The situation of spontaneously pressing screen buttons on the Xiaomi Redmi 9 during a phone conversation is familiar to many users. This is not only annoying, but can lead to an accidental call reset, turn on the speakerphone or, worst of all, to inadvertent dialing from the contact book. The problem often lies in the operation of the proximity sensor or features of the MIUI shell software that misinterpret touches.
Diagnosing a malfunction requires a consistent approach, as the causes can range from banal contamination of the screen to hardware damage to the display plume. Owners of budget models often find that the proximity sensor is not working correctly, which causes the screen to not go out when the phone is held to the ear.
In this article, we will look at all possible ways to fix this problem, from simple software settings to complex engineering manipulations, learn how to accurately calibrate the sensor, check the operation of hidden system utilities and determine whether your device needs hardware repair.
Reasons for Phantom Presses During a Call
The main culprit behind the chaotic taps is the incorrect approach sensor. In the Redmi 9, this sensor is located at the top of the screen. If the software thinks the phone is not held to the ear, the screen remains active, and any touch with the cheek or finger at that point is perceived by the system as a command.
The second common cause is the use of poor-quality protective glass or film. Thick glass can shift the touch point or interfere with the capacitive layer, and the problem can be in static electricity, which accumulates on the surface of the display, especially in dry rooms or when wearing a phone in synthetic clothing.
Do not exclude software failures of the shell MIUI. Conflicting applications, bugs in system updates, or crowded cache can cause touchscreen to freeze. Sometimes phantom clicks occur because the process responsible for phone calls consumes too much resources and does not have time to process signals from the sensor.
⚠️ Note: If the problem appeared immediately after the fall of the smartphone or moisture entering the body, most likely, the display plume or the touchscreen controller itself is damaged.
Diagnostics and calibration of the proximity sensor
The first step in solving the problem should be to check the performance of the sensor. In Xiaomi smartphones, there is a hidden engineering menu, accessible through the dialing code, which is the most reliable way to know whether the phone sees an object in front of the screen.
To enter the test mode, open the Phone app and dial the combination ##6484##. Once you enter the last digit, the CIT menu will open. Find the "Proximity sensor" or "Proximation Sensor" item in the list. Click on it.
In the window that opens, you'll see a graph or numerical values. Hold your hand to the top of the screen and remove it. If the values change (e.g., from 5.0 to 0.0 or vice versa), the sensor is intact. If there is no reaction or the values "jump" without touching, calibration is required.
☑️ Testing of the proximity sensor
To calibrate in the same menu, press the Calibration button. You will need to close and open the sensor several times with your hand, following the instructions on the screen. Once you have successfully completed the procedure, press Pass or Save. This action resets the current sensor sensitivity settings.
What if the code doesn't work?
Sensitivity adjustment and avoiding false positives
If the sensor is working normally but the screen is still responsive to the cheek touch, it's worth checking the sensitivity settings. Some versions of MIUI have a "Pack Mode" option that is designed to block random taps, but sometimes it doesn't work properly.
Go to Settings → Lock and Protect → Mode in your pocket. Try changing the state of the switch. If the function is on, turn it off, and vice versa. Also, you should pay attention to the option “Increased Sensitivity” (if available in your version of the software), which is designed for use with protective glasses.
It's important to check if touchless controls or gestures that might conflict with normal use are enabled, and turn off all unnecessary screen interactions in the special features menu, which will help isolate the problem.
| Parameter | Where to find out. | Recommended value |
|---|---|---|
| Pocket mode. | Settings → Blocking | Off (for the test) |
| Screen sensitivity | Settings → Screen | Standard. |
| Gestures and shortcuts | Settings → Additional | Minimum |
| Autobrightness | Notification curtain | On (assisting sensor) |
Another nuance is the brightness of the screen, and if you set the minimum brightness, the capacitive layer may work less steadily, so try to increase the brightness during a conversation or turn on the autobrightness so that the system adjusts the lighting itself depending on the lighting.
Cleaning the system and resetting the settings of the “Phone” application
Software junk often causes strange smartphone behavior, apps accumulate cache over time that may contain erroneous data about the sensors or the call interface, and cleaning up that data is a safe procedure that doesn't affect your personal contacts.
Go to Settings → Apps → All Apps. Find Phone (or Calls, Dialer depending on version) and click Storage and select Clear Cache and then Clear All (or Reset) and repeat the same procedure for Contacts.
After cleaning, it is recommended to restart the device, which will allow the system to re-initialize all services associated with the communication module, and if the problem was caused by a temporary software failure, it should disappear.
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Before resetting your phone app settings, make sure your important numbers are saved to your Google account or on your phone. SIM-card, although clearing the cache usually does not remove contacts, reinsurance will not interfere.
If the cleanup didn’t work, check for system updates. Go to Settings → About Phone → MIUI version. Sometimes Xiaomi releases patches that fix specific sensor problems of specific models. Install updates if available.
Checking protective accessories and screen
Often, Redmi 9 owners forget that a protective glass that was pasted three years ago could have become unusable: microcracks, bubbles of air at the edges or just a layer of fat and dirt can disrupt the electrostatics of the screen.
Also, look at the screen itself with the lights off, and if you see rainbow spots, stripes, or areas with altered color reproduction, it's a sign of damage to the matrix or touchscreen, in which case, "dead zones" or, conversely, sensitive areas will interfere with normal operation.
Note the charger. Using cheap power supplies without certification creates a lot of interference in the network, and when you connect such a charger during a conversation (which happens during long conversations), the screen can begin to “live its life” due to tips.
⚠️ Warning: Never use your phone while charging if the power supply is causing interference on the screen.This is not only inconvenient, but also dangerous for the battery and power controller.
Wipe the screen with a special wipe for monitors. Alcohol-containing liquids are best avoided often, as they can damage the oleophobic coating, which will increase friction and static electricity.
Radical measures: dumping and hardware repairs
If none of the software methods work, you have to do a full factory reset, which will delete all the applications and data, and put the phone back out of the box. Make sure you back up important files before you do this.
To reset, go to Settings → About Phone → Settings Reset → Erase all data. After you reboot, don't install all the apps at once. Check the call performance on a clean system. If the problem persists, it's the hardware.
In the Xiaomi Redmi 9, the proximity sensor is often integrated into the display plume or located under the screen. When the contact could move, the touchscreen controller itself could also fail.