Accidental tapping of the screen during a phone conversation is a common problem among owners of Xiaomi Redmi 8 Pro. Even a light touch of the cheek can lead to activation of the speakerphone, switching to another contact or even interruption of the call. Fortunately, Xiaomi smartphones provide a feature to automatically lock the screen when approaching the ear, but by default it can be turned off or work incorrectly.
In this article, you'll find three proven ways to adjust your screen lock during calls, from standard MIUI settings to hidden engineering menu features, and we'll also look at why the function might not work, and give you recommendations for optimizing your proximity sensor, and if you're tired of constantly crashing during conversations, the following instructions will help you fix the problem once and for all.
Why is the screen not locked during the call?
Before we get to the settings, it's important to understand why the crash happened. On the Redmi 8 Pro, the infrared proximity sensor that locks the screen is located next to the front camera, and if it's contaminated, damaged, or disabled by software, the function stops working. Here are the main reasons:
- 🔹 Sensor contamination: Dust, greasy prints, or protective film can block the signal.
- 🔹 Software failure: after the update MIUI sensor settings may be reset.
- 🔹 Disabled feature in settings: some users accidentally deactivate the lock in the call menu.
- 🔹 Sensor damage: After falling or repairing, the sensor may fail.
If the sensor is physically fit, the problem is almost always solved by software, and let's start with the simplest way, which is to check the standard MIUI settings.
Method 1: Enabling lock in call settings
The most obvious but often ignored method is to activate the feature via the phone's menu. On the Redmi 8 Pro, the path to setup may vary depending on the MIUI version, but the overall scheme is as follows:
- Open the phone application (pipe icon).
- Click on the three dots in the top right corner and select Settings.
- Go to the Call Settings section or Additional (depending on the firmware version).
- Find the option to Lock the screen when approaching (may be called the Approach Sensor or Autolock during call).
- Activate the switch and save the changes.
If you don't have one, your version of MIUI is hiding it somewhere else.
Settings → Applications → Application Management → Phone → Permissions → Sensors → Enable “Proximation Sensor”⚠️ Note: On some firmware, this option is reset after the update. MIUI, Check the settings again.
Run the sensor test using ##6484##
Clean the sensor area with an alcohol napkin
Make sure the security glass does not cover the sensor
Reboot your smartphone-->
Method 2: Configure through the engineering menu (for experienced)
If standard settings don't work, you can manually calibrate the proximity sensor through an engineering menu, a method that requires caution, as incorrect changes can disrupt the smartphone.
Instructions for Redmi 8 Pro:
- Open the Phone app and enter the code: ##6484## (if the code doesn't work, try ##3646633###).
- In the engineering menu, select Proximity Sensor.
- Check the current values: Value: should be 0 (if you put your hand to the sensor) and 5 (if you remove your hand). Offset: optimal value is 1-3.
Calibrate
Critical note: if after calibration the sensor stopped responding at all, reset the settings of the engineering menu through Restore Default or restart the phone.
| Parameter | Normal value. | Reason for the deviation |
|---|---|---|
| Value (approaching) | 0 | Sensor is contaminated or faulty |
| Value (lack of object) | 5 | Failure of calibration or software |
| Offset | 1–3 | Incorrect setting in the engineering menu |
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If the engineering menu does not open, try entering the code through the standard Calculator app (enter the sequence of numbers without the characters * and #).
Method 3: Using Third-Party Applications
If the built-in MIUI tools fail, you can use third-party utilities. For example, the Proximity Sensor Reset app (available on Google Play) allows you to reset the sensor settings and force the screen lock to be enabled.
Algorithm of action:
- Install the application and give it access to the Sensors and Phone.
- Run the sensor test: hold your hand to the top of the screen – the indicator should change from green to red.
- If there is no reaction, press Reset Sensor and restart the smartphone.
- Activate Force Screen Lock During Calls.
If none of the methods worked, the proximity sensor may have failed, which would require a diagnostic at a service center, and the average cost of replacing the sensor with a Redmi 8 Pro is between 800 and 1,500 rubles (depending on the region).
💡
Before visiting the service center, back up your data via Settings → Additional → Backup – a complete reset may be required during repairs.
Frequent Mistakes and How to Avoid Them
Many users make the problem worse by doing the wrong thing, and here are the most common mistakes:
- Use of unofficial firmware: Custom versions of MIUI (e.g. Xiaomi.eu or LineageOS) may not work properly with sensors.
- Disable permissions for the Phone app: without access to sensors and microphone, the lock will not work. Check permissions in Settings → Apps → Phone → Permissions.
- Ignoring security updates: MIUI patches often fix sensor bugs. Install all available updates.
Another typical situation is that the user is locking, but the screen still responds to touch, and the reason may be due to gesture settings. For example, if the "Raise to wake up" gesture is activated, they may conflict with the proximity sensor. Turn off unnecessary gestures in Settings → Lock screen → Gestures.