Lock the screen during a call on Android: a complete guide

The active screen of a smartphone during a conversation leads to accidental pressing of the cheek, which is why users unintentionally turn on the speakerphone or drop the call, which directly disrupts the communication process.

The function of automatically locking the display when you bring the phone to your ear is implemented at the hardware level using a special sensor. However, software glitches, incorrect settings, or physical contamination can disrupt the operation of this mechanism. In this article we will take a detailed look at how this process works, how to force the lock and what to do if standard methods do not help.

The principle of operation of the proximity sensor

The main element responsible for turning off the display is proximity sensor. This small sensor is usually located at the top of the smartphone, next to the earpiece and front camera. Its task is to determine the distance between the surface of the screen and a foreign object, in this case - your ear or cheek.

When you bring the phone to your head, the sensor detects a change in infrared radiation or field capacitance. The Android system receives a signal that the object is closer to the critical point and initiates a command to dim the screen. As soon as you remove the phone from your ear, the sensor registers the freeing of space, and the display lights up again, allowing you to see the call interface.

Modern models, such as Samsung Galaxy or Xiaomi Redmi, use different technologies for implementing this sensor. In some cases this is a separate infrared module, in others it is a virtual sensor that works based on data from the front camera and artificial intelligence algorithms. Understanding your sensor type is important for diagnosing problems.

⚠️ Attention: If the screen has a low-quality protective glass or thick film, it may block the infrared sensor, causing the screen to not turn off on time.

Standard settings in the Phone application

Before looking for complex technical solutions, you need to check the basic settings of the calling application itself. In most Android shells, this option is enabled by default, but an accidental crash or system update could change the settings.

To check, go to the application Phone and click on the three dots in the upper right corner to open the menu. Select item Settings, and then find section Incoming calls or Additional settings. This is where the switch responsible for how the screen reacts to proximity is usually hidden.

• 📞 Find the item “Turn off the screen during a call” or “Proximity sensor.”
• 🔘 Make sure that the toggle switch is in the active position (usually blue or green).
• 🔄 If the setting is already enabled, try turning it off, rebooting the phone and turning it on again.

The interface may differ depending on the version of the operating system. On devices with pure Android, the path may look like Settings → Sound and vibration → Additional call settings. Device owners Huawei or Honor should look for the corresponding item in the menu Call management.

Diagnostics and calibration of the sensor

If The settings are fine, but the screen still does not lock, the sensor may need to be calibrated. Over time, the sensor may become lost, especially after the device is dropped or the display module is replaced at a service center. To check functionality, you can use the engineering menu.

Open the dialer application and enter the universal code #0#. On many devices, including Samsung, a diagnostic menu will open. Find the button Proximity Sensor or Sensor. When you raise your hand to the top of the phone, the value should change from 0.0 to 5.0 (or from Far to Near).

Codes to enter the engineering menu (may differ):
#0# - Universal test (Samsung and others)
##4636## — Phone information menu (Stock Android)
##6484## — Xiaomi engineering menu

If the sensor does not respond to hand movements in test mode, the problem is hardware in nature. This could be a loose cable, oxidation of contacts, or physical breakdown of a component. In this case, software methods will not help, and a visit to service will be required.

The influence of third-party applications and themes

Often the cause of incorrect screen operation is third-party apps that intercept call control. Applications for recording calls, caller ID, or improving sound quality may conflict with the standard sensor driver.

Custom themes can also cause the problem. Some visual shells modify system files that control the behavior of the screen during a call. If the problem appeared immediately after installing a new theme or launcher, try temporarily returning the system to the standard view.

Application type	Probability of conflict	Recommended action
Call recording	High	Disable in settings or delete
Caller ID	Medium	Check phone access permissions
Third-party launchers	Low	Return the standard launcher for the test
Antiviruses	Medium	Disable real-time protection

To identify the culprit, try booting your smartphone in safe mode. Only system applications work in this mode. If the screen turns off correctly in safe mode, it means that the problem is caused by one of the applications you installed.

Specifics of different versions of Android

The behavior of the system when locking the screen may differ significantly depending on the version of Android. Starting from Android 10 and above, Google has tightened its security policies, which sometimes leads to restricting third-party applications' access to sensors during a call.

On devices with the shell One UI from Samsung, there is a separate “Random Touches” function, which can work in conjunction with a proximity sensor. If it is set too aggressively, the screen may turn off even without raising it to your ear, for example, when you simply hold the phone in your hand.

Features of Android 13 and 14

In new versions of the system, screen locking algorithms have become more dependent on the gyroscope and accelerometer. If the phone is on the table during a speakerphone call, the screen may go dark if the sensor triggers a false alarm. In such cases, disabling the “Raise to Activate” function helps.

Owners of old devices based on Android 6-8 should pay attention to outdated drivers. Manufacturers often stop supporting such models, and bugs can remain unfixed for years. In this case, the only solution may be to install custom firmware.

Radical methods of solving the problem

If none of the above methods helped, you can try deeper methods of interfering with the system. One such method is to reset network and application settings. This will not delete your personal files, but will return all system settings to factory defaults.

Go to Settings → System → Reset settings. Select item Reset Wi-Fi, mobile data and Bluetooth settings. Sometimes this helps to reconfigure the interaction of communication modules with sensors. You can also try clearing the cache of the “Phone” application through the menu Applications → Phone → Memory → Clear cache.

⚠️ Attention: Before performing a full data reset (Hard Reset), be sure to create a backup copy of all important contacts and photos, as this procedure will delete all information from the device.

As a last resort, if the problem is software and cannot be solved by resetting, you may need to flash the device. However, this step is recommended only for experienced users or authorized service centers, as an error can turn the phone into a brick.

Frequently asked questions (FAQ)

Why does the screen go blank when I just hold the phone in my hand without raising it to my ear?

This may happen due to the sensitivity of the proximity sensor being too high or the poor position of the fingers blocking the sensor. Also check if the “Pocket Mode” function is enabled, which artificially simulates the approach of an object.

Is it possible to completely disable the screen lock during a call?

Yes, in the settings of the “Phone” application you can find the item responsible for the proximity sensor and disable it. However, this is not recommended, as you risk accidentally pressing the reset or microphone button with your cheek.

Does the case affect the operation of the sensor?

Yes, some cases with thick sides or metal inserts in the upper part may block the sensor's operating area. Try removing the case and checking the phone's operation without it.

What to do if the proximity sensor does not work at all after replacing the screen?

Most likely, when replacing the display, a non-original module without a built-in sensor was used or the cable was not connected tightly. It is necessary to contact a service center to check the quality of the installed component.

Does calibration through the engineering menu help forever?

Calibration helps to correct the current sensor performance, but if the problem is caused by physical wear of the component, the effect may be temporary. In such cases, replacement of the part is required.