure to reboot the smartphone so that the new settings take effect.
☑️ Checklist of correct calibration
It's worth noting that in some versions of MIUI firmware, the calibration button may be hidden or inactive, in which case the system relies on automatic calibration each time it's turned on, and if the automation fails, reset the sensor settings through the developer menu, but this requires more care.
Setup through the developer menu
To get a deeper setup, including sensor behavior control, you need to activate a hidden developer menu. This is a standard procedure for Android devices to access advanced features. On the Xiaomi Redmi Note 9 Pro, this menu also contains options that affect the operation of the sensors.
To activate the developer mode, go to Settings → About the phone. Find the line "Version." MIUI» And press it fast. 7-10 Once you've become a developer, you can go to the settings. → Advanced settings → For developers.
Inside the developer menu, scroll down to the section that's associated with input data or touch screens. We're interested in the Quick Start Sensor option or similar variations that depend on the Android version. And here you can find debugging settings that sometimes help reset the suspended sensor services.
ADB's Hidden Teams
Be careful when changing the parameters in this section. Incorrect changes can lead to unstable operation of the system as a whole. If you are not sure about the purpose of a particular parameter, it is better to leave it unchanged or pre-write the original value.
| Parameter | Default value | Recommended action | Impact on the sensor |
|---|---|---|---|
| Quick start | Included. | Change | Accelerates sensor response |
| Sensor test | Off. | Used for diagnostics | Starting the test mode |
| Pointer location | Off. | Turn it off. | Displays touch tracks (does not affect) |
| Strict mode | Off. | Turn it off. | Screen blinking during long operations |
Use of third-party applications for calibration
In cases where the built-in MIUI tools don’t help solve the proximity sensor problem on the Redmi Note 9 Pro, specialized applications from the Google Play Store come to the rescue. These utilities have more flexible calibration algorithms and can force the sensor configuration files to be overwritten.
One of the most popular and proven solutions is the Proximity Sensor Reset & Test app. Once installed, launch the program and provide the necessary permissions. Press the Calibrate button and follow the instructions on the screen. The app will ask you to close the sensor and then open it several times to collect data.
Another efficient option is Sensor Calibration, which allows you to calibrate not only the proximity sensor, but also the accelerometer, gyroscope and compass. Complex calibration often gives the best result, because the virtual distance sensor depends on the location of the phone in space.
- 📲 Download apps only from verified sources (Google Play).
- 🚫 Avoid apps with questionable permissions that require access to contacts or SMS.
- 🔄 After using third-party software, be sure to perform a full reboot of the device.
⚠️ Note: Third-party apps may ask permission to “paint over other windows” for their work, but make sure you trust the developer as this is a high level of access.
Impact of system updates and resetting settings
Often, problems with the proximity sensor occur after the MIUI operating system update. New firmware versions may contain bugs or change the logic of the drivers. If the problem occurs immediately after the update, it makes sense to wait for the patch to come out or try to reset the system settings.
Resetting to factory settings is a radical but effective method. Before you do that, make sure to back up all the important data, as all the information will be deleted. Go to Settings → About Phone → Reset → Clear all the data. This will put the software back in a state close to factory.
Even if a full reset didn’t help, the problem may be hardware or incompatibility of a particular firmware version with your device instance, and users often resort to flashing the device to a global or custom version of the software, but this requires deep technical knowledge.
It is important to note that in some regions, the Redmi Note 9 Pro firmware has software limitations or sensor features, and checking the XDA developer forum for your particular model can give you information about known bugs of the current version of the software.
Hardware causes and physical maintenance
And the physical causes of the malfunction are not to be discounted. In the Redmi Note 9 Pro, the proximity sensor is located in a narrow strip above the screen. Any contamination, moisture or mechanical damage to this area can lead to failure. Even a thin layer of fat from the fingers can block the infrared radiation from the sensor.
If you've used a safety glass, make sure it has a special cutout or a transparent area above the sensor. Cheap glass can have a black frame that covers the sensor, even if it's not visually noticeable. Take the glass off and check the sensor's performance without it.
If moisture gets inside the case (for example, after rain or falling into the water), the sensor may temporarily not work. Put the phone in a dry place, you can use silica gel, but do not use a hair dryer or heating appliances, as this can damage the glue that holds the display.
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If software methods and cleaning did not help, and the phone fell or got wet, there is a high probability of physical damage to the plume or the sensor itself, requiring repair in the service.
In rare cases, the plume that connects the control board to the sensor module departs. This can happen after a strong impact. Self-disassembly of the Redmi Note 9 Pro is difficult due to the glass back cover and many screws, so it is better to trust this procedure to professionals.