How to check the proximity sensor on Xiaomi Redmi 9T

Redmi series smartphones have earned a reputation for reliability, but even time-tested models such as Xiaomi Redmi 9T sometimes experience specific hardware failures. One of the most common and annoying problems is the incorrect operation of the proximity sensor, which is responsible for turning off the display during a conversation. Users often face a situation where the screen goes out immediately after you put the phone to your ear or, conversely, does not respond at all, leading to accidental cheek presses.

Before you take your device to a service center or try to reset completely, you need to make an accurate diagnosis of the current state of the module, which will allow you to understand whether the problem is a software error, contamination or physical damage to the component. In this article, we will discuss in detail all the available ways to check the functionality of the sensor on the Redmi 9T, using both built-in system tools and hidden engineering menus.

Proper diagnosis will save time and money, and will provide insight into whether the issue can be solved by software calibration or require intervention in the hardware. We will look at the steps that every owner should follow when noticing strange behavior of the screen during calls, and offer specific solutions to fix the malfunction.

Symptoms of proximity sensor failure

You can tell that your Xiaomi Redmi 9T has a proximity sensor problem by a number of features that are predominantly present during voice communication. The main indicator is the behavior of the screen: when it is in good condition, it should go out when you bring the phone to your ear, and light up again when you remove the device. If the screen continues to burn while the phone is near your ear, you will inevitably encounter blind presses.

Sometimes the problem is reversed: the display goes off immediately after the call begins, before you even hold the phone to your head, which makes it impossible to use hands-free or view contact information during a conversation, and you should also pay attention to the work of applications using this sensor, such as some games or video players, which can block control when you close the top of the screen with your finger.

It is important to distinguish between a software glitch and a physical malfunction: If the problem occurs in only one particular application or after a system update, it is likely to be the software, but if symptoms are persistent and in all use cases, the likelihood of hardware malfunction increases.

• 📱 The screen does not go out when you bring the phone to your ear during a ringing.
• 🌑 The display turns off immediately after the call starts without reacting to the device position.
• ✋ Accidental tapping of the cheek or ear interrupts conversation or involves holding.
• 🔦 Notification indicator or flash may flash strangely when the screen is locked.

⚠️ Attention: If the screen goes out in your pocket without a call, it may cause the battery to run out or occasional emergency calls».

Using the CIT Engineering Menu for Diagnostics

The most reliable way to test the performance of hardware modules on the Xiaomi Redmi 9T is to use an integrated engineering menu known as the Calibration Information Test (CIT), which is a hidden part of the system designed for technicians and allows you to test each component of the device separately, including sensors, screen, microphones and communication modules. Access to it does not require root rights, but requires accurate command input.

To start the diagnosis, you need to open the standard application "Phone" and dial a special one. USSD-On the devices. MIUI This is usually a sequence of characters that automatically redirects the user to the service menu. Once you log in, you'll see a list of all the tests available where we're interested in the item associated with the Proximity Sensor.

Inside the test, the system will ask you to close the top of the screen (where the speaker and sensor are located) with your palm. If you work correctly, the Value values should change from 5.0 to 0.0 (or vice versa, depending on the firmware version), and the color of the indicator will change from red to green, which confirms that the physical sensor is responding to the obstacle.

If the engineering menu is successful (green), but the problems persist in life, it means that it is a matter of software settings or application conflict, and if the CIT test shows an error or does not respond to hand movements, the problem lies in the module itself or its plume.

Checking through the hidden Android menu

An alternative method that may be available on some versions of the Redmi 9T MIUI firmware is to use the standard Android testing menu.This method is less informative than CIT, but sometimes helps to quickly verify the presence of a signal from the sensor.

Once you enter the command, you will see a list of tests where you want to select the Proximity Sensor. Unlike the Xiaomi engineering menu, it can display a graph or numerical values in real time. The normal indicator for an open sensor is 5.0, and for a closed sensor it is 0.0. Any intermediate values can indicate contamination or calibration.

