The situation when smartphone screen remains active during a call is familiar to many users. This is not just a minor inconvenience: holding the phone to your ear accidentally presses virtual keys, turns on the speakerphone, or ends a call. Most often, the reason lies in the incorrect operation of proximity sensor, which is responsible for blocking the display when you bring the device to your face.
In some cases, the problem may be caused by a software failure of the system Android or physical contamination of the sensor. You should not immediately take the gadget to the service center. There are a number of actions that you can perform yourself to return functionality the phone to normal condition without extra costs.
We will look at the main causes of the malfunction and offer step-by-step diagnostic methods. From simple case cleaning to complex software calibration - these steps will help you understand where exactly the error lies and how to fix it effectively.
How the proximity sensor works and why it makes mistakes
The proximity sensor is a small module, usually located at the top of the screen, next to speaker. Its task is to determine the distance to an object. When you put the phone to your ear infrared emitter sends a signal that is reflected from the skin and returned to the receiver. The system receives the data and turns off the display.
If the screen does not go off, then the data transmission chain is broken. This can happen because the sensor is "dirty" or is "locked" in the "far" position by software. In modern models with screens like AMOLED or IPS the sensor is often hidden under glass, which makes it vulnerable to stickers and protective films.
Sometimes the problem is temporary. After rebooting the device, the controller's operating logic may be restored. However, if the failure recurs regularly, deeper intervention in the settings or physical testing of the components is required.
A common cause of false positives is a thick protective glass with a black frame blocking the sensor area. Try removing the case or film to check.
Primary diagnostics and cleaning of the device
First of all, it is necessary to eliminate banal physical obstacles. Dust, sebum or adhesive residue from the protective film can completely block the operation of the optical sensor. Carefully inspect the top frame of the screen in bright light.
Use a soft microfiber cloth and a special screen cleaner. Gently wipe the area around the earpiece. Do not use alcohol or aggressive chemicals, as they can damage the oleophobic coating or the sensor itself.
If you have a protective glass installed, make sure that it is glued evenly. A displacement of even a millimeter can block a critical area. Also check that the sensor is not blocked by a massive case with a high side.
- 🧹 Thoroughly wipe the top of the screen with an alcohol wipe (gently).
- 📱 Remove the protective glass or film to test the operation of the sensor.
- 🔍 Inspect the sensor area under the magnifying glass item of microcracks or dirt.
- 🔄 Reboot your smartphone after cleaning to reset the sensor cache.
Software calibration of the proximity sensor
If physical cleaning did not help, perhaps The software sensitivity settings have gone wrong. The system Android there is a hidden engineering menu that allows you to test and calibrate various modules, including Proximity Sensor.
To enter the diagnostic menu, you usually use a special code in the "Phone" application. The most universal code is #0# or ##4636##. However, on smartphones of different brands (Samsung, Xiaomi, Huawei), the codes may differ. If standard combinations do not work, try finding an application for the engineering menu in the application store.
Inside the menu, find the section Sensor or Proximity Sensor. Place the phone on a flat surface without covering the top with anything. The sensor value should be 5.0 (or "Far"). Place your palm to the top of the screen - the value should change to 0.0 (or "Near").
| Smartphone brand | Engineering menu code | Section to check | Normal value (hand removed) |
|---|---|---|---|
| Samsung | #0# |
Sensors > Proximity | 5.0 (Far) |
| Xiaomi / Redmi | ##6484## |
Proximity Sensor | 0.0 (depending on the version) |
| Huawei / Honor | ##2846579## |
Single Item Test | 1 (Far) |
| Pixel / Stock Android | ##4636## |
Sensor information | 0 (Near) / 5 (Far) |
If the values do not change or change chaotically, try pressing the button Calibration in the same menu. Follow the instructions on the screen: usually remove your hand, press the button, then close the sensor and press the button again. After successful calibration, reboot the device.
What to do if the codes do not work?
