Whirlpool · Microwave Serious

F6 — Microwave Relay Failure

The relay that switches the high-voltage transformer / inverter has failed or is being commanded incorrectly. The unit usually won't heat or will heat unexpectedly.

Keep using it?
Limited use only
DIY difficulty
Hard

How to fix it

  1. Stop using the microwave. A welded HV relay is a real safety concern.
  2. Power down at the breaker for at least 1 minute.
  3. If trained on microwave HV: unplug, discharge the HV capacitor, inspect the control board for a burnt relay or scorched PCB trace.
  4. Repair the harness if pinched; otherwise the fix is to replace the appliance control board (the relay isn't typically socketed).
  5. Untrained DIY should call a qualified microwave service tech for F6.

Why it happens

Typical signs: F6 on the display · Microwave fan and light work but no heat · Audible chatter from inside before the code appears

  • Failed power relay on the control board The relay contacts weld or burn open after years of cycling.
  • Shorted wiring to the relay A pinched harness can fault the relay drive circuit.
  • Failed appliance control board When the relay is integral to the board, the whole ACU is replaced.

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.

  • Whirlpool microwave control board Common replacement
    Amazon →

More Whirlpool microwave codes

AccuPop Fail AccuPop Fail — Popcorn Sensor Fault Demo Demo Mode — Not Heating Door Door / Open Door Closed — Safety Reminder F1E4 F1E4 — Appliance Manager or Power Relay Fault F1E5 F1E5 — Inverter Internal Fault F2 F2 — Keypad / Control Fault

All Whirlpool codes → All microwave codes →

Frequently asked questions

What does the F6 code mean on a Whirlpool microwave?

The relay that switches the high-voltage transformer / inverter has failed or is being commanded incorrectly. The unit usually won't heat or will heat unexpectedly.

What causes the F6 code on a Whirlpool microwave?

Failed power relay on the control board: The relay contacts weld or burn open after years of cycling. Shorted wiring to the relay: A pinched harness can fault the relay drive circuit. Failed appliance control board: When the relay is integral to the board, the whole ACU is replaced.

Is it safe to keep using a Whirlpool microwave with a F6 error?

Limited use only. This is rated a serious-severity fault.

How do I fix F6 on a Whirlpool microwave?

Stop using the microwave. A welded HV relay is a real safety concern. Power down at the breaker for at least 1 minute. If trained on microwave HV: unplug, discharge the HV capacitor, inspect the control board for a burnt relay or scorched PCB trace.

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.