Error code
AC
Meaning
The dryer's internal parts aren't communicating properly
Critical
What to do
Why this happens
Potential issues include a faulty Main PBA (main control board), a defective SUB PBA (display board), or damage/looseness in the wire harness connecting them.
How to fix it
If unplugging and restarting doesn't fix it, the internal wiring or a control board may need attention. This one needs a professional technician.
SourceSamsung service manual / Customer Repair Guide