Disconnect and configure the proximity sensor on Xiaomi Redmi 9

Xiaomi Redmi 9 smartphones are equipped with modern sensors that should ensure comfortable use of the device, but in practice, users often face incorrect operation of the approach module: the situation when during a conversation the screen goes out and stops responding to touch, or, conversely, does not turn off when the phone is pressed to the ear, is familiar to many owners of budget models. The proximity sensor on Redmi 9 is often located under the screen, making it sensitive to protective glasses, dust or software failures of the MIUI operating system.

Complete software shutdown of this sensor in the standard Android settings menu is not provided by developers for security and ergonomics reasons, as this can lead to accidental cheek pressing during a call. However, there are proven methods of circumventing restrictions, including the use of an engineering menu, third-party calibration applications or installing specialized utilities that block the sensor at the software level. In this article, we will discuss all the available ways to solve the problem, from simple settings to more complex manipulations.

Before taking drastic measures, it is important to understand the nature of the malfunction, since in most cases, the Redmi 9 does not require a complete shutdown, but a correct calibration. Sensor malfunction can be caused by a glued protective glass that covers an invisible zone at the top of the display, or a buildup of dirt in the speaker. It is critical to first eliminate physical factors and perform a standard calibration through an engineering menu before using third-party locking software.

The reason for the incorrect operation of the sensor on the Redmi 9

The main reason for the sensor problems on the Xiaomi Redmi 9 is its location under the display. Unlike the older models, where the sensor was placed in a separate window next to the speaker, here it reads data through the screen layer. This makes the device vulnerable to the quality of protective films and glasses: even a microscopic gap or air bubble at the top can distort the readings, making the system think that the phone is near the ear.

The second common cause is software conflicts of the MIUI shell. After updating the system or installing "heavy" design themes, errors may occur in the operation of the drivers responsible for processing sensor signals. System failure can cause calibration data to be lost or replaced by incorrect default values, in which case the screen may go out arbitrarily or, conversely, burn constantly.

Physical pollution is also important, because a speaker grid that's right next to the sensor area gets clogged with dust, skin fat and pile from your pocket over time, and this creates an additional barrier to infrared radiation that uses the sensor to determine the distance to the object, and cleaning that area with an alcohol napkin or a soft brush often solves the problem without having to go into the settings.

⚠️ Note: Use of poor-quality protective glasses with a black frame covering the top of the screen is the most common cause of sensor failure on Redmi 9. If after removing the glass the problem disappeared, further software adjustment is not required.

Finally, you can't rule out hardware failure of the module itself or the plume connecting it to the motherboard, and if the phone fell or was exposed to moisture, the contacts could oxidize or move away, in which case the software methods would be useless, and you would need to interfere with the hardware of the device in the service center.

Standard calibration through the engineering menu

The safest and most effective way to solve the problem is to recalibrate the sensor through the built-in Xiaomi engineering menu, which does not require root rights and allows you to reset the sensor settings to factory values, given the current conditions (the presence of protective glass, cover).

Type ##6484## into the dial box. If the code is entered correctly, the system will automatically redirect you to the CIT menu. This is a list of all components of the smartphone. You need to find the item associated with the proximity sensor. On different versions of the firmware, it can be called "Proximity sensor", "Proximation sensor" or have a number, for example, "15" or "23".

Once you enter the test, you'll see two values: "Raw Data" (current reading) and "Max/Min" (borders). Put your phone on a flat surface and do not cover the top of the screen with anything - the value of "Raw Data" should be 0.0 or close to zero. Then close the upper third of the screen (the speaker area) tightly with your palm. The value should change to 5.0 or another maximum number. If changes occur, press the Calibrate or Pass button to save the results.

In some cases, after calibration, you need to reboot the device to apply new parameters. If the CIT menu is successful (values change correctly), but the problem persists in life, then it is not a calibration, but a software conflict or physical obstacle, then you can move to more complex methods, including the use of third-party software.

Using applications to lock the sensor

If the calibration didn't work, and you want to completely ignore the sensor readings when you call, the easiest solution is to install a specialized application from Google Play, which doesn't physically turn off the sensor, but intercepts its signals and prevents the system from extinguishing the screen when the proximity data arrives, which allows you to control the screen while you're talking without removing the phone from your ear.

One of the most popular and proven solutions is the Proximity Sensor Reset & Fix app, or the equivalent of the Near Proximity app, and once installed, you'll need to give the app the permissions you need, including the right to draw over other windows and access system settings, without which it won't be able to take control of the screen.

