F4 error on a GE air conditioner: A troubleshooting guide from the pros

If your GE air conditioner is displaying an F4 error code, don’t worry: this is a problem that you can fix yourself without the need for a costly service call!

If you find out that you need any replacement parts for your GE AC 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.

Important: The error code information provided in this article may not apply to your specific appliance model. The disassembly information is based on GE PTAC Zoneline models starting with AZ45 and AZ65. 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 F4 error code mean?

The F4 error code usually indicates that one of the indoor thermistors isn’t reading valid temperatures. The valid temperature range for the indoor thermistors is -10°F to 140°F.

The F4 error is designed to alert the user that there’s a problem with indoor temperature sensing, which can prevent the unit from maintaining the desired room temperature.

What you need

• 5/16-inch socket or drive
• 1/4-inch socket or drive
• 4 mm Allen wrench
• Multimeter

Important: The specific tools required may vary depending on the model of your appliance and the type of fasteners used on it. Always consult the user manual or refer to any specific instructions provided by the manufacturer for the recommended tools for your appliance model.

Read more: How to troubleshoot & fix common window air conditioner problems  

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind:

• Always power off and unplug your appliance or switch off the circuit breaker before you attempt any maintenance or replacement work. This keeps you safe by eliminating any risk of electric shock.
• 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 see and access appliance parts.
• Keep your workspace free of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with wet hands. Make sure the work area is completely dry.
• 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.
• Wear insulated work gloves to protect your hands from sharp metal parts and debris.
• 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.
• Always take photos or make a note of wiring terminals or other connections before disconnecting them to make reassembly easier.
• Don’t test live voltage with a multimeter if you’re unfamiliar with how to prevent short-circuiting.

Read more: 8 steps to troubleshoot a window air conditioner that’s running but not cooling

How to troubleshoot your air conditioner

Find out what’s causing the F4 error & how to resolve it with these steps.

1. Disconnect the AC from the power source.
2. Remove the air filter from the front of the unit by pulling it out.
3. Lift up the front cover from the lower corners and pull it straight out to remove it from the clips.
4. Check the thermistor for any damage, debris or blockages that would prevent it from working correctly.
5. Check for any loose wiring connections to the thermistor. Reseat any loose connections that you find. If you find any damage to the thermistor or its housing, replace it.
6. Set a multimeter to resistance mode (Ω).
7. Use the meter probes to check the resistance between the following pins on the J29 connector: Pin 1 and Pin 2 (AIR range: 7k Ohms to 64k Ohms), Pin 3 and Pin 4 (COIL range: 10.5k Ohms to 95k Ohms) and Pin 5 and Pin 6 (OUTLET range: 35k Ohms to 300k Ohms)

If you got any resistance values outside the specified ranges, then you’ll need to replace the thermistor. If everything has passed testing so far and you’re still seeing the F4 error code, replace the control board as a last resort.

Read more: How to Clean Your Air Conditioner the Easy Way   

More information

Thank you for reading! We hope this guide helped you get your GE air conditioner working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos.

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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