How to Fix GE Dishwasher Error Codes F50 and F51

GE dishwashers are designed to wash dishes thoroughly while using less water and energy. These appliances rely on electronic controls and sensors to optimize cleaning performance. The dishwasher monitors water temperature using a thermistor sensor during wash and rinse cycles. If this temperature sensor malfunctions, the dishwasher may display error codes F50 or F51 to indicate the issue. This article provides a detailed guide on troubleshooting and resolving these errors.

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

The information in this article may not apply to your specific appliance model. We recommend consulting your manufacturer’s documentation or contact us with any questions.

What do the error codes mean?

F50 and F51 are error codes related to the temperature sensor on GE dishwashers. Here is what each code signifies:

• F50 – Temperature sensor high – The control board has detected abnormally high resistance from the thermistor sensor, indicating high temperatures. This usually means the thermistor is burnt out in an open state.
• F51 – Temperature sensor low – The control board is detecting lower-than-normal resistance from the thermistor, indicating low temperatures. This typically means the thermistor is shorted or has failed in a closed state.

These error codes mean the control board is unable to accurately monitor water temperature during dishwasher cycles due to a malfunctioning thermistor. When F50 or F51 occurs, the dishwasher may not heat water properly or may end cycles prematurely. Proper troubleshooting and repair are required to restore normal operation.

Causes of the error codes

Here are some common reasons for thermistor failure in GE dishwashers:

• Old age: The epoxy seal around thermistor leads can degrade over time, allowing moisture damage. Thermistors may work for 5-10 years before failing.
• Electrical surges: Power surges from electrical storms, grid issues, etc. can damage sensitive electronic controls. Surges can short or burn out thermistors.
• Physical damage: If wire connections are strained excessively or heat seals crack, the thermistor can fail. Improper dishwasher repairs may lead to physical damage.
• Moisture damage: Small leaks from seals, condensers, or tubs can allow moisture to reach electronic components causing shorts. Evidence of moisture inside the control panel indicates a leak issue.
• Faulty control board: If the thermistor checks out okay, the control board may be providing too much voltage or interpreting readings incorrectly resulting in false error codes.

Where is the thermistor located?

The thermistor temperature sensor is located inside the flood switch assembly mounted in the dishwasher sump. The flood switch prevents overflow by shutting off power to the fill valve if the water level gets too high.

On most GE dishwasher models, the entire flood switch assembly must be accessed from below the dishwasher. The assembly is secured to the base of the sump with two 1/4″ hex head screws. Once removed, the thermistor can be checked or replaced as needed.

Some models have the thermistor incorporated into the turbidity sensor mounted on the side of the sump. Access is from the interior tub after removing racks and spray arms. The turbidity sensor is secured with a twist-lock fitting.

Consult a service manual or diagram for the exact thermistor location if you are unfamiliar with the internal layout of your GE dishwasher. Accessing the sensor requires disassembling internal parts.

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 attempting any maintenance or replacement work. This keeps you safe by preventing any risk of injury from electric shock.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with bare wet hands. Make sure the work area is completely dry.
• Check your user manual to see if there are specific installation or safety instructions for your part or appliance. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 
• If the appliance has recently been used, give it plenty of time for any heating parts to cool down before working on it. 
• Take pictures or make a note of wiring terminals or other connections before disconnecting to prevent any problems with reassembly.
• 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.

Troubleshooting steps 

Follow these steps to diagnose and resolve F50 or F51 errors on your GE dishwasher:

Step 1: Confirm the error code

1. Put the dishwasher into Diagnostic error Code mode to verify if F50 or F51 is displayed. 
2. On models with an LED display, active error codes will flash. On models with a digital display, the code will be shown.
3. Consult the owner’s manual for instructions to activate error code mode on your specific GE model. This will confirm the issue is with the thermistor before continuing troubleshooting.

Step 2: Inspect the thermistor and connections

1. After verifying the error code, disconnect the power and check the thermistor wiring harness. Make sure the connections are intact on both ends. 
2. Look for corrosion, damaged pins, or loose wires. Replace the wiring harness if any defects are found.
3. Also, inspect the thermistor visually. Look for cracks, stripped wires, or other physical damage.
4. The thermistor is typically epoxied into the flood switch assembly. Replace the entire assembly if the damage is severe.
5. Reconnect the wiring harness and restore power after inspecting it. Faulty connections can cause intermittent F50 or F51 codes.

Step 3: Check the thermistor resistance

Use a multimeter to check the resistance of the thermistor. At room temperature, resistance should be around 11-12 k Ohms. Here are approximate resistance values at other temperatures:

• 50°F = 20 k Ohms
• 75°F = 11 k Ohms
• 100°F = 5.8 k Ohms
• 125°F = 3.4 k Ohms
• 150°F = 2.1 k Ohms
• 175°F = 1.3 k Ohms

Compare your readings to these resistance ranges based on water temperature. If resistance is significantly higher than expected, the thermistor may have failed to open causing the F50 overheat code. If resistance is much lower, the thermistor may have shorted resulting in an F51 low temp code.

Step 4: Replace the thermistor or control board

1. If the thermistor checks out okay, replace the main control board which interprets temperature readings. 
2. If the thermistor itself is defective, replace the entire flood switch assembly. Disassembly is not recommended.
3. Use care when working inside the dishwasher and follow precautions in the service manual when testing electrical components.

Step 5: Retest dishwasher operation

After replacing the thermistor or control board, clear the error code history. Run a full cycle to verify normal wash and rinse temperatures. The F50 or F51 code should not return. Proper heating and cycle operation should now be restored.

More information

Thank you for reading! We hope you found this information useful to get your dishwasher working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our thousands of free videos and troubleshooting guides available. If you need replacement parts or some extra help, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, order parts, read our DIY blog, and more.

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