Redmi Note 8 Pro screen does not go out when you call: hardware failures or software error?

You've noticed that during a phone call, your Xiaomi Redmi Note 8 Pro screen stays on, even though it used to go off automatically? It's not just an annoying glitch -- the constant backlighting of the display drains the battery 15-20 percent faster, and in some cases signals serious malfunctions. In 80% of cases, the problem is solved software-based, but it's not worth ignoring: prolonged screen operation in call mode can lead to overheating the matrix or failures of the proximity sensor.

In this article, we'll look at all the possible causes, from the usual contamination of the sensor to the hardware damage to the display plume after a fall, which requires the intervention of the service center. You will learn how to diagnose the problem yourself, which settings to check first, and when it's time to carry the phone for repair. For convenience, we have collected step-by-step instructions with screenshots, a table for comparing symptoms and even a survey for owners of the Redmi Note 8 Pro - so you can understand how common your situation is.

1. Approximation sensor: why did it stop working?

The main reason the screen doesn't go out during a call is because the proximity sensor malfunctions, and this tiny sensor is located at the top of the screen (near the speaker) and is responsible for turning off the backlight when you hold the phone to your ear. On the Redmi Note 8 Pro, the sensor is integrated into the front camera module, and it depends on three factors:

• 🔹 Glass pollution: Fat, dust, or protective film can block the infrared signal of the sensor.
• 🔹 Damage after a fall: Even a minor impact can displace the sensor plume or disrupt its contact with the motherboard.
• 🔹 Calibration failure: Sometimes the sensor “forgets” the correct sensitivity values after the update MIUI.

To check the sensor, perform the test in the engineering menu:

1. Open the Phone app and dial ##6484##.
2. Select Proximity Sensor (approximation sensor).
3. Close the sensor with your hand, the value should change from 5.00 to 0.00. If the numbers do not change, the sensor is defective.

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If the engineering menu doesn't open, try the code ##4636## → "Equipment Testing" section.

If the sensor is not responding to cover, but the phone is not damaged, try recalibrating it:

1. Install the Sensor Test app from Google Play.
2. Run the proximity sensor test.
3. Follow the instructions on the screen for calibration (usually you need to hold and withdraw your hand several times).

2. Software failures: Is firmware or applications to blame?

In 30 percent of cases, the screen doesn't go out because of software conflicts.

• 📱 Mistake in MIUI: especially after major updates (e.g., transition from MIUI 12 on MIUI 13).
• 🤖 Google services crash: sometimes Google Play Services will block sensors.
• 📲 Third-party apps: Messengers (such as WhatsApp or Telegram) or call recording programs can intercept screen control.

Start with the simplest thing, which is to reboot your phone. If that doesn't work, follow these steps:

Clear the cache of system applications

Remove newly installed programs

Disable Administrator Rights for Third Party Applications

Reset to factory settings (if other methods did not help)-->

To clear the cache of system applications:

1. Go to Settings → Applications → Application Management.
2. Click on the three dots in the upper right corner and select Show System Processes.
3. Find the Phone, Google Play Services and MIUI System, then click Clear Cache.

If the problem appears after the update, try to roll back to the previous version of MIUI via Fastboot.

1. Download the archive with the right firmware from the Xiaomi Firmware Updater website.
2. Connect your phone to your PC in Fastboot mode (clip Volume Down + Power).
3. Run the script. flash_all.bat archived.

MIUI Update

Installation of a new annex

Phone drop/blows

Self-replacement of the screen

I don't know.-->

3. Phone Settings: What Could Have Changed?

Sometimes the screen doesn't go out because of incorrect settings that the user accidentally or intentionally changed.

Special attention is paid to the special features section, sometimes users accidentally activate functions that interfere with the normal operation of the sensors:

• 👁️ Screen enlargement (Settings) → Special opportunities → Enlargement - can knock down the coordinates of the sensor.
• 🎯 Touch and Hold – Changes the screen response time.
• 🔄 Automatic rotation – if disabled, can block other sensors.

