Sharp Microwave F2 Error — Humidity Sensor

What Does This Error Mean?

F2 on a Sharp microwave means the humidity sensor used by auto-cook is faulty or coated with grease. Clean the sensor grille inside the cavity. Manual cooking still works — F2 only disables sensor-based auto features.

Affected Models

Sharp R-651ZS
Sharp R-1214
Sharp Carousel R-21LCFS
Sharp SMC2242DS
Sharp R-820JS

Common Causes

Grease and food residue coating the humidity sensor grille
Liquid splashed onto the sensor during cooking
Failed humidity sensor component
Sensor wiring loose at the control board connector

How to Fix It

Verify manual cooking works.

Set a 30-second time-cook on a cup of water. If it heats normally, F2 only affects sensor auto-cook (Popcorn, Reheat, Auto Defrost) and the microwave remains usable for manual cooking.
Locate the humidity sensor.

On Sharp microwaves the humidity sensor is typically a small grille or vent opening on the rear wall or upper rear corner of the cavity. Refer to your model's manual for the exact location.
Clean the sensor area carefully.

Wipe the grille with a barely damp cloth. For stubborn grease, dampen the cloth with 50/50 white vinegar and water. Do not allow liquid to drip into the grille — moisture inside the sensor housing causes its own fault.
Power cycle and test.

Unplug for 5 minutes after cleaning, then restore power. Try an auto-cook function (such as Popcorn). If F2 has cleared, the issue was sensor contamination.

Frequently Asked Questions

Can I keep using my Sharp microwave with F2?

Yes — F2 only disables sensor cooking modes. Manual time-cook works normally. The auto-cook features will resume once the sensor is clean or replaced.

How often should I clean the humidity sensor?

Wipe the sensor grille every 2–3 months in normal use, or after any cooking that produces heavy steam or grease (such as bacon or popcorn that scorched). Routine cleaning prevents F2 from appearing.