Xiaomi Redmi 8 has proven to be a reliable budget device, but users often face a classic Android-segment problem: the incorrect operation of the proximity sensor, a situation when during a phone conversation the screen does not go out when you lift it to the ear or, conversely, lights up when you touch your cheek, causes serious discomfort, which leads to accidental shutdowns of the call or pressing unnecessary buttons.
The reason is software calibration failure or physical contamination of the upper body. Unlike flagship models, which use sophisticated laser distance detection systems, it uses an infrared sensor that requires fine tuning. Sensor calibration is a process that allows the system to correctly interpret the distance to the object.
In this guide, we will take a look at all the solutions available, from simple cleaning to deep engineering through a hidden menu, without needing special tools, enough attention and following instructions, and the proper operation of this module is critical for everyday use of the gadget.
Diagnosis and main symptoms of malfunction
Before you start complex manipulations, you need to make sure that the problem lies in the software part or contamination, and not in the physical damage to the plume. Often users confuse the software glitch with the hardware failure. The main signs that the proximity sensor is not working correctly include the lack of response of the screen to close the upper part of the case with the palm during the call.
Sometimes the screen can go out spontaneously, even when the phone is on the table and nothing is covering the top bezel, which means that the sensor is "seeing" a non-existent object, and you should also pay attention to the protective glass or film, if they are glued curved or have a dimming in the area of the speaker, this blocks infrared radiation.
To quickly check the functionality, you can use engineering code, which is the most reliable way to see if the system sees a change in the lighting of the sensor.
##6484##Once you enter the code, the CIT (Customer Information Test) menu will open. Find the "Proximity sensor" or "Proximity Sensor" item in the list. When you bring your hand to the top of the screen, the values should change from 5.0 (or Far) to 0.0 (or Near). If the numbers change, then (iron) is good, and you need software calibration.
Preparation of the device for setting
The effectiveness of the adjustment procedure depends on the condition of the smartphone surface. Even a thin layer of fat or dust can distort the readings of the infrared beam. Before starting work, you must carefully wipe the top of the front panel with a microfiber moistened in a special solution for the screens.
Note the case. Some of the safety cases have too high sides that can partially overlap the sensor's range. Remove the case while you're diagnosing and adjusting. Also check if there's a black-framed protective film on the screen that comes over the speaker.
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If you use a thick protective glass with a wide black frame, try gently cutting off part of the film above the sensor or replacing the accessory with a model with a notch under the sensor.
Make sure the battery is at least 30%. Although the calibration process is not energy intensive, suddenly turning off the device while writing the reference values can cause the system to reset. Close all background applications to ensure stable interface performance.
Calibration through MIUI Engineering Menu
The most effective way to fix the problem is to use the built-in MIUI engineering menu. This method does not require superuser rights (Root) and is safe for warranty. The CIT menu allows you to reset current values and write new benchmarks "close" and "far".
To enter Test Mode, use the standard code we mentioned earlier, or go through the settings. Open the Phone app and dial ###6484#. In the list that opens, find Proximity sensor. Click on it to enter Test Mode.
☑️ Calibration algorithm in CIT
Inside the menu, you'll see the current value and the Calibrate button. Press it. The system will ask you to remove all objects from the screen, and then, on the contrary, close the sensor (usually ask you to close the top with your hand). After passing the tests, be sure to press the Pass or OK button to save the results. If you just exit, the settings will not apply.
⚠️ Warning: Do not press the Fail or Back button until the process is complete, otherwise the calibration will be interrupted and you will have to start over.
Use of third-party applications for calibration
If the built-in menu is not available or effective for some reason, you can use specialized software from the Google Play store. Applications like "Proximity Sensor Reset & Calibration" or "Sensor Test" can interact with system drivers similar to the engineering menu.
The way these tools work is simple: they read raw data from the sensor and force a command to write new thresholds, which is especially useful if the standard MIUI interface is not working properly, but it is worth remembering that third-party software may request unnecessary permissions.
After installing the app, start the calibration procedure, which usually takes no more than 30 seconds, the program will tell you when to close the sensor and when to remove the hand. Once completed, be sure to perform a full restart of the smartphone, as the changes will only take effect after restarting the system.
Why can third-party applications not work?
Hardware causes and physical repairs
When software methods are powerless, the reason lies in the hardware. In the Redmi 8, the proximity sensor is structurally combined with the top speaker module and the front camera in a single board, a common problem is the drift of the plume or the oxidation of the contacts.
If the phone fell or was exposed to moisture, the sensor element itself could be damaged, in which case the calibration will be reset immediately after rebooting or show constant values (always 0 or always 5).
| Cause of malfunction | Symptoms | Method of decision |
|---|---|---|
| Sensor contamination | The screen goes out chaotically | Cleaning with a spirit napkin |
| Failure of the | The screen doesn't go out when you ring. | Calibration via CIT menu |
| The plume's retreat | Total lack of response | Reconnecting the plume in the service |
| Physical injury | Persistent false positives | Replacement of the speaker/sensor module |
The Xiaomi Redmi 8's self-disassembly requires care. The back cover is glued, and you need a hair dryer and a suction cup to remove it. If you don't have experience, you should go to the service center. Replacing the top speaker module (where the sensor is built in) is an inexpensive procedure that is guaranteed to solve the problem.
Sensitivity settings and additional parameters
In some versions of MIUI firmware, there is a possibility of fine-tuning the sensitivity, although this item is often hidden. Check Settings → Screen lock and password → Pocket mode. Disabling this feature can help if the phone reacts to the fabric in the pocket, confusing it with approaching the face.
Also worth paying attention to are optimizer applications: Aggressive energy saving can turn off the sensor to save charge, causing it to malfunction at the time of the call, add the phone book and the Phone app to the list of energy saving exceptions.
If nothing works, you can try resetting everything to factory settings, which is an extreme measure that requires backup, and resets eliminate deep conflicts of system files that could have affected the hardware drivers.
Prevention and useful recommendations
If the problem hasn't returned, follow simple rules of operation. Rub the top of your smartphone regularly. If you like watching videos horizontally while holding your phone around the edges, try not to cover the area above the screen with your fingers so as not to provoke false positives.
Keep an eye out for system updates. Xiaomi engineers periodically release patches that improve sensor performance. Update MIUI through the About Phone menu to get bug fixes.
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Regular cleaning of the top of the screen and using quality protective glasses with the right cutouts prevent 90% of proximity sensor problems.
Remember, the proximity sensor is an optical device, and any obstacle in its path will be perceived as an object, and the care of accessories and cleanliness of the device are the key to its long and stable operation.