F15 means the control board lost track of drum position, usually a loose sensor connector rather than a mechanical failure.
F15 appears when the electronics lose track of the drum’s position. Without that reference, the washer can’t time the wash and spin phases correctly.
The information provided here is a diagnostic aid and does not replace the intervention of a qualified professional.
No cause is certain until it has been checked on the appliance.
An error code varies by brand
The same code can have a different meaning depending on the brand and model. Always check your appliance's manual before acting.
When to call a professional
If the simple checks turned up nothing, if the repair involves electricity, gas, or the sealed refrigerant system, or if you have any doubt at all: stop there and hand the appliance over to a qualified technician.