The situation when the smartphone screen remains on during a telephone conversation is familiar to many users. This isn't just an annoyance: having an active display near your ear can lead to accidentally pressing buttons, switching to speakerphone, or even ending a call with your cheek. In the worst case, if the phone is in your pocket, this may cause unintentional actions with the device.
A special one is responsible for automatically turning off the backlight. proximity sensor. This small sensor, usually located on the top of the case next to the earpiece, records the distance to the object. When you hold the phone to your ear, the sensor sends a signal to the system and the screen turns off to save power and prevent false alarms. However, the operation of this mechanism is often disrupted due to software glitches or physical interference.
In this article we will analyze in detail the algorithm of actions to restore the correct operation of the sensor. We will look at both standard system settings and more complex calibration methods through the engineering menu. You will learn how to distinguish a software glitch from a physical breakdown and what accessories can interfere with the operation of your Androidsmartphone.
Checking physical obstacles and accessories
Before delving into deep system settings, it is necessary to exclude trivial physical reasons. The proximity sensor works based on infrared radiation or a capacitive field, and any obstacle in the path of the beam can confuse it. Most often, the culprit of the problem is the protective glass or case.
Poor-quality protective films, especially those with a black border or too thick adhesive layer, can block the sensor's operating area. Even a microscopic layer of dust or grease in the area of the top speaker can distort the readings. Try thoroughly wiping the top of the screen with a soft cloth soaked in an alcohol solution.
You should also pay attention to the design of your case. Some models with high sides or a tight fit may mechanically block the sensor. Remove the case and check the operation of the phone in its “naked” form. If the problem has disappeared, it means that the accessory requires replacement or modification.
- 🧼 Thoroughly clean the area around the top speaker and front camera from dirt.
- 🛡️ Remove the protective glass if it has a black frame or is stuck on skewed.
- 📱 Check the operation without case to prevent mechanical overlap of the sensor.
⚠️ Attention: If you have recently replaced the screen or repaired the case, make sure that the technician has correctly connected the proximity sensor cable. Loose contact is a common cause of malfunction after disassembly.
Try to temporarily remove the protective glass and test the bell. If the screen starts to go dark correctly, replace the glass with a thinner one or a model with a cutout for the sensor.
Basic settings in the phone menu
In some shells Android (for example, older versions of MIUI or EMUI), the sensor control function can be placed in a separate settings menu. Although in pure Android this process is automated, it is worth checking whether the function was accidentally disabled by third-party applications or system failures.
Go to the standard “Phone” application (dialer). Click on the three dots in the corner of the screen or the menu button to go to the Settingssection. Look for items related to “Incoming Calls,” “Gestures,” or “Proximity Sensor.” Some firmware has a checkbox “Turn off screen when approaching”, which needs to be activated.
If you did not find the desired switch in the standard call settings menu, the problem may lie in application permissions. Make sure the Phone app has all the necessary permissions to access your device hardware. Go to Settings → Applications → Phone → Permissions and check if there are any restrictions there.
Sometimes simply restarting the telephony service helps. This does not require rebooting the entire device, but it does update the state of the drivers. Try turning Airplane mode on and off. This action will reconnect the radio modules and can reset the frozen status of the sensor.
Calibration of the proximity sensor through the engineering menu
If physical obstacles are excluded, and the settings are in order, most likely the calibration data of the sensor is lost. The sensor could “remember” incorrect zero or maximum values. To correct the situation, you need to enter the engineering menu and perform manual calibration.
Access to these hidden settings is carried out through a special code in the dialing application. The codes vary depending on the processor manufacturer and phone brand. The most common combinations are presented in the table below.
| Brand / Processor | Login code | Menu section |
|---|---|---|
| Xiaomi / Redmi | ##6484## |
Proximity Sensor |
| Samsung | #0# |
Sensor / Proximity |
| MediaTek (universal) | ##3646633## |
Hardware Testing → Sensor |
| Huawei / Honor | ##2846579## |
ProjectMenu → |
After entering the code, you will be taken to the service menu. Find the section responsible for the proximity sensor (usually called Proximity Sensor). There will be a button Calibration or the opportunity to view the current values (Near and Far). Calibration usually requires covering the sensor with your finger, pressing the calibration button, then removing your finger and pressing the confirm button again.
The process may vary depending on the firmware version. In some cases, you just need to press "Start Calibration" and follow the on-screen instructions: cover the top of the phone with your hand when the message appears, and remove your hand at the next signal. After successful completion, the message will appear Calibration Success.
☑️ Procedure in the engineering menu
⚠️ Attention: Be extremely careful in the engineering menu. Do not change settings in sections whose purpose you do not know (for example, radio module frequencies or display parameters), this may lead to the phone not working.
