E4 error appears and the brushroll will not spin, suction still works

Safety first: Power off the vacuum, remove the battery, and disconnect the motorised floorhead from the wand.

Inspection:

• Check the floorhead for signs of liquid damage (rust, corrosion, water marks). If the floorhead has been used on wet surfaces, it may be unsafe and should be replaced.
• Remove the brushroll and inspect the drive socket and belt (if fitted) for melted plastic or burning smell.
• Check the electrical connector pins on the floorhead and wand for bent pins, corrosion, or burnt marks.
• If you have a multimeter and are competent, test continuity of the brushroll motor windings via the floorhead connector. A dead short or open circuit indicates a failed motor.
• In most cases, the motorised floorhead is replaced as a complete assembly rather than repaired at component level.

Warning: Do not attempt to open the sealed motor compartment of the floorhead unless you are qualified; this can compromise insulation and safety.