Why Xiaomi Redmi Note 8 Pro is not blocked when calling: 7 reasons and ways to fix

Have you noticed that during a phone call, your Xiaomi Redmi Note 8 Pro screen remains active, even though it used to be automatically locked? This problem is not only annoying, it leads to accidental taps on the screen, quick battery drain and even the risk of interrupting an important call. In 80% of cases, software malfunctions are to blame, but sometimes the root of the problem lies in the hardware components.

In this article, we’ll look at all the possible reasons why your smartphone doesn’t lock your screen when you call, from the trivial settings of the proximity sensor to serious firmware failures. You’ll get step-by-step instructions for diagnosing and troubleshooting, and when to contact the service center.

1. Testing of the proximity sensor: the first step of diagnosis

The proximity sensor is a small sensor next to the front camera that detects when you hold your phone to your ear. If it doesn't work properly, the screen won't lock. On the Redmi Note 8 Pro, this sensor is located to the left of the speaker for conversations (see diagram below).

To check his work:

• 📱 Open the Phone app and dial ##6484## (sensor test code).
• 🔍 In the menu, select Proximity Sensor (approximation sensor).
• 🖐️ Close the sensor with your hand – the value should change from 5.00 to 0.00.
• 🚫 If the numbers don’t change or the sensor isn’t on the list, it’s faulty.

If the sensor doesn't respond, try cleaning the surface with a soft napkin — sometimes dust or protective film will block the signal, and check if the phone has a thick case or glass overlaid the sensor.

⚠️ Attention: On the Redmi Note 8 Pro, the proximity sensor is combined with the light sensor. If the screen is not locked, but also does not automatically adjust the brightness, the problem is precisely this module.

Reset sensor settings and calibration

Sometimes the sensor malfunctions because of improper calibration, and MIUI has a hidden menu to reset the sensor settings.

1. Go to Settings. → The phone.
2. Tap 5 times on the line version of MIUI to activate the developer mode.
3. Back to Settings → Additionally. → For developers.
4. Find the Calibration of the proximity sensor and follow the instructions on the screen.

If this item is missing, try an alternative method:

• 📲 Install the Sensor Test app from Google Play.
• 🔄 In the Proximity section, click Calibrate (calibrate).
• 🔄 Reboot your phone after calibration.

Run the test via ##6484##| Clear the sensor surface | Check the calibration in the developer settings |Install the diagnostic application-->

After the reboot, test the call – if the problem persists, move on to the next step.

3. Software failures: cleaning the cache and resetting settings

Often, the fault is not the sensors themselves, but the system files that control them, and let's start with the safest method, which is to clean the cache:

1. Go to Settings → Applications → Application Management.
2. Select the phone (calling app).
3. Press Warehouse. → Clear the cache.
4. Repeat for the Settings app.

If this does not help, reset your network settings:

• 📶 Settings → SIM-maps and mobile networks → Resetting network settings.
• 🔄 Confirm the action and restart the phone.

⚠️ Warning: Resetting your network settings will delete all stored Wi-Fi passwords and mobile internet settings. Write down important data in advance.

If the problem persists, you will have to resort to a more radical method - reset to factory settings. Before that, be sure to back up the data through Settings → Additional → Backup and Reset.

4. firmware problems: update or rollback

Unstable versions of MIUI often cause sensor failures.

1. Go to Settings → About the phone → System update.
2. If an update is available, install it.
3. After the update, reset the cache via Recovery: 1. Turn off the phone. 2. Press the power button + volume up until the logo appears. 3. Select Wipe Cache Partition → Reboot.

If the problem has occurred since the last update, try to roll back to the previous version of MIUI.

• 📥 Download stable firmware from the official website en.miui.com (choose the version for Redmi Note 8 Pro codenamed begonia).
• 🔧 Install it via Recovery or Fastboot (instructions are available on the forum) 4PDA).

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Before rolling back the firmware, check if the bootloader is blocked on your phone. If so, unlock it through the official Mi Unlock app, otherwise you risk getting a brick.

5. Hardware malfunctions: when you need help from the service

If all software methods have been tried, but the screen is still not locked, the problem may be:

• 🔌 Damaged sensor plume is a common problem after falling or disassembling the phone.
• 💡 Faulty display module – if the screen changed, the wizard could damage the contacts of the sensor.
• 🔋 Bloated battery – it can put pressure on the motherboard and disrupt the work of sensors.
• 📱 Oxidized contacts – if the phone has been exposed to moisture.

It is difficult to diagnose hardware malfunctions on your own, but there are indirect signs:

• 🔍 The proximity sensor is not displayed in the test menu (#6484##).
• 🔄 The problem only appears when the phone is in a certain position (for example, if you press the screen).
• 💥 The phone overheats or discharges quickly even without loading.

⚠️ Warning: If you suspect a hardware malfunction, don't try to disassemble the phone yourself - the Redmi Note 8 Pro has fragile plumes that are easily damaged).

6. Alternative solutions: how to lock the screen manually

While you are looking for a reason or waiting for repairs, you can temporarily lock the screen manually:

• 🔒 During the call, briefly press the power button - the screen will go out.
• 📱 Use gestures: in Settings → Additionally. → Button gestures enable the option Blocking with double touch.
• 🤖 Install the Proximity Sensor Fix app from Google Play – it forcibly locks the screen when you call.

You can also turn off touch buttons during a conversation:

1. Go to Settings → Special Options → Physical buttons.
2. Turn on the option to turn off touch buttons when calling.

These methods do not solve the root of the problem, but will help to avoid accidental pressing.

7.Prevention: How to avoid repeated failures

To prevent the problem from returning after repair or reset, follow these guidelines:

• 🛡️ Install a case without high sides - they can block the sensor.
• 🔄 Regularly (every 2-3 months) clean the cache of system applications.
• 🚫 Avoid installing custom firmware - they often break the work of sensors.
• 📲 Do not use your phone in wet conditions (such as in the bathroom) – this leads to oxidation of contacts.

It is also useful to disable battery optimization for system applications:

1. Go to Settings → Applications → Application Management.
2. Select Phone → Battery → Battery Optimization
3. Set it up without limits.

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If the problem has occurred after the update, don’t rush to reset your phone. First check the forums (such as 4PDA or XDA Developers) for known bugs in your version of MIUI. Often a patch comes out after 1-2 weeks.

Frequently asked questions