How to check sensors on Xiaomi: full instructions

The modern smartphone is a complex electronic organism, where software is inextricably linked to physical sensors. Sensors on Xiaomi play a critical role in everyday use of the gadget, from automatically adjusting the brightness of the screen to navigating in space. When any of these components fails, the user immediately faces discomfort: the screen does not go out during a conversation, the compass shows the wrong direction, and the pedometer stops recording the distance traveled.

Checking the functionality of sensor modules is the first step in diagnosing problems that separates software failure from physical failure. Mi and Redmi device owners often wonder how to quickly and accurately identify a malfunction without going to a service center. Fortunately, the company's engineers have built-in testing tools that are hidden from the average user but are accessible through special commands.

In this article, we will take a look at all the available methods of verification, look at the nuances of the engineering menu and discuss what third-party applications can be useful in difficult cases. MIUI and HyperOS offer powerful self-diagnostics, allowing you to check the accelerometer, gyroscope, proximity sensor and many other elements in a matter of minutes.

Using the CIT Engineering Menu for Diagnostics

The most reliable and in-depth verification tool is the built-in engineering menu, often called the CIT (Customer Integration Test), a special section of the system designed to factory check the build quality before selling the device, and you can access it through the standard Phone app by dialing the secret code ##6484## or ##64663#. Once you enter the last digit, the menu will open automatically, without having to press the call button.

Inside the CIT interface, you'll see a complete list of all the hardware modules in your Xiaomi smartphone, and you'll see a list of dozens of items that each correspond to a particular sensor or function, like "Proximity" for the proximity sensor, "Accelerometer" for the accelerometer, and "Light sensor" for the light sensor. When you click on any of those, you run a specialized test.

⚠️ Warning: Be careful when testing features related to recording sound or vibration if the smartphone is in a quiet place or near people.Some tests may make loud noises or cause strong body vibrations.

The peculiarity of this method is that it checks hardware, not the operating system, and if the CIT test shows a FAIL, then the problem is likely hardware, and if the test is successful, but there are failures in normal operation, then the cause is the software or the application conflict.

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If the code ##6484## doesn't work, try entering it in the Phone app without pressing the call button. CIT This may be limited, so you will need to install a special APK-file.

Checking the proximity and illumination sensor

The two most commonly used sensors at the top of the screen are the proximity sensor and the light sensor. The first is needed to dampen the screen during a conversation so that the cheek does not reset calls, and the second automatically adjusts the brightness of the display depending on the environmental conditions. In the CIT engineering menu, these tests are usually combined or in succession.

To check the proximity sensor, the system will ask you to close the top of the screen with your hand and then remove it. The screen will display distance in centimeters or status "Near" (close) and "Far" (far) If the values do not change or change with a long delay, it is possible that the screen is contaminated or a low-quality protective glass overlapping the sensor is pasted.

Testing the light sensor requires changing the environment, so you'll have to cover the top end of the phone with your hand, simulated being in your pocket, and look at the change in the digital values of the luxmeter. The brightness of the screen should respond instantly. If the automatic brightness is not working properly, the first thing you do is check the cleanliness of the area around the speaker.

• 📏 Make sure the protective film does not cover the sensor area.
• 🧹 Wipe the top of the screen with a soft cloth of fat and dust.
• 🔄 Reboot the device if after calibration the sensor continues to "glutch».

Diagnosis of accelerometer and gyroscope

The accelerometer and the gyroscope are the vestibular apparatus of your smartphone, which are responsible for the autorotation of the screen, the control in games, the operation of the pedometer and navigation applications. The failure of these modules makes it impossible to use augmented reality (AR) and many fitness functions. CIT-The menu usually requires physical action with the device.

When you run the accelerometer test, you'll see a level or a ball on the screen, and you'll have to put your phone on a flat horizontal surface and press the calibration button, and the system will read the current position and take it as zero, and then you'll have to tilt the phone in different directions to watch the cursor or air bubble react.

