F0 error on a GE microwave: A troubleshooting guide

For all the convenience that microwave ovens provide, they’re also susceptible to malfunctions. 

When this happens on a GE microwave, one of the errors you may see is the F0 code, which likely means there’s a problem with the humidity sensor. 

Let’s take a look at this code and break it down so you can fix your microwave yourself.

If you find out that you need any replacement parts for your GE microwave while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Disclaimer: The error code information provided in this article is based on general service manuals and may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes, and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

What does the F0 error mean?

The F0 display on your GE microwave usually indicates a problem with the humidity sensor inside the microwave oven. 

The humidity sensor is a small plastic part that’s mounted on the outer cavity wall inside the microwave shell. 

The sensor protrudes into the oven cavity so it can detect the interior humidity level as food cooks. If the humidity rises above a safe threshold, the sensor acts as a safety feature by automatically shutting off the microwave’s power, which helps prevent a fire and also protects the internal electronics.

There’s also an electrical connection between the sensor and the microwave’s control board. The control board supplies a low voltage DC bias to the sensor (usually about 5VDC) and interprets the signal from the sensor to determine the humidity reading.

When an F0 message shows up, it means the control board isn’t receiving the correct input from the humidity sensor. Without accurate data from the sensor, the microwave can’t monitor how humid the interior gets so it can adjust the timing and power levels throughout the cooking cycle.

Safety tips

Microwaves contain high-voltage parts and can store voltage even when they’re disconnected from a power source. Please be very careful while working on a microwave’s internal parts to avoid electrocution, which has the potential to cause serious injuries or death.

• Always unplug the microwave before troubleshooting or making repairs.
• Discharge the high-voltage capacitor before working on high-voltage parts to eliminate the risk of electric shock.
• Never attempt to run the microwave while its casing is open or when internal parts are exposed. Always completely reassemble the microwave before testing or using it.
• Never attempt to bypass any microwave safety features.
• With the microwave unplugged, remove the outer case to gain internal access.
• Wear insulated gloves and use insulated tools when testing any parts.
• Check all parts for damage before reassembling and powering up the microwave again.
• If the appliance has recently been used, give it plenty of time to cool down before working on it. 
• Take your time while working to prevent accidents and personal injuries. Rushing is the enemy of precision.
• Work in a well-lit area so you can clearly see and access appliance parts.
• Keep your workspace free of clutter and other obstacles. Keep children and pets away from the work area.
• Check the user manual to see if there are specific installation or safety instructions related to your appliance or replacement part. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause personal injury.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.
• Don’t test live voltage with a multimeter if you’re unfamiliar with how to prevent short-circuiting.

How to troubleshoot the F0 error code

Step 1 – Check the humidity sensor

1. Make sure the microwave is plugged in and turned on. 
2. Press and hold the number pads 7 and 8 at the same time.
3. Check the diagnostic number on the display. Numbers 15-185 are normal and can be checked with a detection test. Continue to step 4 if this is the reading shown. If you see 213 or higher, that means the microwave has a bad sensor, loose or damaged wire, or a bad control board. If you see a number below 6, then there’s a shorted sensor or control board.
4. To perform a detection test, place 1/3 cup of water into the microwave.  
5. Press the vegetable (on JVM1660 models) or popcorn setting (on JVM1650 models). The microwave should start immediately. The control should also beep and then shut off. 
6. Touch the clear/off button. If the microwave didn’t pass this check, replace the humidity sensor. If it does complete this test, continue to the next troubleshooting step.

READ MORE: How To Use A Multimeter To Check Appliance Parts

Step 2 – Inspect the sensor’s connections

If the humidity sensor passed testing, it’s time to check its connections to the control board:

1. Make sure the microwave is still unplugged.
2. Check that the sensor connector is fully and correctly inserted into the control board socket. Adjust it if it’s loose or if you see a gap.
3. Look at the connector pins for damage or any that are missing. If you find any corrosion or damage, you’ll need to replace the assembly.
4. Check the socket to make sure no food, grease, or other debris has obstructed it, since that can cause connectivity issues.

Step 3 – Replace the control board

If the humidity sensor passes testing and the connections are good, the F0 code likely means there’s a processing problem in the microwave’s control board. As a last resort, you can swap out the board for an exact replacement from AppliancePartsPros.com.

How to replace the board:

1. Unplug the microwave.
2. Remove the screws along the trim or back of the microwave’s outer case, then carefully pry it off.
3. Remove any screws holding the old control board in place and disconnect any ribbon cables or wiring harnesses attached to it. Make sure the ribbon cables and wiring aren’t damaged.
4. Install the new control board by fastening any screws and reconnecting any cables that were removed from the old board. 
5. Replace the outer case of the microwave and reinstall any screws that were removed.
6. Plug in and turn on the microwave. 
7. Run a short test cycle with a small bowl of water or food to see if the F0 error disappears.

More information

Thanks for reading! We hope this guide helped you fix the F0 error code on your GE microwave. If you have any other questions or need further assistance, don’t hesitate to call us at 1-877-477-7278 and one of our pros will be happy to help! 

If you need a replacement part, you can visit us at AppliancePartsPros.com. There, you can search and order parts with your model number. Most orders arrive within 2-3 business days. We can also help you troubleshoot common microwave problems here.

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