Husqvarna Automower Error 021 — Wheel Motor Fix

What Does This Error Mean?

Husqvarna Automower Error 021 indicates a wheel drive motor fault — one of the two rear drive motors has stalled, is drawing excessive current, or is not responding to the control signal. The mower stops and parks in place to prevent damage. Debris jammed in the wheel or a mechanical blockage is the most common cause.

Affected Models

Husqvarna Automower 115H
Husqvarna Automower 315
Husqvarna Automower 430X
Husqvarna Automower 450X
Husqvarna Automower 310 Mark II

Common Causes

Grass clippings, mud, or debris packed tightly around the wheel axle are jamming the motor
A stick, stone, or garden wire has become lodged between the wheel and the chassis
The wheel motor has overheated after extended operation in thick, wet grass
The wheel motor winding has developed an internal fault or the motor driver on the board has failed

How to Fix It

Place the mower on a flat surface and inspect both rear wheels

Turn the mower off using the STOP button (or enter the PIN to disarm it). Flip it onto its back on a flat surface. Spin each rear wheel by hand and feel for resistance. A wheel that is stiff or locks up indicates the jam is on that side.
Clear debris from around the wheel axle and between the wheel and chassis

Use a stiff brush or wooden skewer to clear compacted grass, mud, and debris from around the axle hub and the gap between the wheel and the plastic body. Do not use metal tools near the wiring. After clearing, spin the wheel by hand — it should turn freely with minimal resistance.
Check the wheels and axle for any foreign objects

Inspect closely for wire, string, plant stems, or small stones that may have wrapped around the axle. Fishing line and fine wire can wind tightly around the shaft and are not visible without careful inspection. Remove anything found with needle-nose pliers.
Allow the mower to cool if it was running in heavy conditions

If the mower was mowing thick, wet grass for an extended period, the wheel motor may have tripped a thermal protection cutoff. Place the mower upright in a shaded area for 20–30 minutes before attempting to restart. Error 021 should clear after cooling.
Contact Husqvarna service if Error 021 persists after clearing debris

If both wheels spin freely, the unit has cooled, and Error 021 still appears on restart, the wheel motor or the motor driver circuit on the main board has failed internally. This requires repair at an authorised Husqvarna service centre.

Frequently Asked Questions

Which wheel is causing Error 021 — left or right?

The standard Error 021 display does not indicate which specific wheel has the fault. In the service menu (accessible by a technician with the installer PIN), the fault log shows the specific motor. If you hear or feel one wheel stiff during the hand-spin test, that is the affected side.

How do I prevent wheel motor errors on my Husqvarna Automower?

Reduce Error 021 frequency by cleaning the wheels and axle area after every mow in wet or heavy conditions, raising the cutting height to reduce the density of clippings, and keeping the mowing area free of fallen sticks and wire. Blow out the axle area with compressed air monthly during the mowing season.