The gyro is tested in a similar way, but with higher accuracy requirements, virtual reality and panoramic photography depend entirely on its correct operation. VR-glasses or when watching 360 videos° moving in jerks or with a delay, recalibration is necessary).

It is important to understand that software failure of the motion sensor is often solved by simple calibration, but if after calibration in a horizontal position the phone continues to show a tilt, this may indicate a physical displacement of the module inside the housing after falling.

Testing of the magnetometer and GPS-module

Magnetometer (electronic compass) and GPS-The module is responsible for geolocation. Without them, the maps will show your location with a large margin of error or will not determine the direction of movement. Unlike other sensors, these modules are highly dependent on external magnetic fields and the quality of the signal received from satellites.

In the magnetometer test mode, you're asked to draw a figure of eight with your phone in the air, which is necessary to reset the accumulated magnetic interference and fine-tune the sensitivity. If the test doesn't pass the first time, try to move away from metal objects, computers and sources of strong electromagnetic radiation.

GPS testing requires access to open spaces. Indoor satellite signal is too weak for accurate diagnosis. In the test menu, you will see a list of visible satellites and their signal strength. Positioning accuracy depends on the number of satellites captured (ideally more than 8-10).

Checking the fingerprint sensor and face scanner

Biometric sensors are a key security element. The fingerprint scanner in modern Xiaomi models can be embedded in the screen (optical) or placed on the side edge (physical). Face ID sensor uses a front-facing camera and AI algorithms to analyze facial relief.

In the engineering menu, a fingerprint test will require you to re-register your finger in test mode and try to unlock the device. The system will assess the recognition rate and the success rate. If your finger is dry or wet, the test may not pass, so it is recommended that you wipe your hands before diagnosis.

Face ID is usually integrated into front-facing camera testing, but newer versions of HyperOS have a separate feature: the algorithm not only checks the presence of a face in front of the camera, but also the response to head turns. Infrared sensor (if it is in the model) is also tested for the ability to work in complete darkness.

⚠️ Warning: Don’t try to disassemble the fingerprint scanner module yourself.This is a sensitive element that, after being replaced, requires a motherboard binding, otherwise unlocking won’t work.

If the built-in tests show a biometric error, try removing old prints and faces from memory and registering them again, often software conflicts in the biometric database lead to false denials of access.

Third-party applications for detailed verification

The built-in MIUI tools are sometimes not enough to get detailed technical information, and in these cases, specialized applications from Google Play come to the rescue, allowing you to see raw data from sensors that are hidden in the standard interface, and conduct a deeper diagnosis.

One of the most popular tools is the Sensor Test app, or Phone Doctor Plus, which provides real-time data visualization, and you can see the accelerometer readings, the exact magnetic field values, and the status of all the sensors that are connected.

• 📱 Sensor Test: Shows a list of all available sensors and their status (working/not working).
• 📊 CPU-Z: Provides information about the system, including data about the battery and some sensors.
• 🔧 TestM: a comprehensive application to test all the iron, including multi-touch and speaker.

Using third-party software is especially useful when it comes to understanding whether the system can see the sensor at all. CIT-menu item is, but the test gives an error, and in a third-party application the sensor is not even displayed in the list, there is a high probability of a physical break of the plume.

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Third-party applications cannot fix the breakdown, but they help to identify exactly which module stopped responding to the system’s requests.

Frequent problems and methods of their elimination

Even if the hardware is in good condition, users often experience sensor malfunctions due to software conflicts, such as calibration that may be lost after a firmware update, or a third-party application may block access to the sensor, in which case resetting or recalibration helps.

One common problem is sticking the proximity sensor, and the screen may not light up when you hold the phone to your ear, or it may go out while watching video, often by cleaning up the cache of system services or removing newly installed applications that have access to the sensors.

If the software methods don't work, and the engineering menu tests fail, then only hardware repairs remain, which can be a plume replacement, a contact cleaning, or a complete sensor module replacement. In modern Xiaomi smartphones, sensors are often soldered into a common board or integrated into a display module, which makes repairs more difficult.