LG Refrigerator dH F (F dH, r dH) Error Code: Defrost Failure

What the code means

LG's support article describes F dH and r dH as a freezer or refrigerator defrosting failure. The refrigerator periodically runs a heater on the evaporator coil to melt off frost, and it shows this code when the compartment doesn't get back to its normal temperature within a certain time after defrosting starts. LG's service manuals for its French-door models (for example LMXS28626 and LFXS26973) list dH as "Poor Defrosting" and name the likely causes as a disconnected temperature fuse, a disconnected heater, a drain jam or a bad heater relay on the control board. The same manuals explain the timing: defrost starts after 7 to 50 hours of compressor run time (4 hours after the fridge is first plugged in or power returns), and it ends when the defrost sensor on the evaporator reaches about 46°F (8°C). If the sensor doesn't reach that temperature within an hour, the control treats defrost as malfunctioning. A drain hole that has frozen shut can also cause the code, because the melted water refreezes on the coil instead of running out to the drain pan. While this code is active, frost keeps building on the coil, so you'll often see weak cooling, a warm fresh-food section or ice on the back wall of the freezer.

Likely causes

• Heavy frost or ice built up on the evaporator coil, often from a door that was left ajar or a torn or loose door gasket letting in humid air
• A drain hole in the freezer or refrigerator compartment blocked with ice, so meltwater refreezes instead of reaching the drain pan
• A failed defrost heater (LG's manuals give about 34 to 42 ohms for a good one)
• A blown temperature fuse (Fuse-M), the safety fuse in the defrost control assembly
• A faulty defrost sensor on the evaporator
• A bad heater relay or other fault on the main control board

Safe DIY checks

1. Check the door gaskets on every door. Close each door on a dollar bill and pull it out; if it slides out with no drag, or the gasket is torn or twisted, the seal is letting in moist air that frosts the coil. LG's service flowchart starts with the gasket for this code.
2. Make sure nothing is keeping a door from closing, such as an overfilled bin, a shelf that's out of place or the fridge leaning forward.
3. Do a full manual defrost, which is LG's own fix for an iced-up coil or frozen drain: move your food to a cooler or spare fridge, unplug the refrigerator and leave the freezer and refrigerator doors wide open. LG says the ice melts in about a day in summer and about three days in winter.
4. Put towels on the floor and keep an eye on the drain pan under the fridge while it melts. Once the ice is gone, the meltwater should run out to the drain pan normally.
5. Plug the refrigerator back in, let it cool down for several hours and see whether the code returns. Defrost won't run again until the compressor has run for about 4 hours, so give it a day or two.
6. If dH F comes back after a complete defrost, LG says to have it checked by a technician, because one of the defrost parts has most likely failed.

Parts that commonly fix it

Always match the part number to your exact model.

Related codes

• CF E LG Refrigerator CF E
• CH E LG Refrigerator CH E
• CL E LG Refrigerator CL E
• FF LG Refrigerator FF
• IF LG Refrigerator IF

All LG codes →

Sources

1. LG USA Support: Troubleshooting an F dH or r dH Error Code (defrosting failure, causes, unplug and leave doors open one day in summer or three days in winter)
2. LG LMXS28626D refrigerator service manual: Defrost Heater Error (dH F) check points and flowchart (door gasket, defrost control part, PCB output; heater 34 to 42 ohms)
3. LG LFXS26973S refrigerator service manual MFL62188073: error code summary (dH Poor Defrosting causes), defrost control assembly, defrost timing and 46°F sensor cutoff