Why Xiaomi’s Robot Vacuum Stopped Washing the Floor: A Complete Troubleshooting Guide

Your Xiaomi Mi Robot Mop or Viomi suddenly refused to clean floors, even though it was doing a great job yesterday? This problem is found in 30% of the brand's robot vacuum cleaners, and in 80% of cases it can be fixed on its own without going to a service center, causes ranging from banal clogging of tubes to serious breakdowns of pumps or electronic components.

In this article, we'll look at all the possible reasons why the robot stopped feeding water or spraying it on a napkin, from software failures to mechanical damage, how to check each node of the vacuum cleaner, what errors the system gives when a particular malfunction, and what to do if the robot washes only in one direction or ignores the command to clean it wet, and we've compiled a checklist for quick diagnosis and a spare parts compatibility table for popular models.

We warn you right away: if your vacuum cleaner is warranty, do not disassemble it yourself - this will cancel the warranty obligations. In such cases, it is better to contact the authorized Xiaomi service with an error code (if any).

1. Software failures: when the problem is firmware or settings

In 40 percent of cases, the failure to wash floors is not due to mechanics, but to software errors, which may be due to a failed firmware update, a failure in the Mi Home app, or a miscalculation of cleaning mode. Let's see how to check this.

The first thing you need to do is reboot the robot.

1. Press and hold the power button. ON/OFF 10–15 seconds until you hear the beep.
2. Turn off the vacuum cleaner from the charging station and wait 2-3 minutes.
3. Turn it on again and try to start a wet cleaning.

If the reboot didn’t help, check the settings in the Mi Home app:

• 📱 Update the app to the latest version in the App Store or Google Play.
• 🔄 Reset the app cache in the smartphone settings (section "Apps» → Mi Home → «Warehouse» → «Clear the cache»).
• 🔧 Check cleaning mode: sometimes users accidentally turn off the wash function in task settings. → Settings → Washing mode and make sure the slider is active.

If a robot makes unusual sounds or flashes red when trying to wash, it could indicate a firmware error.

1. Check the version of the software in Settings → About the device → Firmware version.
2. Compare it to the latest available on Xiaomi’s official website.
3. If necessary, update the firmware through the application or manually (instructions below).

2. Clogging of the water supply system: tubes, filters, nozzles

The most common mechanical cause is clogging of water supply, and dust, limestone, or detergent residues can block the flow, causing the robot to either not spray the water at all or to do so unevenly.

First, check the water container:

• 💧 Remove the tank and check if there are any foreign objects inside (hair, thread, pieces of napkin).
• 🧽 Wash the tank with warm water with vinegar (1:1) if you notice lime plaque.
• 🔍 Check the sealing ring on the tank - it should fit tightly, without cracks.

Next, check the tubes and nozzles:

1. Disconnect the water supply hose from the tank (usually it is attached to the latches).
2. Blow the tube with your mouth or compressor – if the air does not pass, then there is a clog.
3. Wash the tube under running water, if necessary, use a thin wire for cleaning.

Pay special attention to the spray unit (nozzles) on the bottom of the vacuum cleaner:

• 🚿 Remove the bottom cover (usually attached to 4-6 screws).
• 🔧 Check the nozzles - they should be clean, without white plaque.
• 💦 Check the mobility of the valve (if you have one in your model), sometimes it sticks due to dirt.

Remove and flush the water tank|

Blow the water supply tube|

Clean the spray nozzle|

Check the sealing ring on the tank|

Refresh the water in the tank (do not use the old one for more than 2 days)-->

If you don't get water after cleaning, it could be the electromagnetic valve or the pump, and that's what we're going to talk about in the next section.

3. Failure of the pump or electromagnetic valve

If the robot is buzzing but the water is not sprayed, or you hear unusual sounds (screaming, clicking) when you try to wash, most likely the pump or electromagnetic valve has failed.

How to check the pump:

1. Remove the bottom cover of the vacuum cleaner (unscrew the screws).
2. Find a pump – this is a small plastic block with tubes, usually located next to the tank.
3. Disconnect the tubes and apply voltage to the pump 5V (You can use a charger from a phone with a cut cable. If it doesn't buzz, it's faulty.

Signs of valve failure:

• 🔊 Clicking without water supply – the valve tries to open but cannot.
• 💧 Constant flow - valve "stick" in the open position.
• ⚡ Mistake. E5 or E6 in the appendix (for Viomi models) V3 newer).

In most cases, the pump or valve will have to be replaced.

The replacement can be done yourself if you have experience with a soldering iron (some models require unsolved contacts).For Xiaomi Mi Robot Mop 2 and Viomi V3 There are detailed video instructions on the Internet with disassembly.

4 Sensor problems: Why the robot can't see water

Modern Xiaomi robot vacuum cleaners are equipped with sensors that monitor water levels, tank position and even wipe moisture. If even one of them fails, the vacuum cleaner may refuse to wash the floor, giving out errors such as: E3, E4 or E9.

