LG · Oven
LG Oven F3 Error Code
Oven temperature sensor shorted
What this error means
F3 indicates the oven temperature sensor circuit reads shorted to ground. The board sees invalid low resistance and disables heat to prevent runaway temperature.
How F3 is detected
When F3 appears on a LG oven, the control board has confirmed that water did not leave the machine within the programmed drain window. On LG LRG4113ST, LG LREL6325F, 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 F3 calls are resolved without parts: turn off breaker before touching sensor wires. 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 F3 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
- Sensor wire pinched against oven cavity metal
- Shorted RTD probe from grease fire damage
- Moisture bridge after steam cleaning before dry-out
- Harness chafe at the door hinge area
Step-by-step fixes
- 1Turn off breaker before touching sensor wires
- 2Disconnect sensor at the board and measure ohms—should be ~1080Ω at room temperature, not near zero
- 3Inspect harness along the upper oven cavity
- 4Allow 24 hours dry time if steam moisture triggered F3 once
When to call a technician
Replace sensor and harness if short persists with sensor unplugged from the probe side.
Affected models
- LG LRG4113ST
- LG LREL6325F
- LG LDG4313ST
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use ovens to prevent F3 from lint and food debris buildup.
- Record when F3 appears in the cycle and whether it clears after a 60-second power reset on your LG oven—that detail speeds diagnosis if you call service.
- Keep the model and serial number from the rating plate when ordering parts for F3; LG uses multiple revisions with different harness lengths and board firmware.
- Photograph wiring connector orientation before disconnecting any component while troubleshooting F3; reversed plugs on pumps and valves cause immediate repeat faults.