On some new versions of Android, access to the engineering menu via USSD codes is closed by developers. In this case, download the "Phone Tester" or "Sensor Box" application from Google Play to check the data in real time.
System settings and third-party applications
Sometimes the culprit of the problem is not the sensor itself, but the interface settings or third-party software. Certain power-saving features or control gestures may conflict with the system's default call behavior.
Check your accessibility settings. Features for people with disabilities, such as "Power button to mute ringer" or gesture controls, may take over control of the screen. Go to Settings → Accessibility and temporarily disable all active services.
It is also worth paying attention to applications for recording calls or identifying numbers. They often require access to the screen and can block you from turning it off. Try uninstalling recently installed telephony-related apps and check if the problem goes away.
⚠️ Attention: On some custom firmware (for example, MIUI or ColorOS) there are separate “Proximity sensor” switches in the advanced call settings. Make sure this option is enabled and not accidentally disabled.
If you are using a theme other than the standard one, try resetting it to the default one. Incorrectly modified system theme files can disrupt the logic of the interface during a call.
Third-party launchers and themes are a common cause of software conflicts. Returning to stock settings helps identify the culprit.
Resetting settings and updating software
When simple methods do not help, it is worth considering the possibility of a software failure in the operating system itself. Accumulated errors in the cache or an unsuccessful update can lead to incorrect operation of sensor drivers.
Before taking drastic measures, check for system updates. Developers often release patches to correct sensor errors. Go to Settings → About phone → System update and install the available software version.
If the update does not help, you can reset the settings to factory settings. This will delete all your data, so be sure to back up your contacts and files. After resetting, the phone will return to its “out of the box” state, which eliminates the influence of user settings.
☑️ Preparing to reset settings
After performing the reset, do not restore all applications from the backup copy at once. First, test the calls on a “clean” system. If the sensor works correctly, it means that the problem was caused by one of the previously installed applications.
Hardware faults and repairs
If software methods are powerless, there is a high probability of physical failure. The proximity sensor could fail due to shock, moisture, or a manufacturing defect. In this case, specialist intervention is required.
A common problem in old smartphones is the sensor cable coming off. If dropped, the connector may move slightly away from the board, causing contact to be lost. The service center technician can disassemble the device and reconnect the cable.
In more complex cases, it is necessary to replace the sensor module itself or the entire upper cable (where the sensor, speaker and front camera are often located). The cost of such a procedure is usually small compared to replacing the screen.
⚠️ Attention: Do not try to disassemble the phone yourself if you do not have experience. Damage to sealed adhesive joints can lead to loss of moisture protection and further problems with electronics.
Temporary solution for sensor failure
If repair is not possible right now, use an application that locks the screen by pressing the power button or using a timer during a call. It's not ideal, but it will prevent accidental cheek pressure.
Sometimes the problem lies in the deformation of the case. If the phone is curved too much, the distance between the sensor and the protective glass may change, making reading impossible. Visually it is difficult to notice, but the wizard will determine the defect during diagnostics.
⚠️ Attention: Settings interfaces and engineering menu codes may differ depending on the version of Android and the manufacturer’s shell. Always check the official documentation for your specific device model.
Frequently asked questions (FAQ)
Why does the screen go blank when I am holding the phone in my hand, but not during a call?
This indicates that that the sensor is working, but the dialer app does not process its signal correctly. Try clearing the "Phone" application cache in application settings or updating it.
Is it possible to disable the proximity sensor permanently?
There is no standard function for completely disabling it, since this is a critical element. However, there are third-party applications that emulate the operation of the sensor or ignore its signals, but this can lead to inconvenience.
Does a magnetic case affect the operation of the sensor?
Yes, some cases with magnetic clasps or metal inserts may interfere with the operation of the sensors. Try removing the case and checking the phone's operation.
What to do if, after replacing the screen, the sensor stops working?
Most likely, when replacing it, they used non-original glass without a cutout for the sensor or connected the cable incorrectly. You need to contact the service to eliminate the installation error.