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If you use an informal firmware (like LineageOS or Pixel Experience), the problem may be that there are no drivers for the proximity sensor, in which case only flashing to the official MIUI will help.

Mechanical damage: plume, screen or board?

If the software methods didn't work, it's probably hardware. Redmi Note 8 Pros are the ones that most often fail:

• 📱 Display plume: a thin cable that connects the screen to the motherboard, and if it falls or is not disassembled, it can break.
• 🔌 Approximation sensor connector: oxidized or departs from the board.
• 💥 Power control chips: They're responsible for applying voltage to the screen. When you overheat or short-circuit the screen can stay on permanently.

How to diagnose a hardware malfunction:

1. Check the screen for pressure: gently press the top of the display (where the sensor is located), if the screen starts to go out or flash, the problem is in the plume.
2. Light up with a flashlight: in a dark room, point the light at the sensor. If the screen reacts, the sensor is working, the problem is the software processing of the signal.
3. Connect the external display: through HDMI-Adapter (if supported) If the lights on the outside screen are off normally, the phone's matrix or plume is to blame.

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If the phone fell into water or was in a wet environment, the oxidation of the contacts could disrupt the sensor, in which case only professional cleaning of the board in the service center will help.

Cost of repair of hardware faults:

Conflicts with SIM-map

Rarely, the screen doesn't go out because of a communication module problem.

• 📶 Weak network signal: the phone is constantly trying to reconnect, which interferes with the correct operation of the sensors.
• 🔄 Roaming: in some regions, operators block some of the functions of the phone.
• 📱 Incompatible SIM-card: e.g. eSIM or old-style card (Mini-SIM).

To rule out this cause:

1. Switch from 4G on 3G in network settings (Settings) → SIM-maps and mobile networks → Preferred type of network).
2. Try calling someone else. SIM-map.
3. Turn off VoLTE (Settings) → SIM-map → Voice communication through LTE).

If the screen stops dimming after changing the operator, check the APN settings:

1. Go to Settings. → SIM-map → Access points (APN).
2. Select your operator’s access point or reset your settings to factory ones.

6.Influence of covers and protective glass

You might think that a case could affect the sensor, and in practice, it's easy.

• 📱 Metallized cases shield the proximity sensor signal.
• 🔹 Thick protective glasses (especially those with black bezel) block the infrared sensor.
• 🧲 Magnetic holders (e.g., for mounting in a machine) can magnetize the sensor.

To check the impact of accessories:

1. Remove the cover and the safety glass.
2. Wipe the sensor area with a dry wipe.
3. Call the phone – if the screen goes out, the problem is in the accessories.

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If you use a magnet case (for example, to attach to your hand), try turning it over – sometimes it is enough to change the position of the magnet relative to the sensor.

If you don’t want to give up your favorite cover, try the following solutions:

• 🔧 Cut the hole in front of the proximity sensor (carefully so as not to damage the glass).
• 🔄 Use a cover without metal inserts.
• 📱 Replace the glass with a thinner one (for example, TPU-film).

7. When is it time to bring the phone to the service?

If you've tried all the methods, but the screen still doesn't go out, it's probably a hardware problem.

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Self-repair Redmi Note 8 Pro without experience is fraught with damage to the plume of the display or motherboard. the cost of repair after a failed attempt can grow by 2-3 times.

• ⚠️ Phone fell or got wet.
• ⚠️ The proximity sensor does not respond even after calibration.
• ⚠️ Artifacts appeared on the screen (stripes, flickering).
• ⚠️ The phone overheats during the call.

Before the service visit:

1. Make a backup of the data (Settings → About Phone → Backup).
2. Write down the phone's IMEI (type *#06#).
3. Check if the service center has original parts for the Redmi Note 8 Pro.

The average cost of diagnostics in services is 500-1000 rubles. If the master offers repairs "by photo" without preliminary check, this is a reason to be wary: without a physical examination, it is impossible to determine the exact cause.

FAQ: Frequent questions about the problem

If none of the methods suggested helped, leave a description of your situation in the comments - we will try to help with the diagnosis! Please indicate the version of MIUI, whether there were phone crashes and if you recently changed the firmware.