Siemens Washing Machine F21 Error Code: Motor Failure and Solutions
2026-11-04
Why Does the Siemens Washing Machine F21 Error Code Occur?
Although Siemens washing machines are built to high engineering standards, they occasionally alert users with various error codes. One of the most common is the F21 error code, indicating that the machine’s motor is not functioning or its speed cannot be controlled. This error usually appears in the middle of the wash cycle or during spin, meaning the machine’s drum cannot rotate.
Primary Causes of the F21 Error Code
When you encounter the F21 code, you might suspect an electrical or mechanical issue with the motor. Here are the main factors that trigger this error:
- Carbon Brush Wear: Carbon brushes on washing machine motors wear down over time due to friction. When they become too short, contact with the motor is lost, triggering an error.
- Tacho Generator Fault: A loose or damaged tacho generator, which measures motor speed, prevents the control board from regulating the motor.
- Control Board Issues: A resistor or circuit burn on the electronic board that manages the motor can block signal delivery to the motor.
- Wiring Faults: Oxidation or disconnections in the cables between the motor and the main board can trigger the error code.
Step-by-Step F21 Troubleshooting and Resolution Process
If you see the F21 error on your machine, there are several basic steps you can take before calling a technician. Just remember that electrical work requires caution.
1. Try Resetting the Machine
Sometimes the electronic board may throw an error due to a temporary voltage fluctuation. To reset your machine, follow these steps: Move the program button to the 'Off' position. Then select the 'Spin' program and, while holding the 'Speed' button, turn the program knob 30 degrees. Wait a few seconds, then move the knob back to 'Off'. This process can clear the machine's memory.
2. Inspect the Carbon Brushes
If resetting didn't help, checking the motor brushes is the most effective approach. Remove the motor from the machine and examine the length of the carbon rods. If they are shorter than 1 cm, replacement is mandatory. A new brush set usually permanently resolves the F21 issue.
3. Examine the Connections
Open the machine’s rear panel and inspect the cables leading to the motor sockets. Look for discoloration at the ends caused by moisture or humidity. If there's a lack of contact, cleaning with a contact cleaner spray can solve the problem.
When Should You Call for Service?
If your brushes are in good condition and no wiring issue is apparent, the fault is most likely on the main board. Repairing the electronic board requires professional equipment and expertise. In such cases, attempting DIY fixes could damage other components. Our recommendation is to seek assistance from an authorized or trusted service technician if the problem originates from the board.
Tips to Prevent the Fault
To extend the life of your washing machine’s motor and avoid F21 and similar errors, pay attention to the following:
- Don't overload the machine beyond its capacity. Overloading strains the motor.
- Using low‑quality or excessive detergent accelerates limescale buildup, making the motor work harder.
- Prevent dust accumulation on the motor by having annual preventive maintenance.
The Siemens washing machine F21 fault can be easily resolved when properly diagnosed. However, remember that safety is paramount.