Frigidaire · Washer Moderate

E91 — UI Board / Main Control Communication Error

E91 means the user interface (UI) board and the main control board can't communicate — documented identically across multiple Frigidaire washer tech sheets. It is not corrupted/saved-settings data on the UI board.

Keep using it?
Yes, with caution
DIY difficulty
Hard

How to fix it

  1. Unplug the washer for 5 minutes to reset both boards, then retry.
  2. Open the console and reseat the harness connecting the UI board to the main control board at both ends.
  3. Inspect connector pins for corrosion or damage; clean or repair as needed.
  4. If E91 persists, replace the UI board first (more commonly at fault).
  5. If it's still failing after that, replace the main control board.

Why it happens

Typical signs: E91 on display, or washer unresponsive to controls · Washer won't start · Display may freeze or go blank

  • Loose or damaged wiring harness between the UI board and main control board Most common — the connector backs out from vibration or the harness is damaged.
  • Corroded or oxidized connector pins Interrupts the communication line between the two boards.
  • Failed UI board No longer transmitting on the communication bus.
  • Failed main control board No longer receiving on the communication bus.

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.

  • Frigidaire washer user interface (UI) control board Common replacement
    Amazon →
  • Frigidaire washer main control board Common replacement
    Amazon →

More Frigidaire washer codes

E10 E10 — Water fill problem E11 E11 — Fill time too long E13 E13 — Water leak or air leak in pressure system E20 E20 — Drain pump won't pump out E21 E21 — Slow drain / water remains in tub E23 E23 — Drain pump relay fault on control board

All Frigidaire codes → All washer codes →

Frequently asked questions

What does the E91 code mean on a Frigidaire washer?

E91 means the user interface (UI) board and the main control board can't communicate — documented identically across multiple Frigidaire washer tech sheets. It is not corrupted/saved-settings data on the UI board.

What causes the E91 code on a Frigidaire washer?

Loose or damaged wiring harness between the UI board and main control board: Most common — the connector backs out from vibration or the harness is damaged. Corroded or oxidized connector pins: Interrupts the communication line between the two boards. Failed UI board: No longer transmitting on the communication bus.

Is it safe to keep using a Frigidaire washer with a E91 error?

Yes, with caution. This is rated a moderate-severity fault.

How do I fix E91 on a Frigidaire washer?

Unplug the washer for 5 minutes to reset both boards, then retry. Open the console and reseat the harness connecting the UI board to the main control board at both ends. Inspect connector pins for corrosion or damage; clean or repair as needed.

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