How to adjust the proximity sensor on Xiaomi Redmi Note 9 Pro: instructions with photos and tips

The proximity sensor in the Xiaomi Redmi Note 9 Pro is a small but critical element that is responsible for turning off the screen during a phone conversation. When you hold the phone to your ear, the sensor detects the obstacle and extinguishes the display, preventing accidental pressing and saving battery power. However, over time or after software updates, this module can begin to fail: the screen does not go out when you call, accidentally turns off in your pocket or reacts with a delay. In 80% of cases, the problem can be solved independently without visiting the service center.

If you notice that the sensor is not behaving correctly, don’t be quick to blame the hardware. Most often, software settings, glass contamination over the sensor or improper calibration. In this article, we will discuss all the ways to adjust the proximity sensor on the Redmi Note 9 Pro, including hidden engineering menus, test codes and manual sensitivity adjustments. You will learn how to return the phone to normal operation in 10-15 minutes, even if you have previously had no experience in repairing equipment.

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Signs of malfunction of the proximity sensor

Before you start setting up, it is important to make sure that the problem is really related to the sensor, and not to the other components of the smartphone.

• 📵 The screen does not go out during the call, which is why you accidentally press the buttons with your cheek or ear.
• 🔄 The display spontaneously turns off in your pocket or when you hold the phone in your hand (false positives).
• ⏳ Reaction delay: screen goes out 2-3 seconds after being applied to the ear.
• 🔦 Keylighting or notification indicator does not turn off during a conversation.
• 📱 Apps (like Truecaller or WhatsApp) complain about lack of sensor access.

If you know any of these signs, it's likely that the sensor needs calibration, but there are exceptions, such as the Redmi Note 9 Pro with MIUI 13+ firmware, which sometimes has false positives due to optimizing power consumption, in which case it helps to turn off the Adaptive Brightness function in the screen settings.

Also, check if the phone has a protective film or a case with high sides, which can block the infrared signal of the sensor, try to remove the accessories and test the sensor again.

Where is the proximity sensor on the Redmi Note 9 Pro

On the Xiaomi Redmi Note 9 Pro, the proximity sensor is located at the top of the screen, to the right of the speaker. This is a small circular hole (~2 mm in diameter) behind which an infrared sensor hides. To see it, shine a flashlight on the top of the display, the sensor will be slightly different in texture from the rest of the glass.

Important: Don't confuse it with a front camera (centered) or a light sensor (may be left of the speaker), the proximity sensor is always on the right and looks like a small dark spot.

If you plan to clean the sensor, do so carefully: do not use alcohol-containing liquids (they can damage the oleophobic coating of the screen) and avoid rough materials (cotton sticks, toothpicks).

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Before cleaning the sensor, turn off the phone and let it cool down – this will prevent condensation from forming inside the case.

Check the operation of the sensor through the engineering menu

To diagnose the problem accurately, use the hidden engineering menu, which allows you to test the sensor in real time and see its current performance.

1. Open the Phone app.
2. Enter the combination: ##6484### (or #4636## for the alternative menu).
3. Select Proximity Sensor (Proximity Sensor).
4. The screen will show a graph with the numbers 0 (no obstacle) and 1 (there is an obstacle).

Now, run the test:

• 📱 Hold your hand to the top of the screen (where the sensor is located) – the value should change from 0 to 1.
• 🖐️ Remove your hand – the value should go back to 0.
• ⏱️ Repeat the action 3-5 times, observing the reaction rate.

If the numbers don't change or react with a delay, the sensor needs calibration, but if the values jump randomly between 0 and 1 without your intervention, the problem may be in the hardware (for example, the plume has gone away or the sensor is contaminated inside).

⚠️ Note: Not all firmware MIUI Support code ##6484##. If it doesn't work, try an alternative method: install the Sensor Test app from Google Play and check the sensor through it.

Calibration of the proximity sensor without root rights

If the test shows that the sensor is unstable, try software calibration first. On the Redmi Note 9 Pro, you can do this without superuser rights (root) through standard settings or engineering menus.

Method 1: Through the Engineering Menu

Follow the instructions:

1. Open the engineering menu with the code ##6484##.
2. Select Proximity Sensor.
3. Press the Calibrate button.
4. Place your phone on a flat surface and wait until the process is complete (usually 10-20 seconds).
5. Reset the device.

