Miele Washer Error Code F4057

Error code F4057 on a Miele washer indicates that the control system is not receiving a signal from the tachogenerator, which is the component responsible for monitoring motor speed and rotation. The tachogenerator is typically integrated with or mounted directly on the drive motor, and it generates an electrical signal proportional to motor shaft speed. This feedback signal is essential for the control board to regulate drum rotation during wash, rinse, and spin cycles. Without this signal, the machine cannot confirm whether the motor is running at the correct speed or running at all, and the cycle is halted to prevent potential mechanical damage.

The most frequent causes of F4057 include a failed tachogenerator, a wiring fault in the signal circuit between the tachogenerator and the control board, or a defective motor that has caused collateral damage to the tacho coil. The tachogenerator itself contains a small coil that generates AC voltage as the motor spins. If this coil becomes open-circuit or shorted, or if the magnet that drives the signal degrades, the output drops to zero and the control board logs F4057. Connector corrosion, broken wire harness leads, or loose terminal connections along the tacho signal path can produce the same result intermittently or permanently.

Diagnosis should begin with a thorough inspection of the wiring harness running from the motor to the motor control board, checking for pinched, chafed, or broken conductors. The tachogenerator coil can be tested for continuity and resistance with a multimeter. If wiring is intact and the tacho coil reads open or out of specification, motor replacement or tachogenerator replacement is typically required. In some cases the motor control board itself may fail to process a valid tacho signal even when the sensor is functional, making board testing a necessary step if other components check out.