LG LSWS305ST Service Manual page 44

CHECKING FLOW CHART BY FAILURE MODE
Oven does not heat (including F-9 error)
Power On
Check the thermistor using the test mode 4.Diagnosis
Oven sensor.
After value the sensor value are 70˚F ~ 90˚F(at 24˚C)
Is the value OK?
Yes
Replace the Relay PCB
2
No
No
Is the value OK?
Yes
No
OK?
Yes
END
Power Off
Check the thermistor's resistor
CN04 pin3, 4
Normal: approximately 1.09 kΩ
5-12
Replace the Sensor
END
Replace the System PCB