The proximity sensor problem on Xiaomi smartphones, especially the legendary Redmi Note 3, is one of the most common user complaints: The screen goes out during a conversation, and you can’t complete a call or switch to speakerphone, or, conversely, the screen does not turn off at all and you cheek-drop contacts. Device owners often face the fact that regular funds do not help, and the screen continues to behave unpredictably, this is due to software failures in the firmware or contamination of the optical sensor.
Fortunately, in most cases, you can fix this without going to the service center. You'll need to do a few sequential steps, from simple cleaning to deep calibration through the engineering menu. It's important to understand that the proximity sensor is an infrared sensor that responds to reflected light, so any film or dirt can distort its readings. We'll take all the methods, from simple to complex, so you can restore normal operation of your gadget.
Before you start complex manipulations, it is worth checking the physical condition of the top of the screen. Often the problem lies in the banal contamination or the improperly pasted protective film that blocks access to the infrared beam. If the physical part is OK, then the reason lies in the software that requires adjusting the sensitivity of the sensor. Next, we will look in detail at the algorithm of actions to correct the malfunction.
Diagnostics and preparation for calibration
The first step before any setup is to accurately diagnose the current state of the sensor. Xiaomi and Redmi smartphones have built-in engineering test that allows you to see the raw data from the sensor in real time, which will help you understand whether the sensor is working at all or it is completely out of order. To run the test, you need to open the standard application "Phone" and type in a special code.
Type ##6484## into the dialing field. Immediately after entering the last digit, the CIT menu will open. In the test list, find the "Proximal sensor" or "Proximal Sensor." Click on it. You'll see two values: Value and Max. When you close the top of the screen, the value should change, usually from 0.0 to 5.0 or from 255 to 0, depending on the firmware version.
If the values don't change at all when you close and open the sensor with your hand, the problem can be hardware. However, if there are changes but they happen too slowly or with a delay, software calibration will help correct the situation, and it is also worth checking whether the In-pocket mode is included in the locking settings, as it often conflicts with the sensor that is not working correctly.
It is important to note that before calibration, you need to remove the protective glass if it has a black frame at the edges. Many users do not even suspect that it is the decorative glass frame that covers the IR port. Make sure that there is no dust and grease in the area of the speaker. Wipe the screen with a microfiber dipped in alcohol solution to exclude the influence of external factors on the test results.
Calibration methods through the engineering menu
The main way to restore the correct operation is to use an embedded engineering menu that is hidden from the average user, which is a method that does not require super-user rights (Root) and is data-safe. It allows you to overwrite the thresholds at which the system believes that the phone is near the ear, a process that takes no more than two minutes if you follow the instructions.
After you log into the CIT menu using ##6484## and select "Proximal sensor," notice the buttons at the bottom of the screen. There should be a "Calibration" or "Calibration" button. Press it. The system will ask you to remove your hand from the top of the screen and press "OK," and then, on the contrary, close the sensor tightly with your palm and press "OK" again.
At that point, you write the new reference values into the controller's memory, and if the calibration is successful, you'll see a message called "Pass" or "Success." If the test is completed with an error, try repeating the procedure, but this time press your palm a little tighter or leave a micro gap. Sometimes the sensor requires a more accurate positioning of the hand to correctly read the minimum and maximum light.
☑️ Calibration checklist
⚠️ Warning: If you still get Fail status after three calibration attempts on the engineering menu, don't try to do it indefinitely, which could indicate that the sensor plume has moved away from the motherboard or that the sensor itself is physically damaged.
There is also an alternative way through the recovery menu, but it doesn’t work on all firmware versions. MIUI. Try turning off the phone completely. Then press the Volume Up button combination. + In the Recovery menu, select a language (if available) and find an item "PCBA There may also be an option to check and reset sensors, although the functionality in Recovery is often stripped down compared to that of the other devices. CIT-menu.
Using third-party applications to set up
MIUI hardware sometimes doesn't work properly because of the specific build of the operating system, and in these cases, specialized tools from the Google Play Store come to the rescue, and these applications have more flexible sensitivity settings and can force the sensor configuration files to be overwritten, ignoring system constraints.
