Miscalibration of the proximity sensor Xiaomi: causes and ways to eliminate

Have you ever seen a situation where, during a call, Xiaomi's screen suddenly goes out, does not respond to touch, or, conversely, remains active in the ear? These are classic symptoms of a malfunction of the proximity sensor - a small but critical sensor responsible for turning off the screen when you bring the phone to your face. If you see the Proximity sensor calibration fail in the device settings, the problem requires an immediate solution: without the sensor working correctly, it becomes not only inconvenient, but sometimes impossible to use the smartphone.

In this article, we will understand why there is an error in calibration of the proximity sensor on Xiaomi, Redmi and smartphones. POCO, What models are most susceptible to this problem (spoiler: it's not just old devices!), and what to do to fix it, from simple software methods to radical hardware interventions. MIUI, which the manufacturer does not advertise, but which can save your sensor without contacting the service.

What is a proximity sensor and how does it work in Xiaomi

A proximity sensor is an infrared sensor located at the top of a smartphone screen, usually next to the front camera, and its primary task is to detect when the phone is close to the ear or face during a conversation to automatically turn off the screen and prevent accidental tapping.

Xiaomi devices use two types of sensors:

• 🔴 Infrared (IR) — It emits invisible light and analyzes the reflected signal, more accurate, but sensitive to pollution.
• 🔵 Capacitive - responds to changes in the electric field, less common in budget models.

When the phone is ringing, the system constantly polls the sensor, if it detects an obstacle 2-5 cm away, the screen goes out. Once the phone is pulled away from the ear, the sensor sends a signal to turn on the display. The calibration fail error means that the sensor cannot be calibrated correctly - that is, determine the basic parameters of the environment (for example, light level or background IR radiation).

Causes of calibration failure of the proximity sensor

Calibration errors rarely occur on their own, usually triggered by specific user actions or hardware defects.

Especially vulnerable are models with a cut-out display (for example, Xiaomi Mi 11 or Redmi Note 10 Pro), where the sensor is located below the screen, in which case even a microcrack on the glass can disrupt its operation. Also, the problem often occurs after unlocking the bootloader or installing custom firmware - informal builds. MIUI They do not always process sensor data correctly.

⚠️ Warning: If the error occurred after the phone fell, do not try to calibrate the sensor programmatically! first check the integrity of the plume - repeated calibration attempts can exacerbate the problem.

How to check the work of the proximity sensor on Xiaomi

Before you start repairing, make sure the sensor is the problem.

1. Open the Phone app and dial the combination: ##6484## (some models run ##4636###).
2. In the test menu, select Proximity Sensor.
3. Raise your hand to the top of the screen – the value should change from 5.0 cm (or similar) to 0.0 cm.
4. If the readings do not change or jump chaotically, the sensor is defective.

An alternative way to do this is to use apps from Google Play, like Sensor Test or Phone Doctor Plus, that show real-world data from all sensors, including proximity.

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If the test shows that the sensor is working, but the screen still does not go out during the call, check the settings in the Settings → Special features → Automatically turn off the screen. Sometimes the function is turned off accidentally.

Methods of correcting calibration error

The solutions depend on the cause of the failure, and let's start with the simplest and safest methods.

Programme recalibration

MIUI has a hidden menu for manually calibrating the sensors.

1. Open the phone app and type in ##284##.
2. Select Proximity Sensor Calibration.
3. Follow the instructions on the screen (usually hold and remove your hand several times).

If this code doesn't work, try ##6484## → Manual Test → Proximity Sensor.

2. Reset sensor settings

Sometimes resetting to factory settings only for sensors (without data loss) helps:

• 📱 Go to Settings. → The phone. → All characteristics.
• 🔧 Press 5 times on the Core (or Version) MIUI), activate the developer mode.
• 🔄 Back to Settings → Additionally. → For developers and find Sensor Reset.

3. Clearing the cache and data of the "Phone" application

Conflicts in the com.android.phone system application can block the sensor from working, to reset it:

1. Open Settings → Applications → Application Management.
2. Find the phone (or communication), press Warehouse.
3. Select Clear Cache and Clear Data (Warning: This Will Delete Call Log!).

4. Update or roll back firmware

If the error occurred after the MIUI update, try:

• 🔄 Reverse to the previous version through Settings → The phone. → Updating the system → Three points. → Select a Service Package.
• 📲 Install the latest stable firmware through the Mi Flash Tool (unlocked bootloader required).

⚠️ Attention: Firmware rollback on models with Dynamic RAM Expansion (e.g. Xiaomi) 12T) This may cause loss of data in virtual memory.Before the procedure, disable this function in the settings.

Hardware repair methods

If the software didn't work, the problem is probably a physical malfunction.

1. Cleaning of the sensor and checking the glass

The infrared sensor is sensitive to contamination, so it can be cleaned.

1. Turn off the phone and carefully remove the protective film (if any).
2. Take a soft brush (for example, for lenses) and brush the dust off the sensor area.
3. If you have severe pollution, use alcohol wipes (no more than 70% alcohol!), but do not press hard.

If there is a crack on the glass above the sensor, it will have to be replaced - even micro-damages distort the IR signal.

2. Check and replacement of the plume

The plume connecting the sensor to the motherboard may become oxidized or rubbed.

• 🔌 The error appears when the phone is tilted.
• 📞 The sensor is working, but with a delay (1-2 seconds).
• 🔄 After the reboot, the problem temporarily disappears.

Diagnostics require disassembling the phone and checking the contacts of the plume with a multimeter. If you are not sure about your skills, you should contact the service - improper disassembly can damage the flexible screen cable.

3. Replacement of the proximity sensor

If the sensor is physically damaged (for example, after falling or getting moisture), it will have to be replaced.

The replacement will require:

• 🛠️ Setting screwdrivers (T3, T5).
• 🔥 Salting station (for models with soldered sensor).
• 🧲 Antistatic bracelet.

Xiaomi models most affected by the problem

Analysis of service centers shows that most often calibration error occurs on the following devices:

• 📱 Redmi Note 8/8 Pro – problems with the sensor plume after 1–2 service.
• 📱 Xiaomi Mi A2/A3 — conflicts after updates (due to "clean" Android).
• 📱 POCO F1 — oxidation of sensor contacts due to overheating.
• 📱 Xiaomi Mi 9/9T — Sensitivity to moisture (even without full water intake).

On newer models (such as Xiaomi 13 or Redmi Note 12), the problem is less common due to improved sensor protection, but it is not excluded from mechanical damage.

Frequent questions and answers