FixByModel
F21

Bosch F21: Motor fault, drum not rotating correctly

The control detected the drum is not turning as expected, or is turning erratically, and stops the cycle. It commonly comes down to worn motor carbon brushes or an obstruction in the drum.

May need a technician

By the FixByModel editorial team · Verified 2026-09 · Researched against manufacturer support & repair references (below)

Most likely causes

  1. Worn motor carbon brushes no longer making good contact (very common on older machines)
  2. Object jammed between the drum and tub blocking rotation
  3. Failed or damaged drive motor
  4. Loose, corroded or damaged motor wiring/connector
  5. Faulty motor control on the main board (less common)
Before you start — unplug the appliance and turn off the water supply. You'll be working near water and electrical parts, and drained water can be hot. If a step involves the pump, wiring, or opening the cabinet and you're unsure, stop and call a qualified technician.

Step-by-step fix

1Power offSwitch off and unplug the washer before checking anything mechanical.
2Spin the drum by handOpen the door and turn the drum by hand; it should rotate freely without grinding or catching.
3Check for obstructionsFeel around the drum edge and lifters for a coin, wire or garment fragment lodged between drum and tub.
4Try a resetRestore power and run a short cycle to see whether the fault was a one-off glitch.
5Have the brushes inspectedIf F21 (E21 on some models) returns, a technician should check the motor carbon brushes and motor windings, replacing the brushes if worn.

Still showing F21?

If you’ve worked through every step and F21 keeps returning, an internal part likely needs testing and replacement. That’s a job for a qualified appliance technician, who can measure the suspect part against the service-manual spec before replacing it.

Which models this applies to

Bosch washing machines. Bosch washers with brushed drive motors and digital fault display; shown as F21 or E21.

FAQ

What does Bosch F21 mean?

Motor fault, drum not rotating correctly. The control detected the drum is not turning as expected, or is turning erratically, and stops the cycle. It commonly comes down to worn motor carbon brushes or an obstruction in the drum.

What causes Bosch F21?

The most likely cause is worn motor carbon brushes no longer making good contact (very common on older machines). Other causes include Object jammed between the drum and tub blocking rotation; Failed or damaged drive motor; Loose, corroded or damaged motor wiring/connector; Faulty motor control on the main board (less common).

Can I fix Bosch F21 myself?

Some checks are DIY, but this code often points to an internal component, so it may need a qualified technician.