Written by
Maya Chen Editorial TeamPublished October 20, 2026
Error codeF21 error
ApplianceRange
Quick answer
F21 is LG's code for a steam sensor failure on a range or oven. Reset steps from the manual and when to call for service.
Model compatibility: LG reuses codes across series and model years, so F21 error may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
F21 indicates a steam sensor failure.
F21 means steam sensor failure, according to the LG help library for cooktops and ranges.
About the F21 display
The owner’s manual describes F21 as a steam sensor failure. Nothing in the manual ties this one to a particular model line, only to ranges and ovens.
First moves
Switch the breaker serving the unit to off for 30 seconds before turning it back on; LG lists nothing else for owners to try with F21.
If nothing changes, the unit requires service in LG’s words.
Los Angeles owners can call (310) 742-8008 for LG range service. Tell us the code (F21), the model number and what you tried. LG range repair has more.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your LG appliance?
Book a specialist visit for a clear estimate and approval before any repair.
