Samsung · Washer Moderate

AC — / AC6 — Communication error

The main control board and the sub-PCB (inverter/display) lost communication. Cycle stops because the boards cannot coordinate motor and valve commands.

Keep using it?
Yes, with caution
DIY difficulty
Moderate
Verified against
samsung.com ↗

How to fix it

  1. Unplug the washer for 5 minutes to clear soft errors.
  2. Remove the top panel and reseat every ribbon/connector between the main control and the sub-PCBs (display and inverter).
  3. Inspect harnesses for chafing or burn marks.
  4. If AC returns, swap the inverter PCB (mounted on the motor housing) first — it's the more common failure.
  5. Replace the main control board only if the inverter swap doesn't resolve it.

Why it happens

Typical signs: Cycle stops mid-wash with AC · Display freezes or flickers · May reset for a few cycles then return

  • Loose or corroded harness between PCBs Connector vibrates loose or oxidizes over time.
  • Failed sub-PCB or inverter board One of the linked boards no longer transmits.
  • Main control board failure Less common but possible after voltage surges.

Parts you may need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • Samsung washer inverter PCB Common replacement
    Amazon →

More Samsung washer codes

3C 3C / 3E — Motor Fault 4C 4C / 4E — Water Supply Error 4C2 4C2 — Hot water connected to cold inlet 4E 4E — Water supply error (older code, same as 4C) 5C 5C / 5E / SC — Will Not Drain 5E 5E — Drain error (older code, same as 5C)

All Samsung codes → All washer codes →

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: samsung.com.