LG · Dishwasher
LG Dishwasher FF Error Code
Freeze protection on inlet lines
What this error means
FF indicates Freeze Fault—ambient or inlet water approached freezing and the dishwasher locked out fill to protect valves and hoses.
How FF is detected
When FF appears on a LG dishwasher, the control board has confirmed that water did not leave the machine within the programmed drain window. On LG LDTS5552S, LG LDF5545ST, 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 cabinet area temperature above 40°f. 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
- Dishwasher installed in an unheated garage or vacation home
- Frozen supply line under a cold sink cabinet
- Residual water in inlet valve froze overnight
- Long power outage during sub-freezing weather
Step-by-step fixes
- 1Raise cabinet area temperature above 40°F
- 2Use a hair dryer on low on accessible inlet lines—never open flame
- 3Open under-sink doors to let warm house air reach pipes
- 4After thaw, run hot water at the sink then start a rinse cycle
When to call a technician
FF in a heated kitchen above 50°F suggests a failed freeze sensor or cracked inlet valve body.
Affected models
- LG LDTS5552S
- LG LDF5545ST
- LG LDP6797ST
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use dishwashers 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 dishwasher—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.