• 📱 Proximity OFF — simple application with one function: turn on or off the sensor lock through the widget on the desktop.
• 🛠️ Sensor Box for Android is a powerful diagnostic tool that also allows you to emulate the operation of the sensor and reset its cache.
• 🔧 Fix It! is a utility that automatically tries to fix driver errors and offers a “Force Off” mode for the sensor.

⚠️ Note: When using locker apps, the phone screen will burn constantly during the call.This can lead to occasional cheek presses, so be careful and adjust the touchscreen sensitivity if such an option is available.

Once the app is installed, you usually need to start it, press the activation button and, in some cases, restart the smartphone. For the Redmi 9 with its capacious battery, this will not become critical, but it is better not to limit background activity in the MIUI energy saving settings.

Developer settings and system parameters

In the Android operating system, including the shell MIUI redmi-based 9, It's hidden in a developer menu that contains parameters that affect sensor behavior, and although there's no direct "Disable Sensor" button, you can change the behavior of the system when you lock it, or you can run diagnostics that sometimes reset the got stuck driver. To enter the developer menu, go to Settings → On the phone and press quickly 7-10 once by “Version” MIUI».

Once activated, a new “Advanced” or “Advanced Settings” section will appear in the settings menu, where you can select “Developers For.” Scroll down to “Input” or “Multimedia.” There may be a “Quick Sensor Switch” or similar option, but it depends on the Android version and the specific firmware build. On Redmi 9 with Android 10/11, these hidden switches are rare, but it’s worth checking.

Also on the developer menu, it's helpful to reset the debugging settings. Find the USB debugging option and make sure it's off if you're not using it all the time. Sometimes the debugging enabled can conflict with the system sensors. You can also try resetting the network and Bluetooth settings, as they sometimes affect the overall stability of the communication modules and sensors.

If you don't find the right settings, don't experiment with unknown developer menu items. Changing the rendering or processor settings can cause the entire system to run in an unstable way. The main purpose of using this section is to reset software errors, not directly control the hardware.

Solving problems with protective glasses and covers

As mentioned earlier, the Xiaomi Redmi 9's design with a subscreen sensor makes the device extremely sensitive to accessories. Many users buy cheap black-framed protective glass that is Designed to hide the screen frames, but in the case of the Redmi 9, it often blocks the sensor's operation. Even if the glass is transparent in the center, the adhesive layer at the edges can create an optical effect that knocks the sensor down.

To check if the glass is causing the problem, do a simple test: during an incoming call, when the screen is out, try swiping your finger not in the center, but at the top, above the speaker, or slightly shift the phone from the ear. If the screen lights up or the reaction appears when you shift, then the sensitivity zone is closed, in which case only replacing the accessory with a notch under the sensor or without a black bezel will help.

Cases can also be a source of problems, especially thick silicone or metal bumpers.If the side of the case comes onto the screen or creates a shadow over the sensor, the system will receive false signals. Metal cases can shield the signal or cause interference. It is recommended to use thin cases specially designed for the Redmi 9, which have accurate cutouts.

In situations where glass replacement is impossible and the problem is annoying, you can try to programmatically increase the sensitivity threshold if the calibrator app allows it. Some utilities allow you to set a dead zone or change the reaction algorithm, which helps offset the effect of a thick protective coating.

Resetting and radical measures

When neither calibration, nor apps, nor replacement of accessories help, the last software method is a complete factory reset.This action will delete all your data, applications and photos, so make sure to back up in the Mi Cloud cloud or on your computer before the procedure.Reset will return all system drivers and configuration files to their original state, eliminating possible deep software conflicts.

To perform the reset, go to Settings → About Phone → Settings Reset → Erase all data. The device will reboot and start a cleaning process that can take 10 to 30 minutes. Once turned on, the phone will be like new. If even in this state, without installed applications and with a clean screen, the sensor is not working correctly, the probability of hardware failure is up to 90%.

⚠️ Warning: Complete data reset is an irreversible procedure. Make sure you remember the password from your Mi Account and Google account, otherwise the phone may be locked after the reset due to theft protection (FRP).

If the problem persists after the reset, it is a hardware defect, which can be a retiring plume (which happens after falls) or the sensor itself fails, in which case the software methods are powerless, and the only solution is to go to an authorized service center to replace the module or solder the sensor.

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If the complete reset and replacement of the protective glass did not help, the problem is hardware, and software cannot solve it.

Frequently Asked Questions (FAQ)

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When buying a new protective glass for Redmi 9, look for the option marked "Case Friendly" or "For the proximity sensor", or choose glass without a black bezels at the edges.