Owners of the Chinese company’s popular smartphones often face the unpleasant situation of the device’s screen not turning off during a conversation. Instead of turning off the display when you touch the ear, the Xiaomi Redmi Note 8 Pro continues to glow brightly, leading to accidental cheek pressing and interruption of the interlocutor. This is a classic symptom of a proximity sensor malfunction that can be caused by both software failure and physical damage to the component.
The problem is not only relevant for older devices, but also for models that have been in use for several years. In most cases, it is early to panic: often the culprit is a protective glass, accumulated dust or a failure in the MIUI operating system. However, ignoring the problem can lead to increased battery consumption and discomfort when using the gadget.
In this article, we will take a closer look at all the possible reasons why the proximity sensor on the Redmi Note 8 Pro is not working, and provide step-by-step diagnostic instructions, learn how to calibrate through the engineering menu, check for hardware defects, and understand when it is time to carry your phone to the service center.
The main reasons for the failure of the sensor
The first thing to do before you start a complex manipulation is to eliminate the banal external factors, and users often forget that the top of the screen, where the sensor is located, is a low-quality protective film or thick tempered glass, which can block the infrared radiation that the sensor uses to determine the distance to the object.
Another common cause is trivial pollution, where you put dust, pocket pile and skin fat into the speaker grid and the sensor area, and it creates an opaque barrier, so the system can see that the object (your ear) is always next to the screen, and it can't catch fire, or it can't see the obstruction.
Software conflicts also lead the way in the list of reasons: After updating MIUI firmware or installing third-party applications to manage calls, drivers can be bugged. Redmi Note 8 Pro features an optical sensor built into the screen, making it more sensitive to software calibration settings compared to classic IR sensors.
⚠️ Note: If you have recently changed a screen or display module in an unauthorized service, there is a high probability of using a low-quality spare part. Cheap copies of displays often do not have a correctly working sensor plume, which makes software repairs useless.
To quickly check the status of the sensor, you can use the built-in diagnostics tools. Go to the phone menu, type ##6484## and select "Proximity sensor." If the value changes from 5.0 to 0.0 when you close the top of the screen with your hand, the tone part is good, and the problem lies in the settings.
Software calibration through the engineering menu
The most effective way to fix a software failure is to recalibrate, which is built into the CIT's special engineering menu on Xiaomi smartphones. It doesn't require root rights to access it, making it safe for the average user. It's important to do everything consistently, without missing steps.
First, open the Phone app and type ##6484##. The test list will open for you. Find the Proximity sensor. The window that opens will show the current readings. If you don't close anything with your hand, the value should be maximum (usually 5.0).
If the readings are jumping or not changing, press the Calibration button at the bottom of the screen, at which point the phone may vibrate or sound. Don't move your hand away from the screen until the process is complete. The system automatically detects the upper and lower thresholds of sensitivity and records the new values in the controller's memory.
☑️ Calibration checklist
After a successful calibration, be sure to press the "Pass" button to save the results. If the test is not passed, the system will prompt you to repeat the procedure. In some cases, you need to restart the device to take effect. If after three attempts, the calibration fails, this is a sure sign of hardware failure.
System settings and call applications
Sometimes the problem is not with the sensor itself, but with how the operating system processes its signals. There are additional features in the MIUI shell that can conflict with standard behavior. For example, In-Pack mode is designed to prevent accidental taps, but when the sensor is not working properly, it can lock the screen constantly.
Check lock settings. Go to Settings → Lock screen and find "Mode in your pocket." Try to turn off this feature and check the phone's performance in conversation. Also, look at the Phone app that makes calls. It may have a "Draw-up Sensor" setting that you need to activate.
If you use third-party calls (such as from Google or Truecaller), they may have their own screen control settings, in which case the system may receive conflicting commands from different applications, and it is recommended to temporarily return to the standard MIUI Dialer app to eliminate this factor.
And don't forget the Anti-Spa feature, which is often on by default, which prevents the screen from turning on when the phone is down. If the sensor is contaminated, this feature may not work properly, affecting conversation mode, and disabling this option in screen settings and locking can help diagnose.
Influence of protective accessories and covers
A seemingly obvious factor that is often overlooked: Many Redmi Note 8 Pro owners buy full-perimeter protection cases or black-framed protective glass, and if the black glass bezel even slightly overlaps the sensor area (it is next to the speaker), the sensor will receive distorted data.
Optical sensors, unlike IR sensors, are very sensitive to the transparency of the material above them, and even a microscopic crack in the protective glass in the sensor area or a strong fatty plaque can scatter light, making the phone "think" it's pressed against the ear. Remove the case and wipe the screen with a special solution before testing.
There is also a category of smart cases with magnetic fasteners or open-sensors, which can cause magnetic interference or physically close the sensor, and if the problem occurs immediately after you buy a new case, it is likely that it is the cause.
⚠️ Warning: When you stick a new protective glass, always use the template or frame that comes with the kit. 1-2 A millimeter upwards can completely block the approach sensor on the Redmi Note 8 Pro.
Hardware malfunctions and physical repairs
If software methods didn't work, you'll have to consider a physical breakdown. In the Xiaomi Redmi Note 8 Pro, the proximity sensor is integrated into the display module plume, which means that when you change the screen, the sensor is often changed, but if the phone fell or was hit, the plume connector could move away from the motherboard.
It can also oxidize the contacts, and if the device was exposed to a high humidity environment or got wet, the contacts could have been coated with an oxide film, which disrupts the signal transmission, requiring disassembly of the device, ultrasound or alcohol cleaning of the contacts, and reconnection of the plumes.
The most difficult case is the failure of the optical element itself, which is soldered into the design of the display, it is almost impossible to replace it separately. It requires replacing the entire display unit assembly. It is an expensive procedure, so make sure that you have a diagnosis before buying a new screen.
Parts difficulties
To do this, you can gently press the top of the screen in the speaker area, and if you press the sensor, it starts to react in the engineering menu, then the problem is that the plume is in poor contact or detachment from the matrix.
Comparison of diagnostic and repair methods
To make it easier for you to decide on what to do, we have prepared a summary table that will help you quickly identify the type of problem and choose the best solution without wasting time on unnecessary actions.
| Symptoms. | Probable cause | Method of decision | Difficulty |
|---|---|---|---|
| The screen doesn't go out when you talk. | Protective glass/film | Remove the accessory or cut the hole | Low. |
| The screen goes off on its own. | Sensor contamination | Cleaning the top of the screen | Low. |
| Sizing doesn't pass. | Failure of software or drivers | Resetting or flashing | Medium |
| No reaction in CIT test | Breakage of plume or breakage | Repairs at the service centre | Tall. |
As you can see from the table, most of the time, the problem is solved by simple methods, but if the "Difficulty" column indicates a high level, it is better not to take risks and turn to professionals, especially if the phone is on warranty.