F3
Daewoo Temperature Sensor Short / Open (Alternate Code)

Microwave shows F3 and will not start, often after a power surge

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Shorted cavity thermistor, Open thermistor circuit, Damaged sensor wiring, Faulty control PCB sensor input

How to Fix / Troubleshooting

Safety first: Unplug the microwave before opening the cabinet.

Step-by-step:

  • 1. Power reset: Unplug for 10 minutes and retry. If F3 returns, proceed to sensor checks.
  • 2. Locate thermistor: Remove the outer cabinet and find the cavity thermistor attached to the cavity wall or air duct.
  • 3. Inspect wiring: Look for signs of heat damage, pinched wires, or loose connectors. Repair or replace damaged wiring.
  • 4. Measure resistance: Disconnect the thermistor and measure its resistance at room temperature. Compare with Daewoo specifications. Replace if readings are out of range or if the sensor is open/shorted.
  • 5. Control board: If a known-good thermistor does not clear F3, the control PCB may be defective and require replacement.
Advertisements

Repair Difficulty

Hard 4/5

Required Part

Cavity Thermistor
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements