Xiaomi Redmi Note 7 is one of the most popular devices in its price segment, but its design has a characteristic feature: the proximity sensor is not located in a classical place above the speaker, but hidden under the screen at the top of the display. This engineering solution has allowed manufacturers to reduce the size of the upper frame, but often causes incorrect operation of the sensor during phone conversations.
Users often experience screens that go out spontaneously or don’t respond to a phone being held to their ears because the software reads an optical sensor that may be blocked by a protective film or contaminated. The main reason for false positives on the Redmi Note 7 is the shift of the protective glass or film that override the infrared emitter.
Before you take a device to a service center or try to disassemble it, you need to conduct a thorough software diagnostic. There are several effective ways to determine whether a problem is a hardware failure or a calibration failure. In this article, we will discuss in detail the methods of verification through the engineering menu, special applications and visual inspection.
⚠️ Before you start any software manipulation, make sure that your battery is at least 30%, to avoid suddenly shutting down your device during the diagnostic process.
Visual diagnostics and cleaning of the sensor area
The first step should always be an external inspection, because 80% of the time the problem is physical obstacles. The sensor on the Redmi Note 7 is in a narrow strip above the display, and even a microscopic crack on the protective glass can distort the signal. Carefully wipe the top of the screen with a soft microfiber dipped in alcohol solution, removing fat and dust.
Notice the protective film or glass. If they're not perfectly flat and they're blocking the sensor, they're going to cause constant false alarms. Try to gently peel off the edge of the protective coating at the top and see if the screen behavior changes during the call. Often, the optical sensor just doesn't punch through a thick layer of cheap protective glass.
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Use a flashlight angled to the top of the screen to see the exact location of the sensor under the glass, which will help you to more accurately assess the degree of contamination or film displacement.
If no visual defects are found, go to software tests. It's important to understand that even a clean screen doesn't guarantee correct performance if a software calibration is knocked down. In some cases, a simple device reboot helps, which resets temporary driver errors.
Checking through CIT's engineering menu
The most accurate way to test the health of all components of a smartphone is to use the built-in CIT (Customer Integration Test) menu, which is designed for factory diagnostics and allows you to test each module separately, including the proximity sensor. To enter the menu, you need to open the standard Phone application and type a special code.
Enter ##6484## in the dialer. The menu will open automatically, without having to press the call button. In the list that appears, look for the Proximity sensor (usually at the beginning or middle of the list, the numbering may vary depending on the version of MIUI).
☑️ The test algorithm in CIT
During the test, the screen will change color or show distance in centimeters. If you hold your hand and the values do not change or change with a long delay, this indicates a problem. Also in this menu you can see the current state of the sensor: Near (close) or Far (far). If the phone is on the table but shows Near, then the sensor is stuck.
| Parameter | Normal condition | Sign of malfunction |
|---|---|---|
| Standby regime | Far (far away) | Near (close) without obstacles |
| Reaction on the hand | Instant (up to 0.5 seconds) | Delay of more than 1 second |
| Testimonies. | 0 cm (hand at screen) / 5+ cm (far) | Constant jumps in values |
| Colour of the display | Green (success) | Red or no reaction |
Diagnostics through hidden menu Xiaomi
There is an alternative way to log in to diagnostic tools that sometimes works more stable than direct code entry. Go to Settings → About Phone → MIUI version. You need to quickly click 7-10 times on the firmware version icon until the notification “You became a developer” appears.
Once the developer mode is activated, a new option, Advanced Settings, or a separate Engineering Test menu, will appear in the settings menu, and the functionality is similar to CIT, but the interface may be more user-friendly. Select the Proximity Sensor test and follow the instructions on the screen.
What if the code doesn't work?
It is important to test at a screen brightness of about 50-70%. Too low brightness can not illuminate the sensor, and too high can create excessive glare that prevents the correct reading of the reflected signal. If this menu sensor works perfectly, then the problem lies in third-party applications or system settings.
Use of third-party applications for the test
If Xiaomi’s built-in tools are unavailable or have mixed results, you can use proven utilities from the Google Play store. Apps like Phone Test, Sensor Test or AIDA64 allow you to get a detailed graph of the sensor readings in real time.
Run the app you select, and find the partition that's responsible for the proximity sensor. Unlike a simple on/off test, these programs show numerical values. You'll see a graph that should be flat when the phone is on the table, and change dramatically when you close the top of the screen with your palm.
- 📱 AIDA64 — Shows detailed technical information about all sensors and their current status.
- 📊 Sensor Kinetics – allows you to visualize data from the sensor in the form of beautiful graphs and diagrams.
- 🔧 Phone Doctor Plus – conducts a comprehensive check of all the functions of the phone, including multi-touch and accelerometer.
The advantage of third-party apps is that they can show the sensor noise, and if the values jump randomly even without touching, it can indicate electrical interference or a plume malfunction, details that Xiaomi's standard engineering menu often doesn't display.
Calibration of the proximity sensor
Often, the sensor is physically fit but not calibrated to specific conditions (e.g., after changing the screen or pasting the glass). To correct this situation, the calibration procedure is intended. Go to the CIT engineering menu and select Proximity sensor.
A Calibration button will appear on the screen. Press it and remove your hand from the screen. The phone will ask you not to touch anything to record the value of "far away." The system will then automatically record the new baseline values. In some versions of MIUI, you may need to hold your finger to the sensor at the request of the system.
⚠️ Warning: During calibration, the phone must lie on a completely flat, matte, dark surface, and the bright or mirrored surfaces under the screen can distort the settings.
After a successful calibration, the device will ask to restart. Don't ignore this step, as the new parameters only come into effect after the full cycle of the system's activation. If the calibration is error-prone or the results are immediately reset, the sensor module itself or its plume may be damaged.
Effects of protective accessories and glare
Many Redmi Note 7 users have noted that the sensor problem arises when the new protective glass is glued, because the optical sensor works by emitting infrared light and analyzing the reflected signal, and thick or poor-quality glass can scatter this beam without allowing it to return to the receiver.
Also, consider the lighting conditions. Direct sunlight hitting the top of the screen contains a powerful infrared spectrum that can blind the sensor to the fact that it is constantly in front of an object, in which situations the screen can go out in your pocket or when talking outside.
- ☀️ Avoid direct sunlight directed at the sensor area during a conversation.
- 🧼 Rub the screen regularly as the fat layer changes the refractive index of light.
- 🛡️ Use protective glass with a sensor cutout or marked as “Compatible with Face” ID/Proximity».
If you notice that the security glass sensor is worse, try temporarily removing it and running tests again, which is the surest way to know if the accessory is the cause of the malfunction, sometimes it helps to replace the protective coating with a thinner or better one.
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The quality and proper gluing of the protective glass solves 90% of the problems with the proximity sensor on the Xiaomi Redmi Note 7.