LG · Microwave Serious

F-A — Cooling fan / motor feedback error

The control isn't getting the expected speed feedback from the cooling fan motor. Magnetron cooling is at risk, so the microwave shuts the cook cycle down.

Keep using it?
Limited use only
DIY difficulty
Hard
Verified against
lg.com ↗

How to fix it

  1. Unplug the microwave.
  2. Remove the cabinet and locate the magnetron cooling fan.
  3. Check that the fan blade spins freely by hand; clean off any grease.
  4. Reseat the fan motor connector at the board.
  5. Apply power briefly and listen for the fan; if it doesn't spin or runs slowly, replace the fan motor.
  6. If the fan runs correctly and harness is good but F-A persists, replace the main control board.

Why it happens

Typical signs: F-A on display · Cook cycle aborts within seconds · Fan may sound slow, loud, or not run at all · Microwave may smell hot if it was running before fault

  • Failed / seized cooling fan motor Bearings worn out from years of grease and heat.
  • Obstructed fan blade Grease buildup or debris jamming the blade.
  • Loose fan motor harness Speed feedback wire disconnected.
  • Main control board fault PCB can't read the tach signal.

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.

  • LG microwave cooling fan motor Common replacement
    Amazon →
  • LG microwave main control board Common replacement
    Amazon →

More LG microwave codes

CH CH / Child Lock — Control locked DOOR DOOR / Door Error — Door switch / interlock fault F-1 F-1 — Main Control Board Fault F-2 F-2 — Keypad / touch panel shorted F-3 F-3 — Key short / specific button stuck F-4 F-4 — Humidity / steam sensor fault

All LG 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: lg.com.