Samsung · Microwave Moderate

C-A0 — Communication Error Between Boards

Loss of serial communication between the main PCB and the display/sub-PCB. Microwave cannot operate.

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

How to fix it

  1. Unplug for 5 minutes.
  2. Open the control area and reseat every connector between the main PCB and the display board.
  3. Inspect harness for damage; replace if questionable.
  4. Swap the display board first (often cheaper), then the main board if the error persists.

Why it happens

Typical signs: C-A0 at power up · Display lit but no response · Beep then lockout

  • Loose interconnect harness Cable between main control and display board not fully seated.
  • Damaged ribbon/harness Pinched during prior service or chewed by rodents.
  • Failed sub-PCB Display board not responding to main board polls.
  • Failed main PCB Main board comms transceiver failed.

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 microwave display board Common replacement
    Amazon →
  • Samsung microwave main control board Common replacement
    Amazon →

More Samsung microwave codes

-dr- -dr- — Door Open (Demo / Reminder) 5E 5E / SE — Touchpad Shorted (Older Spelling) C-21 C-21 — Cavity Over-Temperature C-22 C-22 — Temperature Sensor Error C-A1 C-A1 — Functional Error (Damper / Sensing) C-A2 C-A2 — Humidity Sensor Short Circuit

All Samsung codes → All microwave 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.