One of the most popular and proven solutions is the Proximity Sensor Reset/Fix app. Once installed, launch it and provide the necessary permissions. The app will suggest you choose a model of your device from the list - find Redmi Note 3 (codenamed kenzo or kate).
It takes about 10-15 seconds. The app will take a series of measurements and write the new values into the system calibration file. Once complete, be sure to restart your smartphone to make the changes take effect. Many users note that third-party software copes where the standard engineering menu passes, especially on custom firmware.
Another useful utility is the Proximity Sensor Calibration. It allows you not only to calibrate, but also to completely disable the sensor, if you are willing to put up with the fact that the screen will not go out in your pocket (but you can adjust the timer damping).
Solving the problem through hidden MIUI settings
In the operating system MIUI There's a hidden developer menu that gives you access to additional hardware settings, and sometimes the problem is not solved by calibrating, but by changing the logic of the sensor" → "About the phone and click on the version seven times MIUI.
Then, in the "Advanced" or "Advanced Settings" section, you'll see "Developers" on the "Developers" section. Inside this menu, scroll down to "Input" or "System" section. Find the "Advance Sensor" option (may be called "Proximity sensor check"). Make sure the switch is activated. There may be an "Deact the proximity sensor during the call" item - you shouldn't turn it on, but it confirms that the sensor is seeing.
| Parameter | Recommended value | Description of the impact |
|---|---|---|
| Approximation sensor | Included. | Activates the hardware sensor |
| Pocket mode | Off (for test) | Excludes programmatic conflicts |
| Windows animations | 0.5x or 1x | Reduces the load on the processor when calling |
Also, in the hidden settings, you should pay attention to the speed of animations. Although this is not directly related to the sensor, reducing the load on the interface can remove the lags that cause the screen to not react to the approach of the object. Set the scale of the animation of windows and transitions to a value of 0.5x. This will make the interface more responsive.
⚠️ Warning: Be careful in the "Developers" menu. Do not change the values that are not sure, especially those associated with the modem or radio module, as this may lead to loss of communication.
If you find a "Disable proximity sensor" item in the developer menu, try to switch it. Sometimes a full state reset by turning it off and then turning it on helps the system reinitialize the device driver. After manipulation, be sure to reboot the device completely, not just turn off the screen.
Hardware causes and physical repairs
If software methods, including engineering menus and third-party applications, fail, there is a high probability of hardware failure. In Redmi Note 3, the proximity sensor is located on a plume connecting the bottom board to the main board, or integrated into the top of the display module. Over time, the contact can oxidize or move away.
To test the physical defect hypothesis, you need to disassemble the device in a partial manner, you need to carefully remove the back cover (it is plastic and is removed around the perimeter), unscrew the screws of the plastic frame and access the main plume. Find the connector that goes to the top of the screen (usually signed or has a characteristic location).
A common problem with this particular model is to unplug the rubber cuff that directs light from the sensor. It's under the speaker. If this gum is shifted or lost, the sensor will go blind or see a permanent obstacle. Restoring the position of this rubber gasket solves the problem in 80% of hardware failures on the Redmi Note 3.
In case cleaning contacts and checking the cuff did not help, it is possible that the sensor module itself failed. Xiaomi often has the practice of replacing the entire top plume (assembled with volume and on buttons), since the sensor is soldered on it. The cost of such a part is low, and it takes about 20-30 minutes to replace if you have tools.
Prevention and additional recommendations
To keep the proximity sensor problem from returning, it is important to follow simple rules of operation: Do not let moisture enter the area of the speaker, as contact oxidation is the main enemy of electronics. Regularly wipe the top of the screen, removing skin fat, which creates a film that distorts IR rays.
When buying safety glasses, choose models with a speaker cutout or a transparent zone at the top. Black frames of cheap glasses are a common cause of problems after replacing the screen. If you use a case with high sides, make sure that it does not block access to the top edge of the smartphone.
Periodically, every few months, check the sensor through the engineering code ##6484##. This will take a minute, but will allow you to notice the drift of the readings and recalibrate the device before it becomes critical during an important conversation.
Remember that software failures can occur after the system update. If the sensor stopped working after the MIUI update, try resetting to factory settings (with a pre-backup), this will eliminate conflicts between the old configuration files with the new firmware version.