Using third-party applications for calibration
If access to the engineering menu is closed by the manufacturer (which is often the case on modern models with a locked bootloader) or the codes do not work, you can use specialized software from the store Google Play. There are a number of utilities that can interact with sensors at the system level.
One of the popular solutions is the application Proximity Sensor Reset/Fix. It automatically detects your device model and applies the appropriate script to reset the calibration. The principle of operation is simple: you launch the application, follow the instructions (close the sensor, open), and the app writes new reference values.
There are also applications for testing, for example, Sensor Test or AIDA64. They do not directly calibrate the sensor, but allow you to see its readings in real time. Run the test, move your hand to the top of the screen and see if the status value changes from Far (far) to Near (close). If the values do not change at all, there is a hardware problem.
It is important to understand that third-party applications work with limitations. On new versions Android (11, 12, 13 and higher), access to system drivers is severely limited by Google security policies. Therefore, old methods of resetting through apps may not work on new smartphones.
Why did apps stop working on new Androids?
Starting with Android 10, Google has limited app access to sensor data in the background and direct access to system calibration files without root access. This is done to protect the privacy and stability of the system.
Resetting settings and updating software
Sometimes the reason lies not in the sensor itself, but in a software conflict. An error in the power management system or a malfunction in the shell may be blocking the signal from the sensor. In this case, returning to factory settings or updating the firmware helps.
Before taking radical measures, try simply updating the system. Go to Settings → About phone → System update. Manufacturers often release patches to correct driver errors. If you have custom firmware installed, try reverting to the stock version.
If the update does not help, reset the settings. This will erase all data from your phone, so be sure to back up your contacts and photos. Go to Settings → System → Reset settings → Delete all data. After rebooting, the phone will be as good as new, and software conflicts should disappear.
In rare cases, resetting the network settings helps. This won't affect your personal files, but it will delete saved Wi-Fi passwords and Bluetooth settings. The path to this function usually lies through Settings → System → Reset settings → Reset Wi-Fi, mobile data and Bluetooth settings.
Resetting to factory settings eliminates 90% of software causes of sensor malfunction, but requires first saving important data.
⚠️ Attention: The settings menu interface may differ depending on the phone model and Android version. If you do not find the specified path, use the search in the settings by entering the word “Reset.”
Hardware faults and repairs
If none of the software methods helped, and in testing applications the sensor does not respond to the hand, most likely there is a hardware failure. The proximity sensor is a physical component that can fail.
A common cause is a loose cable. If the phone has been bumped or dropped, the sensor connector may have become loose from the motherboard. In this case, it is necessary to disassemble the device and reconnect the cable. Also, the sensor could simply burn out or oxidize due to moisture.
In some models (for example, old Samsung Galaxy S7 or Edge) the sensor is combined with the front camera or speaker in a single module. Replacing such a unit is more expensive than replacing a separate sensor. Diagnostics at the service center will take a few minutes and will accurately indicate the culprit.
Sometimes the problem is solved by temporarily disabling the sensor through third-party utilities (for example, Proximity Off), which forcefully keep the screen on or off using a timer. This is not a repair, but a “crutch” that allows you to comfortably use the phone before a service visit.
- 💧 Moisture getting inside the case is a common cause of oxidation of the sensor contacts.
- 🔨 Impacts can lead to physical damage to the sensor crystal.
- 🔌 The cable often comes off happens after a poor-quality previous repair.
If the sensor is broken and the repair is delayed, install an application to control the screen using the volume buttons. This will allow you to turn off the screen manually during a call.
Frequently asked questions (FAQ)
Why does the screen go dark when I just hold the phone in my hand without bringing it to my ear?
This is a sign that the sensor is too sensitive or incorrectly calibrated. Try recalibrate the sensor through the engineering menu. Also check if the case is pressing on the top of the screen.
Can a virus or malicious application block the sensor?
Theoretically, yes, if the malware has rights to control the hardware. However, most often the culprit is legitimate flashlight or gesture control apps that conflict with the system. Try booting into safe mode.
Does screen brightness affect the operation of the proximity sensor?
No, brightness does not affect the operation of the sensor itself. However, on very bright screens in sunny weather, it may appear that the screen has not gone completely dark, even though the backlight has been reduced to a minimum. This is an optical illusion.
What to do if the engineering menu does not open using the code?
On many modern smartphones (especially in the USA and Europe), access to the engineering menu via USSD codes is blocked by the operator or manufacturer. In this case, only a calibration application from the Play Market or resetting the settings will help.
Why did the sensor stop working after replacing the screen?
Most likely, during the replacement, a non-original screen without a proximity sensor was used, or the technician forgot to connect the appropriate cable. It is also possible that the sensor may be damaged during careless disassembly.