LG · Washing Machine
LG Washing Machine FF Error Code
Freeze detection or frozen fill lines
What this error means
FF indicates Freeze Fault detection. LG washers in garages or unheated spaces can trigger FF when inlet water or internal lines approach freezing—the machine locks out fill to prevent ice damage to valves and hoses.
How FF is detected
When FF appears on a LG washing machine, the control board has confirmed that water did not leave the machine within the programmed drain window. On LG WM3400CW, LG WT7800CW, and similar variants, the drain pump runs for a fixed interval—often three to seven minutes on washers and dishwashers—while a pressure switch or turbidity sensor verifies the tub or sump is empty. If water remains, the cycle stops to prevent spin with a full tub or overflow on the next fill.
Most FF calls are resolved without parts: raise room temperature above 40°f or relocate the washer to a heated space. Restricted drain paths mimic pump failure because the impeller spins against a blocked hose or filter. Document whether the pump hums audibly during the drain step; a humming pump with no water movement points to a clogged filter or kinked hose, while silence may indicate a failed pump motor or loose wiring at the harness.
After clearing blockages, run a short cycle and listen at the drain hose for steady water flow. If FF returns on the next load with a clean filter and straight hose, measure resistance at the pump motor connector per the service manual for your model before ordering a replacement pump assembly.
Common causes
- Ambient temperature below 32°F in the installation area
- Frozen inlet hoses or wall supply lines
- Residual water in the inlet valve froze overnight
- Washer stored in an unheated space during winter move-in
Step-by-step fixes
- 1Raise room temperature above 40°F or relocate the washer to a heated space
- 2Warm frozen inlet lines with a hair dryer on low—never use open flame
- 3Pour warm (not boiling) water over accessible hose sections until flow returns
- 4After thawing, run a warm fill cycle and confirm FF clears before regular use
When to call a technician
If FF persists in a heated room above 50°F, the freeze sensor or inlet valve may have internal ice damage.
Affected models
- LG WM3400CW
- LG WT7800CW
- LG WM3700HWA
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use washing machines to prevent FF from lint and food debris buildup.
- Record when FF appears in the cycle and whether it clears after a 60-second power reset on your LG washing machine—that detail speeds diagnosis if you call service.
- Keep the model and serial number from the rating plate when ordering parts for FF; LG uses multiple revisions with different harness lengths and board firmware.
- Photograph wiring connector orientation before disconnecting any component while troubleshooting FF; reversed plugs on pumps and valves cause immediate repeat faults.