It is worth noting that on newer versions of Android and MIUI, access to this menu may be restricted by the manufacturer for security reasons. If the code does not work, you should not try to download third-party applications to access hidden features, as this can disrupt the system.

Table of sensor codes and values

For ease of diagnosis, we have collected the basic codes and values that you can encounter during the Xiaomi Redmi 9T verification process. Understanding these parameters will help you interpret the test results correctly and avoid false conclusions about the device breakdown.

The sensor values may vary depending on the calibration, but the logic of changing them remains the same: the presence of an obstacle should radically change the readings. If the values float without touching the screen, this is a sign of interference or malfunction.

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Abrupt switching of values from 5.0 to 0.0 is considered normal. A smooth change or delay in reaction indicates a problem.

Calibration of the proximity sensor on the Redmi 9T

If the diagnostics show that the sensor is responding but is not doing it correctly (e.g., extinguishing the screen too soon or too late), calibration may be required. On Xiaomi devices, this process is often automated, but in some cases requires manual resetting of the calibration procedure, especially after replacing the glass, screen or protective film.

To perform calibration, the CIT engineering menu usually has a separate button or item that allows you to reset your current sensor settings and write down new ones. Before starting the procedure, make sure that the top of the Redmi 9T screen is completely clean and there are no foreign objects on it, including your finger.

Once you start calibrating, the system will ask you to remove your hand from the screen and then close the sensor. It is important to do this clearly and quickly, without delaying in intermediate positions. Successful calibration is confirmed by the corresponding message on the menu.

• 🧹 Wash the top of the screen with microfiber before starting.
• 🚫 Remove the protective film if it closes the speaker area.
• 📱 Calibrate at the brightness of the screen near 50-70%.
• 🔄 Restart the device immediately after the procedure is completed.

⚠️ Note: Do not calibrate in bright direct sunlight, as the sun’s infrared radiation may distort the sensor readings.

Programmatic causes of failures and their elimination

It’s not always the hardware that’s the problem. Quite often on the Xiaomi Redmi 9T, proximity sensor failures are caused by software conflicts or settings on the MIUI system itself. One common cause is Pocket Mode, which uses the proximity sensor to prevent accidental taps in your pocket. If this feature doesn’t work properly, it can lock the screen at inappropriate times.

Also worth checking for system updates. Xiaomi regularly releases patches that fix sensor errors. Go to the settings and check the relevance of the MIUI version. In addition, some third-party applications, especially those that manage calls or screen, can intercept the control of the sensor.

In rare cases, resetting to factory settings helps, but this method should be resorted to only after eliminating all other options.Be sure to back up important data before reset, since all information from the device will be deleted.

If you've recently installed an app that works with a screen or calls, try removing it and checking the sensor again, often with memory cleaners or gesture control apps being the culprits.

Physical damage and repair of the module

In a situation where software methods and calibration did not help, and tests in the engineering menu show no reaction, there is likely a physical malfunction. In the Redmi 9T, the proximity sensor is integrated into the display plume or located in a separate module at the top of the housing, falls, moisture or simply wear can cause it to fail.

Often, the safety glass becomes a problem. If it's not glued properly or it's thickened in the speaker area, it can block the infrared beam, in which case even a good sensor can't work properly. Try to carefully remove the film or glass and check without them.

If it's the module itself, it's going to require disassembly. Self-repair is possible, but it requires tools and skills, because the Xiaomi Redmi 9T has a back cover glued to the glue and requires careful opening. Replacing the sensor is usually easy for an experienced craftsman, but you can damage the plumes at home.

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When changing the screen, always check for a rubber gasket on the proximity sensor, and its absence will lead to illumination and incorrect operation of the sensor.

The cost of repairs is usually low unless you need to replace the entire display module, but if the device is warranty, the intervention will deprive you of warranty service.

Frequently Asked Questions (FAQ)