What sensors affect washing:

• 💧 The water level sensor detects whether there is fluid in the tank, and if it's contaminated or broken, the robot thinks it's empty.
• 📏 The tank position sensor checks if the container is properly installed, often breaks down after the vacuum cleaner falls.
• 🌡️ Humidity sensor (in models with automatic water supply adjustment) – can block washing if the wipe is too wet.

How to check the sensors:

1. Examine the contacts on the tank and in the vacuum cleaner’s socket – they should be clean, without oxidation.
2. Blow the water level sensor (a small hole next to the tube) and sometimes it gets clogged with dust.
3. Try running a wash without a napkin - if the robot starts spraying water, the problem is the humidity sensor.

If the sensor is faulty, it will have to be replaced. Most Xiaomi models don't have the sensors repaired.

• Water level sensor: 300-500 ₽
• Tanks position sensor: 400-700 ₽
• Humidity sensor: 600–900 ₽ (Only for premium models)

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If the robot makes a mistake E4, But the tank is set up correctly, try to press it down slightly when you start cleaning.

5. Wear or improper installation of the napkin

You'd think what could go wrong with a regular cloth? But the wrong placement of a napkin is one of the top-5 Why the robot refuses to wash. Here's what you need to check:

Common user errors:

• 🧺 Wrap is too thick – blocks sprayers or sensors.
• 🔄 The rag is mounted with the “face” in the wrong direction (some models have the direction of the pile).
• 🧼 Uses a non-original napkin - can not pass water or cling to mechanisms.
• 💦 The napkin is too wet - protection against leaks works.

How to properly install a napkin:

1. Use only original or certified wipes for your model.
2. Make sure the cloth lies flat, without folds and does not close the holes for the sprayers.
3. For models with a vibration module (such as the Xiaomi Mop 2 Pro), check that the wipe does not block moving parts.

If the robot washes in only one direction or leaves stripes, the problem may be:

• 🔄 Wear of the vibration module (replacement required).
• 🧲 Displacement of magnets in a napkin (if it is magnetically fastened).
• 🛠️ Breakdown of the servo drive that turns the napkin.

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If the robot washes in stripes, try changing the napkin for a new one first, and 60 percent of the time, that's how the problem is solved.

Mechanical damage: falls, blows, wear of parts

Xiaomi’s robot vacuum cleaners don’t like falling from a height (like a ladder) or hitting furniture hard, and even if everything looks normal, the internal components could shift or crack.

What to look out for:

• 🚗 Case – cracks in the tank or spray unit can cause water leaks.
• 🔧 If the water is not stained, then the water will not be flowing into the nozzle.
• 🔄 Moving parts - after the impact could jam the servo drive of a napkin or pump.

If the robot fell from a height, be sure to check:

1. Tank tightness - sometimes cracks are almost not visible, but water leaks through them.
2. The gyroscope is capable of “forgetting” the map or moving chaoticly after being struck.
3. Battery condition – Strong vibrations can damage the battery.

In case of mechanical damage, it is better to contact the service, especially if the robot is on warranty.

7. Battery and power problems

If the robot is not charged enough, it can refuse to clean wet to save energy, and battery problems can cause pumps or sensors to malfunction.

Signs of battery problems:

• ⚡ Fast discharge – the robot works for less than 30 minutes.
• 🔋 No charge - after a night on the base shows less than 80%.
• 🚫 Refuses to wash at a charge level below 50%.

How to check the battery:

1. Run a full cleaning with washing at 100% charge.
2. If the robot refuses to wash, but vacuum cleaner - a problem in the settings of energy saving (disable Eco mode in the application).
3. Check the battery voltage with a multimeter (should be 14.4–14.8V most models).

If the battery is worn out (capacity has fallen below 60%), it will have to be replaced. The average cost of the original battery for Xiaomi robot vacuum cleaners is 2,500-4000. ₽.

8.When to contact the service: signs of serious breakdowns

Not all problems can be solved by yourself, but here are the signs that the robot needs professional diagnostics:

• 🔥 Smell of smoke or smoke when trying to wash indicates short circuit.
• 💧 Constant flow of water, even when the robot is turned off - a problem with the valve or pump.
• 🤖 Robot does not respond to buttons and app, but charges - motherboard failure.
• ⚡ Mistakes. E1, E2, E7 — Usually associated with critical faults of sensors or motors.

The average cost of repairs in Xiaomi service centers:

Before the service visit:

1. Take a picture or record a video of the problem.
2. Save the error log from the Mi Home app (Device section) → Journal).
3. Check if the service center has original parts for your model.

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If the robot is warranty, do not open it yourself! The service may refuse to repair under warranty if there are signs of disassembly.

FAQ: Frequent questions about washing problems with Xiaomi robot vacuum cleaners