Robot lawn mower problems and how to fix them

Safety first before any check

Robot mower blades are small but very sharp, and the mower can start on its own schedule. Before any inspection, stop it and make sure it cannot start. On most models that means pressing the stop button, switching off the main power and, where the manual describes it, disabling it with the PIN or app.

Note:Press the stop button and switch the mower off or disable it with the PIN before lifting or cleaning it. Never lift or tip a running robot. Wear gloves when handling blades. Unplug the dock's power supply before working on the station or wire. Do not open the battery compartment unless the manual allows it, and use a dealer for internal repairs.

Common problems at a glance

Use this table to find the most likely cause, then follow the matching section or linked guide. If several symptoms appear together, start with the simplest fix: clean the mower and dock, check the wire or signal, then restart.

Patchy cutting and long tufts

Blunt blades tear grass and leave a pale, ragged finish. Most robots use small pivoting blades that should be changed every few weeks in the growing season, so check them first. Next, clean the underside: wet clippings build up around the disc and stop the blades swinging freely. Use a brush or wooden scraper, never a hose or pressure washer unless the manual allows it.

If the cut is even but the lawn still looks shaggy, the mower may not be running long enough for the area. Rated area figures assume an open lawn, so complex gardens need more hours. Raise the cutting height in hot, dry spells, and keep each cut within the one-third rule; the one-third rule tool shows how to bring long grass down in stages.

1. 1

   Disable the mower and put on gloves.

2. 2

   Turn it over gently on a soft surface as the manual shows.

3. 3

   Brush clippings from the disc, wheels and housing.

4. 4

   Check each blade swings freely; replace blunt or chipped blades with the maker's parts.

5. 5

   Review the schedule and add hours if the lawn is complex.

Docking, charging and boundary faults

If the mower will not dock, will not charge or shows a boundary or loop message, check the simple things first. Is the dock powered, with its indicator light on? Are the charging contacts on the mower and station clean and bright? Is the station on firm, level ground? Our robot mower not charging guide covers these in detail.

On wired systems, a break in the boundary wire is a frequent cause. Spades, edging tools, scarifiers and moles all cut wires. Many docks show a light that changes when the loop is broken, but the pattern varies by model, so check your manual. For Husqvarna owners, our Automower no loop signal guide explains how to trace a break.

Wire-free mowers have their own version of this fault. RTK models need a clear sky view at the reference antenna and across the lawn; a new tree canopy, a moved antenna or a nearby building can cause lost position messages. Camera models can struggle in low light or with poorly defined edges. The how robot mowers navigate article explains the differences.

Getting stuck, slopes and wet ground

A mower that keeps stopping in the same place is telling you about the lawn. Ruts, exposed roots, sunken edges and soft wet patches cause most stuck messages, and slopes near the stated limit get harder when the grass is wet. Our stuck mower guide lists fixes for each, and the slopes guide shows models with higher ratings.

If the lawn is fine but the mower still wanders, clean the wheels, check that the tyres are not worn smooth and confirm the wire is pegged tight to the ground, or that the virtual boundary has not drifted.

When to call a dealer

Some faults are beyond simple checks. Call an authorised dealer or the maker's support line if the mower shows a motor, sensor or battery fault after a restart, if the battery is swollen, hot or leaking, if the mower will not power on after a full charge on a working dock, or if a software update fails. Note the exact message shown in the app or display and when it happens; it helps the dealer diagnose quickly.

Do not guess at codes from forums. Messages and code numbers differ between models and software versions, so use the manual and the maker's support pages for your exact model. If you are choosing a replacement, our best robot lawn mower guide compares current models.

Compare robot lawn mowers →

Frequently asked questions

Why has my robot lawn mower stopped working? Start with power: is the dock lit and the mower switched on and charged? Then clean the contacts and underside, check for a boundary or signal message, and restart. Most faults clear at this stage.

What are common Husqvarna robot lawn mower problems? Owners most often see boundary wire breaks, docking trouble on uneven ground, and stuck messages on wet or rutted lawns. The exact message wording varies by model, so check your manual and a Husqvarna dealer.

How often should I change robot mower blades? Many makers suggest every few weeks in the growing season, sooner on sandy soil or where twigs fall. The manual gives the interval for your model.

Can I repair a robot mower myself? Cleaning, blade changes, wire repairs with proper connectors and dock adjustments are normal owner jobs. Leave battery replacement inside sealed units, motor faults and circuit boards to a dealer.