Error code
AC6
Meaning
The drum motor controller isn't communicating properly
Critical
What to do
Why this happens
Possible causes include incorrect or disconnected wire connections between the main and inverter PBAs, a fault in the main PBA communication circuit, or a fault in the inverter PBA communication circuit.
How to fix it
This one needs a professional technician to check the internal wiring and motor controller.
SourceSamsung service manual / Customer Repair Guide