Stop using it for now. Carrying on with this fault risks further damage or a leak. Switch it off at the wall until it has been looked at.

What F21 actually means

The drum isn't turning the way the machine expects, so it has stopped the cycle — normally a motor or motor control fault.

F21 is the control board telling you it has asked the motor to turn and hasn't got the response it wanted, either no rotation, jerky pulsing, or the wrong speed. On the older brush-type Bosch, Neff and Siemens motors this most often comes down to worn motor carbon brushes; on newer machines it points at the motor control module or the wiring between board and motor. The machine will usually stop mid-wash with water still in the drum.

What usually causes it

Worn or sticking motor carbon brushes (very common on older Bosch/Neff/Siemens machines)
A loose or damaged connection in the wiring between the control board and the motor
A faulty motor control board
Something jamming the drum so the motor can't turn freely
Motor fault — sparking or intermittent running under load

What you can safely check yourself

Work through these in order. Anything beyond this — panels off, testing parts, anything to do with the wiring — is an engineer's job, and not one to attempt with the machine plugged in.

Turn the machine off at the wall for a minute, then switch back on and try a short cycle — F21 can sometimes latch on after a one-off stall.
Open the door and turn the drum by hand. It should spin freely; if it grinds or won't move, don't run another cycle.
Check nothing has slipped between the drum and the outer tub — an underwired bra or coin can stall the motor.
Make sure the load isn't hugely oversized or a single heavy item; try again with a smaller load.

When to call someone

This one usually needs an engineer once you have tried the checks above. We cover Nottinghamshire, Derbyshire and Leicestershire, and it's £66 including VAT for an engineer to come out and diagnose it — £84 in total if it's repaired on the visit with no parts needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Outside our area? The explanation above still stands — take it to a local engineer and tell them the code. Knowing it saves them time and you money.

Bosch F21 error — washing machine

What F21 actually means

What usually causes it

What you can safely check yourself

When to call someone

Other Bosch washing machine codes

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