Calibration of the proximity sensor on Xiaomi Redmi Note 9 Pro: full instructions with expert advice

The proximity sensor in the Xiaomi Redmi Note 9 Pro is a small but critical component that automatically shuts down the screen during phone calls. When it doesn’t work properly, you run into annoying problems: the screen goes off on its own, doesn’t respond to touch, or stays active during a call, leading to accidental taps, often due not to hardware breakdowns, but to software errors or miscalibration.

In this article, we will discuss how to self-calibrate the proximity sensor on the Redmi Note 9 Pro without going to the service center. You will learn about the causes of malfunctions, step-by-step adjustment methods (including hidden engineering menus), and how to check the performance of the sensor after calibration, pay special attention to typical user errors that can exacerbate the problem, and give recommendations for prevention.

Why is the proximity sensor on the Redmi Note 9 Pro not working properly?

Before you start calibrating, it's important to understand what caused the malfunction, and 80 percent of the time, the problem is software-based and it's solved without disassembling the device, and here are the main reasons:

• 📱 Firmware failure after update MIUI — New versions of software sometimes conflict with sensor drivers.
• 🔧 Incorrect settings in the engineering menu (for example, after manual adjustment of parameters).
• 🛠️ Mechanical damage: cracks on the glass near the sensor, moisture or dust under the body.
• 🔋 Processor overheating – at high load, sensors can give false positives.
• 📲 Conflict with applications, especially those that request access to sensors (e.g., automation software).

If the sensor stopped working after the phone fell or fluid hit, calibration is unlikely to help — you will need to replace the module. Otherwise, try software methods.

How to check the operability of the proximity sensor?

Before you calibrate the sensor, make sure it is really faulty. Use built-in MIUI tools or third-party apps to do this.

Method 1: Testing through the Engineering Menu

1. Open the Phone app and enter the code: ##6484##.
2. Select Proximity Sensor (Proximity Sensor).
3. Put your hand up to the top of the screen (where the sensor is located), and when you work properly, you will see a change in values from 5 (far) to 0 (close).

Method 2: CPU-Z or Sensor Test

Download one of the apps from Google Play and check the sensor readings in real time. If the values do not change or jump randomly, the sensor needs to be calibrated or replaced.

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If the sensor doesn't respond at all (the value is always 5), try to clean the surface of the sensor with a soft wipe.

Step-by-step instruction: calibration of the proximity sensor

If the test shows that the sensor is unstable, calibrate it. There are two main methods: through the engineering menu and using third-party utilities, and we recommend starting with the first method, since it does not require the installation of additional software.

Method 1: Calibration through the engineering menu

1. Open the Phone app and enter the code: ##6484##.
2. In the engineering menu, select Proximity Sensor.
3. Press the Calibrate button. If it's not there, move on to the next step.
4. Close the sensor with your hand (or a piece of paper) and wait until the value is 0.
5. Remove your hand and make sure the value is back to 5.
6. Reboot the phone.

If the problem persists after the reboot, try the alternative engineering menu code: ##4636# → Testing → Sensors.

Method 2: Calibration with Proximity Sensor Reset

If the engineering menu doesn't work, install Proximity Sensor Reset from Google Play, which automatically resets the sensor settings to factory settings:

1. Open the app and press Reset Proximity Sensor.
2. Confirm the action and wait for the process to be completed.
3. Reset the device.

Manual sensitivity setting of the sensor

In some cases, the sensor works, but it goes too late or too abruptly, and you can fix this by changing the thresholds in the engineering menu.

Instructions:

1. Enter the code ##36446337## (for some versions of MIUI).
2. Go to the Proximity Sensor section.
3. Find Near Delay (delay in approach) and Far Delay (deletion delay).
4. Set the values: Near Delay: 200-300 ms (the smaller, the faster the screen goes out). Far Delay: 500-700 ms (the larger, the longer the screen stays off).

Save the settings and restart the phone.

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Do not install Near Delay less than 100ms – this can cause the screen to permanently shut down even with normal phone use.

Frequent calibration errors and how to avoid them

Many users compound the problem by following questionable advice from the Internet, and here are the most dangerous errors that can make the sensor fail:

• ⚠️ Use of informal firmware. ROM (LineageOS, for example, often don’t have the right drivers for Xiaomi sensors.
• ⚠️ Resetting settings via fastboot without backup.It could erase calibration data forever.
• ⚠️ Cleaning the sensor with alcohol or liquids. Alcohol and moisture damage the infrared sensor.
• ⚠️ Change the persist.sy.proximity settings manually without understanding the consequences.

⚠️ Attention! If after calibration the sensor has stopped responding at all, do not try to repeat the procedure repeatedly. This may indicate a hardware malfunction (for example, a train disconnected.

Another common mistake is ignoring MIUI updates. Xiaomi regularly releases patches to fix sensor bugs. Check for updates in Settings → About Phone → System Update.

Hardware malfunctions: when calibration will not help

If all software methods have been tried, but the sensor is still not working properly, the problem may be in the hardware.

• 🔴 The sensor does not respond to calibration or tests.
• 🔴 The values in the engineering menu are always 0 or 5, regardless of obstacles.
• 🔴 Visible damage: cracks in glass above the sensor, traces of oxidation.
• 🔴 The problem occurred after a phone drop or contact with water.

In such cases, it is required:

1. Diagnosis in the service center (the cost of verification is from 500 rubles).
2. Replacement of the proximity sensor (price of the part + work - 1,500-2,500 rubles).
3. Check the plume connecting the sensor to the motherboard.

⚠️ Attention! Don't try to disassemble the Redmi Note 9 Pro yourself to replace the sensor.The module is soldered to the board, and its replacement requires soldering equipment.Unprofessional repairs can damage other components.

Prevention of problems with the proximity sensor

To avoid repeated failures, follow these guidelines:

• 📵 Use cases without a projection over the sensor. Plastic or metallic linings can block the infrared signal.
• 🚫 Don't install apps to "accelerate" your phone. They often turn off background processes, including sensor drivers.
• 🔄 Update regularly MIUI. In new versions, bugs with sensors are corrected.
• 🛁 Avoid moisture. Even a little humidity can cause the sensor contacts to corrosion.

If you make frequent calls in high humidity (such as outside in rain), wipe the top of the screen with a dry wipe after talking, which will prevent condensation from accumulating inside the case.

FAQ: Frequent questions about the proximity sensor on the Redmi Note 9 Pro