Eufy RoboVac Error 4 — Side Brush Motor Fix Guide

What Does This Error Mean?

Error 4 is a side brush jam — the motor is trying to spin and the brush won't turn.
Almost always it's hair wrapped around the spindle right at the base where the brush meets the body.
Pop the brush off, clean the spindle, snap the brush back on.
Three minutes of work clears Error 4 for most users.

Affected Models

Eufy RoboVac 11S
Eufy RoboVac 15C
Eufy RoboVac G30
Eufy RoboVac X8
Eufy RoboVac L70

Common Causes

Hair wrapped around the side brush spindle
Carpet thread tangled at the brush base
Brush bent from repeated wall collisions
Brush not snapped fully onto its spindle
Side brush motor failed (rare)

How to Fix It

Flip the robot.

Find the small spinning brush at the corner of the underside.
Some Eufy models have one, others have two.
Each has three or five soft prongs that radiate out from a central hub.
Pop the brush off the spindle.

On most Eufy RoboVacs, the side brush is held by a small Phillips screw.
Remove the screw and lift the brush off.
If your model is screwless, just pull the brush straight up — it snaps off.
Pull hair off the spindle.

The spindle is the small post the brush sits on.
Hair almost always wraps around it right at the base, where it disappears into the robot body.
Cut the hair free with scissors or pull it off with tweezers.
The spindle should rotate freely under finger pressure.
Inspect the brush.

If the prongs are bent flat, replace the brush — they're a few dollars in two-packs.
A bent brush won't sweep effectively even if it spins.
Eufy sells replacement brushes that match each model.
You can also straighten prongs with a hairdryer (gentle heat re-curls them).
Reinstall and test.

Set the brush on the spindle and screw or snap it back on.
Make sure it's fully seated — a loose brush wobbles and can trigger Error 4 instantly.
Set the robot down and start a cycle.

Frequently Asked Questions

Should I clean both side brushes if my model has two?

Yes.
If one is jammed, the other usually has tangles building up too — they pick up hair at similar rates.
Cleaning both at once means you won't see Error 4 again for the same reason next week.
Same procedure on each, just doubled.

Why does the brush bend so easily?

Side brushes are intentionally soft — they sweep along walls and corners without scratching.
That softness means they bend from collisions over time.
It's normal and expected.
Most users replace side brushes every 6–12 months as they wear out.