Method 2: Through the MIUI settings

Some versions of MIUI allow you to reset the sensor settings via the menu:

1. Go to Settings → About Phone → MIUI version.
2. Click on the MIUI logo 7-10 times until the notification “You became a developer” appears.
3. Return to the main settings menu and open Additional → for developers.
4. Find the Debugging Sensors item and turn it on.
5. Reboot the phone.

If the sensor still doesn’t work properly after calibration, try resetting the network settings (this sometimes helps in firmware conflicts):

→ SIM-maps and mobile networks → Network reset

Charge your phone at least 50 times%|Remove the cover and film|Close background annexes|Check the operation of the sensor after restarting-->

Manual sensitivity setting of the sensor

On the Redmi Note 9 Pro with custom firmware (such as Pixel Experience or LineageOS) or root rights, you can manually change the sensor’s trigger threshold, which is useful if the sensor is too sensitive (reacts to the pocket) or, conversely, responds poorly to the approach.

For this:

1. Install Sensor Settings from Google Play (requires root).
2. Open the Proximity Sensor section.
3. Find Near Threshold (offset threshold) and Far Threshold (offset threshold).
4. By default, the values are usually 0-5 cm. Try to increase Near Threshold to 7-10 if the sensor does not respond, or reduce to 2-3 if it works too often.
5. Save the settings and restart the phone.

Important: Do not set values below 1 or above 15 - this can lead to complete sensor failure.The optimal range for the Redmi Note 9 Pro is 3-10 cm.

⚠️ Warning: Changing the sensor settings on unofficial firmware can lead to conflicts with system services. If after setting up the phone begins to overheat or discharge quickly, return the standard values and reset the settings.

Hardware causes of malfunction and their elimination

If software methods fail, the problem may be physical damage to the sensor or its contacts, and here are the most common hardware causes and ways to fix them:

• 💧 Even if the phone is not sinking, condensation from a sudden change in temperature (for example, after a bath or rain) can cause contact corrosion. Solution: Put the device in a bag of silica gel for 24 hours.
• 🔌 The plume that's gone, and when you fall or break up your phone, the sensor plume can move away from the motherboard, so you can take the phone apart (or check the service) and check the density of the connection.
• 🧹 Sensor pollution: Dust, sweat, or film glue residue can block the infrared signal. Solution: gently clean the sensor with a soft brush (no alcohol!).
• 🔋 If the sensor doesn't respond at all, its controller may have failed.

For self-diagnosis of hardware problems:

1. Turn off the phone and remove the back cover (if it is removable).
2. Check if the plume running from the top of the screen to the motherboard is moving away.
3. Examine the contacts of the sensor for oxidation (green or white coating).
4. If you see damage, clean the contacts with a wipe or an alcohol wipe (only for experienced users!).

On the Redmi Note 9 Pro, the proximity sensor is integrated into the display module, so its replacement requires a complete disassembly of the phone and the cost of repair in the service can reach 3-5 thousand rubles. If you are not sure of your skills, it is better to contact specialists.

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Before disassembling the phone, be sure to turn off the battery (or wait for it to completely discharge) - this will prevent short circuit.

Frequent errors in sensor adjustment and how to avoid them

Many users make the same mistakes when trying to set up the proximity sensor, which only makes the problem worse.

• 🔨 Use sharp objects to clean the sensor. Toothpicks or needles can scratch the sensor or damage the plume. Use only soft materials.
• 🔥 Heat the phone to dry. A hair dryer or battery can warp the screen or melt the internal components. Dry the phone at room temperature.
• 📲 Install unofficial firmware without backup. MIUI They have sensor bugs. Always back up through Settings. → Additionally. → Backup.
• ⚡ Reset the settings to the factory without checking. If the problem is firmware, reset won't help, but it will delete all your data. Try other methods first.

Also avoid:

• 🧲 Using magnets to “calibrate” a sensor is a myth, the magnetic field does not affect the infrared sensor.
• 🔋 Discharge phone to zero before setting up – this can cause the file system to crash.
• 🛠️ Independent replacement of the sensor without experience - on the Redmi Note 9 Pro, it is soldered to the display module, and careless actions will lead to damage to the screen.

If you doubt your actions, it is better to contact the authorized service center Xiaomi. the cost of diagnosis usually does not exceed 500-1000 rubles, but you will receive a warranty for repair.

FAQ: Answers to Frequent Questions