What does the F3 code mean? It means the control board thinks the sensor has failed open, meaning no continuity (technically above 2,900Ω at the control board).
The Basics
Disconnect Power
As with almost any error code, resetting the device is a good first step. For GE ovens, the easiest way to do this is to disconnect the power.
- You may be able to reach the plug on gas or electric ranges or stoves. You can disconnect the power at the circuit breaker if it is difficult to reach.
- Built-in ovens (like wall ovens) require you to disconnect power at the circuit breaker since they are usually hardwired and don't have a plug.
- Leave the power disconnected for 5 minutes.
- Reconnect the power and check to see if the error returns.
- If it does, move on to the next item. If not, monitor the oven, as this type of error often starts with occasional error codes and then grows in frequency.
Evaluate the Error
When does the error show up? Knowing what cycle is running when the error is displayed and what error is displayed can provide important clues.
- Does the error occur when the oven is idle?
- This points to a bad sensor that has failed.
- Does the error occur after the oven has been used for some time?
- This suggests a sensor that is no longer in spec as far as room temperature resistance or there is a bad connection in the sensor circuit. The extra resistance of the bad connection or the defective sensor causes the sensor to exceed the maximum resistance after it heats.
- Does the error occur in a self-clean cycle or afterward?
- This suggests a sensor showing an overly high resistance or a problem with the door sensor. The control board varies the maximum resistance it will allow based on whether it senses that the door is latched or not. The oven may display a code if the door sensor has a problem when a self-clean is in progress.
- Does the error occur with displays of other errors and shifts between them? This is especially significant when the F2, F3, and F5 errors are displayed. This often suggests a bad Electronic Range Control (ERC). You should check the sensor, but if it tests good, it is almost certainly the ERC.
Defective Temperature Sensor
Get a multimeter and measure the sensor resistance. At room temperature, it should be about 1100 Ω. For more details, see More About Oven Temperature Sensors below.
- Shut off power to the unit before checking this resistance
- Disconnect the sensor so you can measure it directly.
- Replace the sensor if it reads more than 1150Ω or less than 1050Ω.
When checking the sensor's resistance, check for continuity between each sensor lead and the sensor's shell or mounting plate.
- There should be no continuity; if there is, replace the sensor.
- If the sensor checks out, reconnect it, then move to the next step.
Defective Temperature Sensor Wiring Harness
If the sensor is giving correct resistance values at room temperature, then the next step is to check if what the control board is "seeing" is correct. Because the resistance changes are relatively small, a bad connector or crimp can add enough resistance to cause an error message.
- You will want to trace the wire from the sensor to the connectors on the control board and then use your meter to check the resistance in the circuit at the control board.
- As you trace the wire, make sure it is in good condition. If you find any melted insulation or pinched wires, repair them. Make sure you use wire with insulation that matches what you found and porcelain or ceramic wire nuts.
- Disconnect the connectors for the temperature sensor wires at the control board and check the resistance.
- Check the connectors on the control board for corrosion. They should be very clean.
- Check any other connectors or splices in the circuit for any corrosion or burns.
- Some have been known to fail over time, so unplug them and check them. If they have failed, you may have to substitute porcelain or ceramic wire nuts for them.
The control board will regard values below 900Ω as a short.
The control board will regard values above 2900Ω as an open.
Knowing this, you can see how a corroded or oxidized connection could cause the control board to believe the sensor is showing an open.
The special plastic connectors supplied with the sensor will often fail over time. Also, the porcelain wine nuts used instead of the plastic connectors can be a problem. Reinstall them to make sure the connection is tight. You might even want to re-strip the wire so you have a fresh portion for the connection.
If the values check out, go to the next step.
Defective Electronic Range Control (ERC)
At this point, the only thing to replace is the ERC. They can see a fair amount of heat, and some have to be cooled by a fan that draws air across them. If the fan fails, the board can fail.
More About Oven Temperature Sensors
The oven temperature sensor is what is called a resistive temperature device or RTD. They use a coiled length of platinum wire which changes in resistance with temperature. Unlike a thermistor, the resistance of an RTD changes essentially linearly with temperature, with a resistance increase of approximately 2Ω/°F
- In some instances the sensor can fail by losing its linear character. You should, if possible, check the sensor at another temperature to see if it is acting as it should. Since these sensors are essentially identical from oven to oven, you can check them at other temperatures for correct values.
- For higher temperatures, you may be able to use a toaster oven or an electric hot plate. A digital kitchen thermometer can be used to verify the sensor's actual temperature or an infrared thermometer can be used.
- 32°F (0°C) — 1000Ω
- 77°F (25°C) — 1100Ω
- 250°F (121°C) — 1450Ω
- 350°F (177°C) — 1650Ω
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