Written by
Marcus Lindqvist Appliance Care EditorPublished October 26, 2026
VERIFIED
Error codeF21
ApplianceRange
What a F21 on the display means
The oven control is reporting a steam sensor failure. LG’s help library for cooktops and ranges lists the code that way and attaches it to ranges and ovens in general, with no model series named.
Resetting the unit
The manual offers owners a single remedy, done in three moves:
Find the breaker feeding the range or oven and flip it to off.
Leave the power cut for half a minute.
Flip the breaker to on again and look at the display.
Nothing further is listed for owners to attempt on F21.
If the code is still there
A message that survives the reset is, in LG’s wording, a reason to have the unit serviced.
Related codes
F22 carries the same steam sensor failure wording.
LG range service in San Francisco and the Bay Area
Bay Area owners who need hands-on help with an LG range can reach us at (415) 223-7887. Before dialing, jot down F21, the model number and the reset you already ran. The LG range and oven repair page covers the work.
Model compatibility: LG reuses codes across series and model years, so F21 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 is LG's code for a steam sensor failure on a range or oven.
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.
You submit a request with your appliance model and symptom, we confirm an appointment window, and a technician performs an on-site diagnosis. You then receive a clear estimate and decide whether to proceed before any repair begins.
Yes. We provide an upfront estimate after diagnosis. No parts are ordered or installed until you approve the work, so there are no surprise charges.
Replacement parts are selected for the exact model and confirmed with you before ordering or installation.
Service areas are listed on the Locations page. Contact us with your ZIP code to confirm current coverage for your address.
Ready to get your LG appliance working again?
Book a repair online or call us — clear estimates and approval before any repair work begins.
