How to Find and Check the Approximation Sensor on Xiaomi: The Complete Guide

Xiaomi, Redmi and Poco smartphone owners often face a situation where the screen does not go out during a conversation, and the interlocutor accidentally presses the control buttons with his cheek. This problem is directly related to the operation of the proximity sensor. It is easy to find it physically on the device body, but for diagnosis and calibration, you need access to hidden system tools that are not visible on the regular menu.

In modern models, this sensor is often hidden under a protective glass or integrated into the case, making it impossible to visually detect without disassembling. However, software methods allow not only to “find” it in the system, but also to check the health and sensitivity. Understanding where to look for this component in the program code and engineering menus is key to solving most screen problems.

Next, we will discuss in detail all the available ways to activate the test mode, place the sensor in different series of devices and methods for eliminating software failures. You will learn how to use the hidden capabilities of the MIUI and HyperOS shell to accurately diagnose the hardware of your gadget without going to the service center.

Physical location of the sensor in different models

Before we jump into software tests, it's important to understand exactly where the touch module is located in your particular device. In older models like the Redmi Note 8 or Mi 9T, the sensor was often placed in the top bezel above the display and was visible as a small black dot next to the speaker, which made it easier to check: just tape the top of the screen to see the system's reaction.

With the advance of technology and the desire for bezel-less design, manufacturers have moved the sensor under the display or integrated it into the structure of the screen itself. In models like the Xiaomi 13 or Poco F5, it is physically impossible to “find” it with its eyes. It is hidden under the matrix layer, and it requires full palm cover of the top of the screen, not a point exposure.

⚠️ Warning: Do not try to find the sensor by disassembling the phone or removing the protective film unless you have the appropriate experience. In models with a subscreen sensor, mechanical impact on the top of the display can lead to broken pixels.

In some budget series, such as the Redmi A lineup or the old Poco C, manufacturers sometimes use a virtual sensor based on algorithms for analyzing video stream from the front camera if a physical infrared module is missing.

Using the CIT Engineering Menu for Diagnostics

The most reliable way to find and test a proximity sensor on Xiaomi is by using the built-in CIT (Customer Integration Test) engineering menu, a tool designed to factory-check all components of the device and available on most of the brand’s smartphones.

To get to the menu, open the standard application “Phone” and enter a special USSD-On shell devices. MIUI This is usually a combination of ##6484##. If the code doesn't work, try ##4636##, which leads to the common Android testing menu. Once you enter the code, the menu will open automatically, without having to press the call button.

In the list that opens, you'll find a item that might be called "Proximity Sensor," "Proximity Sensor," or simply "Proximity." You click on it, you'll be in testing mode. Here the screen usually turns black or white, and the system reads the sensor readings in real time. Put your palm to the top of the phone, and the values should change (usually from 5.0 to 0.0 or vice versa, depending on the software version).

If the CIT menu values do not change when you close the sensor with your hand, this may indicate a software driver failure or a physical component failure, in some cases, multiple closure and opening of the sensor (simulated conversation), which allows the system to recalibrate the threshold values.

Secret Codes and Hidden Android Settings

In addition to the standard CIT menu, there are alternative codes for accessing advanced sensor information, which are useful if the standard test does not show detailed data, or if the CIT interface is trimmed by the manufacturer. One of these codes is ##7780##, which opens the reset menu, but can also contain information about the state of the system.

For a deeper analysis, you can use debugging codes that output statistics across all sensors. Type ##426## (Google Play Services) or #8255# (GTalk Service Monitor), although they are often blocked on newer versions of Android. More relevant is the #0# code that works on many devices with MediaTek chips and some Snapdragon, opening the Quick Testing Hardware dashboard.

In this case, you can try changing the region in the phone settings to India or Singapore, which sometimes unlocks additional features of the service, but for work with sensors, a standard CIT is often enough.

Using third-party apps from the Play Market, such as “Phone Tester” or “Sensor Test,” is a great alternative if the system codes don’t work.These apps request direct access to the Android sensor API and show real-time graphs of value change, which is sometimes even more convenient than the dry digits of the engineering menu.

Calibration of the sensor through the engineering menu

If the sensor is found but is not working properly (the screen goes out too early or doesn't go out at all), it needs calibration. This is the process of setting thresholds at which the system thinks the object is nearby. At Xiaomi, this procedure is often done automatically, but in the CIT menu there is the option of manually starting.

The Proximity Sensor test menu often features a Calibrate button or data reset option. The process usually looks like this: you take your hand away from the screen, press the calibration button, wait for a few seconds, then close the sensor and wait again. The system remembers the minimum and maximum light/reflection value.

For Qualcomm-based devices, there is a hidden engineering menu available through ##3646633# (MediaTek) or similar variations for Snapdragon. There, in the Hardware Testing -> Sensor -> PS (Proximity Sensor), you can find the PS Calibration option. Pressing the Do Calibration button will trigger the automatic setup process.

⚠️ Attention: When calibrating, make sure that there is no protective film on the screen with a cutout in the middle covering the sensor.

Program conflicts and MIUI settings

Often the problem lies not in the hardware, but in the software conflicts of the MIUI shell or HyperOS. The system can block access to the sensor to save energy or due to an error in the operation of a particular application (for example, a messenger or a third-party call).

Go to Settings -> Lock and Protect -> Mode in your pocket. Make sure the switch is active. If it is off, the screen may not lock when you bring it to your ear, as the system ignores sensor signals for charge saving or because of a bug. It's also worth checking the permissions for the Phone application: Settings -> Applications -> Application Management -> Phone -> Permissions.

Third-party calling apps like Google Phone or Truecaller can have their own approach sensor processing settings. Inside the app settings, there's often a "Draw-up Sensor" option that can be forced on or off, and if the standard call is working fine and the third-party call isn't, the problem is the cache or settings of that particular app.

💡

If the sensor stopped working after the MIUI update, try clearing the Phone and Xiaomi Services cache through the application management menu, which solves 80% of software glitches.

In some cases, resetting all settings to factory helps, but before that, it is recommended to make a full backup of the data. Software failure can be caused by a driver conflict after the system update, and a full reset returns all configuration files to the original state.

Influence of protective glasses and accessories

One of the most common causes of sensor malfunction is poor-quality protective glass or film, and if the glass has a black perimeter frame that covers the sensor area (even partially), it creates a permanent shadow that the system perceives as an object approach, which causes the screen to go out as soon as the call begins.

Thick cases with high sides can also be a problem. If the side of the case hangs over the top of the screen, it can reflect the infrared beam back into the sensor, creating a false alarm. Remove the case and check the sensor in the naked form - this is an easy way to exclude the influence of accessories.

For models with a subscreen sensor, the quality of the glue that glues the protective glass is critical. Bubble of air or dust in the sensor area can distort the readings. When replacing glass in the service, always check whether it is compatible with your Xiaomi model, especially if it is for devices with narrow frames.

💡

The quality of the protective glass directly affects the performance of the sensor. Use glass with a transparent area above the sensor or special versions for Xiaomi with a cutout.

Frequent Questions and Answers (FAQ)