How to check the light sensor Xiaomi: the full guide

Modern Xiaomi smartphones are equipped with many micro-components that provide comfortable use of the gadget, but often remain invisible to the user until the moment of failure. One of these elements is the proximity and light sensor located at the top of the screen, which is responsible for automatically turning off the display during a conversation, so that the cheek does not press unnecessary buttons, and adjusts the brightness depending on the environmental conditions.

When this module starts to work incorrectly, the owner faces serious inconveniences: the screen goes out in the middle of an important call or, conversely, the phone hangs on the ear until the interlocutor has long since finished the conversation. Checking the health of this component is the first step before going to the service center, since often the problem lies in a software failure or contamination, rather than a physical breakdown.

In this article, we will take a look at all the diagnostic tools available, from built-in system tools to third-party utilities, how to interpret the data and what to do if the sensor shows incorrect values, and competent diagnostics will save time and possibly avoid unnecessary repair costs.

Symptoms of approximation sensor malfunction

Before running complex tests, it is worth carefully analyzing the behavior of your Xiaomi in everyday scenarios. Often the signs of a breakdown are obvious, but users ignore them, considering it a temporary system bug.

If you hold your phone to your ear, the screen doesn't go out, but it keeps glowing, it's a direct signal that the proximity sensor isn't picking up the object. In reverse, when the screen turns off immediately after the call starts or flashes when you're talking on speakerphone, you can talk about false positives. You should also pay attention to automatic brightness control.

• 📱 The screen does not turn off when you bring the smartphone to your face during a conversation.
• 📱 The display goes off spontaneously without physical actions on the part of the user.
• 📱 Automatic brightness works in jerks or does not respond to changing lighting.
• 📱 Video recording or viewing photos are interrupted due to false sensor activation.

It is important to distinguish between software glitch and physical failure, and if the problem occurs in only one particular application, such as Viber or Telegram, then it is most likely to be the optimization of the software, but if the failure occurs in the standard bell ringer and other system functions, a deep check of the hardware is required.

⚠️ Note: If the screen goes out only when using a wide black bezel or thick cover, the problem may be mechanically overlapping the sensor, not its breakdown.

Ignoring these symptoms can cause you to accidentally hang up or dial the wrong number during an important conversation, and early diagnosis can identify a problem at an early stage when it can still be solved by software or simple cleaning.

Use of the built-in CIT engineering menu

The most reliable and accurate way to test a light sensor on Xiaomi is to use a built-in engineering menu known as the CIT (Customer Integration Test), which is designed for factory diagnostics and allows you to test each module of the smartphone separately, bypassing the operating system and third-party applications.

There are several ways to log in to the diagnostic menu, but the most versatile is to use a special code in the call app. Open the standard "call" and type the combination ##6484##. If the code is entered correctly, the system will automatically redirect you to the test menu.

In the list that opens, you'll find the item associated with the proximity sensor, which is usually called the Proximity sensor or just Proximity. When you click on it, you'll see a screen with numerical values and color indications. In a normal state, when nothing covers the top of the screen, the value should be 5.0 (or close to 5), and the color of the indicator should be green.

Close the top of the screen with your palm, or hold your finger to the speaker area, and if the sensor is in good working order, the value will change to 0.0 and the color will turn red, and if the numbers do not change or fluctuate without physical contact, this indicates a malfunction.

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Special attention should be paid to calibration. If you see the values change in the test but do not reach the extreme points (for example, show 2.0 instead of 0.0 at closing), recalibration may be required. For this, some versions of the firmware have a separate Calibrate button that you press, close the sensor, and then remove the hand.

Diagnostics through the application "Services and feedback"

In the newer versions of the MIUI and HyperOS shell, Xiaomi is gradually hiding direct access codes to the engineering menu, preferring to bring diagnostic tools to the system application Services & Feedback, which is more user-friendly and does not require memorizing complex combinations.

To get to the right section, open your smartphone settings and look for the About Phone item. The top of the screen often features the MIUI version logo, but we're interested in the Services and Feedback menu, which can also be found through a search by settings. Inside the app, go to Device Check.

Here's a list of all the components you're testing. You can find the proximity sensor on the list and run the check. The interface is like the engineering menu, and you'll be asked to cover the top of the screen with your hand, and the system will determine whether the sensor is responding, and it will give you a "passed" or "not passed."

• 🔍 Allows you to check not only the sensor, but also the accelerometer, gyroscope and screen.
• 🔍 It has a more intuitive interface with explanations for each stage.
• 🔍 The result of the check can be sent to technical support Xiaomi.

The advantage of this method is that it's integrated into the overall diagnostic system, so if you don't pass the test, the app can immediately suggest sending an error report or recommending that you contact the service, so you don't have to take screenshots or memorize numerical values.

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The Service and Feedback app is the most relevant method for the new Redmi and Xiaomi models, as direct direct communication is the most important. USSD-Codes may be blocked by the manufacturer in the latest security updates.

It’s worth noting that this application requires an active Internet connection to allow some functions to function properly, although basic sensor validation often works offline. If the application requests an update of diagnostic components, agree to this for the most accurate results.

Checking with third-party utilities from Google Play

If Xiaomi’s built-in tools are not available for some reason or you want more detailed technical information, third-party apps will come to the rescue. There are many utilities in the Google Play store that specialize in reading data from various smartphone sensors.

One of the most popular and proven programs is Phone Doctor Plus or Sensor Test, which not only detects the fact of the alarm, but also builds graphs, shows raw data and allows you to compare the performance of your device with reference values, which is especially useful when you need to understand whether the sensor is “glutching” or running stable, but with an error.

After installing the app, run a proximity sensor test. Usually the process looks like a game: you need to close the top of the phone to stop the timer or change the color of the screen. Such utilities often have a calibration function that can help if a software failure is caused by downed settings.

Using third-party software offers the benefit of detail, such as AIDA64, which will show the sensor’s exact name and current state in real time, which can be useful for advanced users, but it’s worth remembering that such applications require permission to access the system, which can theoretically carry privacy risks.

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When installing applications for testing, pay attention to permissions. To operate the proximity sensor, the application only needs access to the appropriate sensor, requesting contact rights or SMS is suspicious.

Some tools allow you to log value changes, which helps to identify intermittent faults that are difficult to catch in a quick manual test. If you plan to carry your phone to the service, a printed log from such an application can be a weighty argument.

Calibration of the proximity sensor on Xiaomi

It is often the case that the sensor is physically correct, but