Owners of Xiaomi budget smartphones often face an annoying problem: during a conversation, the screen goes out and stops responding to touches, preventing you from completing a call or switching to speaker. This situation is especially relevant for the Redmi 9A model, where software failures can misinterpret data from the distance sensor. The user finds himself in a desperate situation when the interlocutor is already talking, and you can’t do anything except wait for the end of the beeps or frantically try to unlock the device with a power button.
The reason is that the approach sensor is too sensitive or sticky, which is located at the top of the case next to the speaker. Unlike flagship models, in the budget segment, the calibration of this module is often not perfect, which leads to false positives even without putting the phone to the ear. Fortunately, the MIUI system allows you to flexibly control this parameter, completely disabling it or reconfiguring the logic of operation through hidden engineering menus.
In this guide, we will look at all the available ways to solve the problem, from standard system settings to the use of specialized utilities. On the Redmi 9A with a MIUI 12 shell and above, there may not be a standard switch on the menu, so you will need to use the codes of engineering mode. It is important to understand that turning off the sensor will deprive you of the function of automatically turning off the screen in the ear, but will return full control of the device during calls.
The reason for the sensor incorrect operation on the Redmi 9A
Before you start taking drastic measures and getting into system settings, you need to understand the nature of the error. The Redmi 9A uses a virtual proximity sensor that works in conjunction with the accelerometer and gyroscope, making it dependent on software calibration algorithms. Often a failure occurs after an operating system update, when new drivers conflict with the old calibration settings recorded in the device memory.
The second common cause is physical contamination of the top of the screen or the use of poor-quality protective glasses. Even a thin film with a black frame can block the infrared emitter, which makes the system “think” that the phone is constantly in the ear. In such cases, software shutting down the sensor becomes the only quick solution, although cleaning the speaker of dust and grease is a more correct approach from a technical point of view.
Also worth noting is the impact of third-party applications that can intercept sensor control. Antiviruses, memory cleaners or call recording applications sometimes block the standard “bell ringer” from accessing hardware modules. If the problem appears suddenly after installing new software, it is worth checking the list of recently installed programs and testing the phone in Safe Mode.
Checking the performance through the engineering menu
The first step before any tampering with settings is diagnostics, and Xiaomi smartphones have a powerful hardware testing tool built in, which is available through special code, so you can make sure that the problem is a software glitch, not a physical module breakdown. To run the test, you need to open the standard Phone app and enter the character combination.
Type ##6484## into the dialing field. The device will automatically go to CIT (Customer Information Test) mode without requiring call confirmation. In the list that opens, find "Proximity Sensor" or "Approximation Sensor." When you click on it, you'll see the current distance in centimeters. Close the top of the screen with your palm, the value should change from "5.0" (or more) to "0.0." If there is a reaction, but the calls fail, you need to recalibrate or shut down.
If the sensor in this menu doesn't respond to hand movements or shows random values, the problem can be hardware. However, even with a proper hardware, a software conflict can block it from working in mode.
Method of disabling through the developer settings
Some versions of the MIUI contain a hidden way to control sensor behavior through a developer menu, which is less risky than using third-party software and does not require root rights. However, it is worth remembering that the set of options available depends on the specific version of Android and the regional firmware installed on your Redmi 9A.
To activate this mode, you need to quickly press the "Version" item seven times. MIUI» And then we go back to the main settings menu, and we go to the "About the phone» → «For developers. You should scroll down to the section that you're looking for for for input or network settings. Look for an option called "Disable proximity sensor" or "Proximity sensor check».
If you find that option, just turn the switchboard to off, which will force the system to stop responding to sensor readings during calls, and the screen will stop going out, but you will have to complete calls yourself with an on-screen button or power button, because holding the phone to your ear will no longer block the display, a compromise solution that returns functionality to the detriment of automation.
Use of specialized fixing applications
The most effective and popular solution for Redmi 9A owners is to install a third-party application that intercepts the sensor, which works in the background and force the sensor value to be “opened” to prevent the system from turning off the screen. One of the most reliable tools is the application “Proximity Sensor Fix” or its counterparts.
Once the application is installed, you need permissions to do so, usually access over other windows and permission to start in the boot, and you need to select your device model or Force Off mode in the program settings. After you have set the settings, the phone may need to restart to take effect.
It's important to note that these applications consume minimal power, but they still work in the background. On the low-end Helio G25 processor installed in the Redmi 9A, unnecessary processes can theoretically affect autonomy, although in practice the effect is almost imperceptible. The main advantage of the method is the ability to quickly turn the sensor back on if you get used to standard behavior or decide to sell the phone.
Comparison of problem-solving methods
The best way to choose depends on your technical literacy and willingness to tolerate certain inconveniences. Each method has its advantages and disadvantages, which are worth weighing before implementing changes to the system. Below is a comparison table to help determine the tactics of action.
| Method | Difficulty | Security | Impact on the battery |
|---|---|---|---|
| Engineering menu | Medium | Tall. | No influence. |
| Fixing annexes | Low. | Medium | Minimum |
| Developer settings | Low. | Tall. | No influence. |
| Resetting calibration | Tall. | Medium | No influence. |
As you can see from the table, using an engineering menu or developer settings is the safest way to do so, without affecting system resources. However, these methods are not always available or effective on specific versions of firmware. Fixing applications, despite the need to install additional software, often become the only working option for Redmi 9 models.
If you're not sure about your abilities, start with the simplest thing: checking for a protective film and cleaning the speaker. Only after making sure the device is clean, move on to software manipulation. Remember that any interference with system settings is at your own risk, although the methods described are widely used by the community and are considered safe.