F-6 Serious Moderate DIY
LG Microwave F-6 — Cavity temperature sensor short
LG Microwave · Error code F-6
What F-6 Means
The cavity / thermistor circuit is reading shorted (very low resistance). Sensor cooking cycles are blocked; cavity could be over-temperature.
Symptoms
- F-6 on display
- Microwave refuses to start Auto Cook or Sensor cycles
- May trigger after a particularly long bake or convection cycle (on combo models)
Common Causes
1
Shorted thermistor
Sensor element has failed closed.
2
Pinched / shorted sensor wire
Harness chafed against metal cavity and shorted to ground.
3
Water intrusion at sensor plug
Steam condensed in the connector and is bridging pins.
4
Control board input failure
Sensor channel on the PCB has shorted internally.
How to Fix It
- Unplug for 60 seconds and retry — clears transient faults.
- Allow the unit to cool fully if you just ran a long convection / combo cycle.
- Access the thermistor and measure its resistance — a near-zero reading confirms a shorted sensor.
- Inspect the harness for chafing against the cavity or chassis; repair or replace with OEM wire and connectors.
- Dry and reseat the connector at both ends.
- Replace the thermistor if shorted.
- If the sensor and wiring are good, replace the main control board.
Parts You May Need
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
More LG Microwave Codes
Verified against manufacturer documentation: lg.com
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.