What E21 means on your Bosch washer
Error code E21 on Bosch washers indicates a drive motor fault. The control board has attempted to run the motor but received no feedback — either the motor isn’t spinning, isn’t reaching the commanded speed, or the tachometer (speed sensor) isn’t providing signals. This is a critical code because the motor is essential for all wash, rinse, and spin operations.
Symptoms
- The drum doesn’t turn at all — no wash agitation and no spin
- The motor makes a humming sound but the drum doesn’t move
- E21 appears shortly after cycle start
- The washer may work intermittently before E21 becomes persistent
Common causes
- Worn carbon brushes — on brush-type motors, the carbon brushes wear down to the point where they can’t make contact with the commutator. This is the most common E21 cause on older models.
- Failed motor — the motor windings short or open, preventing rotation
- Motor control module fault — the inverter or motor controller on the main board fails, sending no power to the motor
- Tachometer failure — the speed sensor on the motor sends no feedback, so the board thinks the motor isn’t running
- Seized drum bearings — worn bearings create enough resistance that the motor can’t turn the drum
Troubleshooting steps you can try
- Check for an overloaded drum — an extremely heavy or unbalanced load can prevent the motor from starting. Remove some items and try again.
- Power reset — unplug for 60 seconds. A false E21 can occur after a power interruption.
- Turn the drum by hand — with the machine off, try spinning the drum manually. If it’s stiff or won’t turn, the bearings may be seized.
When to call a technician
E21 almost always requires professional diagnosis. A technician will test the motor windings, carbon brushes (if applicable), tachometer, and the motor control circuit on the board. Carbon brush replacement is a common and relatively affordable repair. Motor or bearing replacement is more involved. Codes may vary by model generation and series.
Need help? Schedule Bosch Washer repair with a certified technician, or contact our team for a free diagnosis consultation.
