You started cleaning, but the Xiaomi robot vacuum cleaner suddenly stopped with an error related to the side or main brush? while visually the brush is completely clean, without wound hair and debris. This situation is familiar to many owners of Mi Robot Vacuum, Viomi, Dreame and other brands. The error can manifest as code on the display (for example, 02, 03 or 10), flashing an indicator or voice alert about blocking the brush.
In 80% of cases, the problem is not due to physical blockage – sensors, software failures or mechanical problems are to blame. In this article, we will discuss all possible causes of brush error when a clean working organ, including rare cases (for example, bearing wear or cable damage). You will receive step-by-step instructions for diagnostics and repairs with your own hands, and also learn when you can not do without a service center. D9 viomi V3, where brush error occurs most often.
Why does Xiaomi’s robot vacuum cleaner show brush error if it’s clean?
The error with code 02 (side brush) or 03 (main brush) in Xiaomi is not only triggered by a blockage.
- 🔄 Firmware failure: After a software update or reset, the control module misinterprets sensor data.
- 🔌 Contact problems: Oxidation or contamination of brush connectors or control boards.
- 🛠️ Mechanical wear: Luft shaft brush, wear gear gear gear gear gear gear gears or bearings (relevant for models older than 2 years).
- 📡 Interference from other devices: Rarely, but it happens that the error is provoked by radio interference from the router or smart lamps at a frequency of 2.4 GHz.
- 🔋 Insufficient voltage: A discharged battery or a faulty power supply can cause false protections.
In models with a laser rangefinder (for example, Xiaomi Mi Robot Vacuum-Mop P), brush error sometimes appears after a fall or impact - this is due to the displacement of the Hall sensor, which is responsible for controlling the rotation.
First steps: what to do before disassembling the vacuum cleaner
Before you disassemble the device, follow the basic steps that solve the problem in 60% of cases:
- Reboot: Hold the power button for 10-15 seconds until it is completely turned off, then turn the robot on again.
- Contact cleaning: Drink the metal contacts on the brush and in the robot’s socket (use a cotton swab).
- Checking fastener: Remove and set the brush back - sometimes the contacts do not reach the stop.
- Test without brush: Run cleaning without side brush (if the error is related to it) If the robot is working, the problem is in the brush or its connector.
If the error persists, check the Mi Home or DreameHome app logs. The Cleanup log section may include a fault code (e.g., the fault code, error_0x0203), For models with voice assistants, ask the robot to say, "Brush state," which sometimes reveals hidden errors.
☑️ Quick diagnosis of brush error
Diagnostics of the Hall sensor and control board
The Hall sensor is a magnetic sensor that tracks the rotation of the brush, and if it fails or shifts, the robot thinks the brush is locked, to check it:
- Remove the main brush and find a small black sensor next to the shaft (usually mounted on a plastic holder).
- Blow on the sensor or gently clean it with a brush - sometimes it is enough to remove the dust.
- Check the magnet on the shaft of the brush: it should be whole and tightly fixed.
If the sensor is visually correct, but the error remains, the problem may be in the control board.
- 🔍 Check the soldered contacts of the sensor on the board - whether there are cracks or cold soldering.
- 🔌 Measure the multimeter voltage on the sensor connector (should be) ~3.3V or ~5V model-wise).
- 📱 Update your firmware through the app – sometimes bugs are fixed in new versions of the software.
In the Dreame D9 and Viomi V3 models, the Hall sensor often fails due to overheating. If the robot has been working at maximum power for a long time, let it cool for 30 to 40 minutes before retesting.
How to check the Hall sensor with a multimeter?
Mechanical malfunctions: gears, bearings, cables
If the software methods didn't work, look at the mechanical part.
| Malfunction | Signs. | How to eliminate |
|---|---|---|
| Wear of gears of gear gear gears | The brush turns jerky or does not rotate at all, you can hear the grinding. | Replace the gearbox (the item depends on the model, for example, MDY4029GL for Mi Robot 1S) |
| Luft shaft brushes | The brush is wobbling, a knock is heard as it spins. | Replace or replace the shaft with bearings |
| Damage to flexible cable | The error occurs when the brush is in a certain position (for example, when turning) | Call the cable with a multimeter, at a cliff - replace |
| Bearing clogging | The brush is rotating tightly, the whistle is heard | Disassemble the brush, clean and lubricate the bearings (use silicone lubricant) |
The brush will require a T6/T8 cross screwdriver and a plastic mediator to disassemble. In Xiaomi Mi Mi Robot Vacuum-Mop 2 Pro models, the main brush is attached to the latches - be careful not to break them. If you find a black powder around the gears, this is a sign of critical wear and tear, requiring a full replacement of the gearbox.
💡
Before disassembly, take a picture of the location of the gears and wires - this will help to properly assemble the mechanism back.
Software failures: reset, firmware, calibration
A brush error can be caused by calibration failure or firmware damage.
- Reset: Go to Settings → General → Reset (in the Mi Home app). Once reset, the robot will reset and recalibrate the sensors.
- Manual calibration: For models with a laser navigator (such as the Dreame Z10 Pro) after reset, calibration is required. Place the robot on a flat surface and hold the Spot Clean button for 5 seconds.
- Download the latest version of the software from the official Xiaomi website and update the robot through the USB-drive (instructions for your model are in the section "Support").
If the bug persists after the update, check the firmware region. Xiaomi robots purchased in China may conflict with European servers, in which case you need to change the region through the engineering menu (for power users).
💡
Resetting removes all stored room maps. Before the procedure, back up the app if your model supports it.
When can you not do without a service center?
Please contact the service if:
- ⚡ After all the manipulations, the error remains, and the brush does not rotate even manually.
- 🔥 There was a smell of burning or smoke from the body of the robot.
- 💧 On the control board, traces of oxidation or combustible elements are visible.
- 🔄 The robot is not switched on or constantly restarted.
The cost of repair in official Xiaomi services:
- Replacement of Hall's sensor: ~1 500–2 500 ₽.
- Management board repair: ~3 000–5 000 ₽.
- Replacement of the brush reducer: ~2 000–3 500 ₽.
For models over 3 years old, it is sometimes cheaper to buy a new brush or robot than to repair an old one. ~1 200 ₽, A complete repair with replacement gearbox and sensors can cost 6000-8000 ₽.
💡
Before you visit the service, write down the serial number of the robot (located on the bottom) and the firmware version, which will speed up the diagnosis.
Prevention: How to avoid brushing errors in the future
To minimize the risk of repeated failures:
- Clean your brushes after each cleaning – even small hairs can wind up on the shaft and damage the sensor.
- Use original parts – non-original brushes often have incompatible magnets or gear shapes.
- Avoid cleaning wet surfaces – getting water on the Hall sensor leads to corrosion.
- Update your firmware regularly, but not immediately after release – wait for feedback on the stability of the version.
For models with a floor wash function (Xiaomi Mi Robot Vacuum-Mop P), after cleaning, wipe the area around the brush with a dry cloth - this will prevent contact oxidation. It is also recommended to lubricate the brush bearings with silicone lubrication once every 3 months (do not use WD-40 or litol!).