GE Dishwasher Error Code F51

F51 means the control board has detected a temperature sensor (thermistor) reading that is abnormally low, below the range the board considers valid. This usually points to a shorted thermistor, a damaged wire in the sensor circuit, or a loose connector at the thermistor plug. The machine stops normal operation because it cannot reliably monitor water temperature.

Running the dishwasher with an active F51 is not advisable. Without reliable temperature data, the control board cannot regulate the heating element safely or ensure water reaches sanitizing temperatures. In most cases the machine will halt mid-cycle anyway. Use the dishwasher only after the fault is resolved to avoid potential overheating or incomplete wash results.

Disconnect power to the dishwasher before testing. Locate the thermistor near the sump assembly, unplug its connector, and place multimeter probes across the two thermistor terminals. At room temperature (around 68 to 77 degrees Fahrenheit) a functional GE thermistor should read approximately 40,000 to 60,000 ohms. A reading of zero or near zero ohms indicates an internal short and confirms the thermistor needs to be replaced. An open circuit (infinite resistance) points to a broken wire or open sensor, which would typically trigger a different high-reading fault code.

Start by unplugging the dishwasher and locating the thermistor near the sump at the tub base. Unplug and firmly reseat the thermistor connector, then restore power and run a cycle to see if the code clears. If it returns, test thermistor resistance with a multimeter; a good sensor reads roughly 40,000 to 60,000 ohms at room temperature. A reading near zero indicates a shorted sensor that needs replacement. Also inspect the full wiring run from the sensor to the control board for any pinched or burned spots.

If the fix is simply reseating a connector, there is no parts cost and the repair takes under 30 minutes. A replacement thermistor typically costs between $15 and $40 for the part. If a wiring harness section needs replacement, parts run $20 to $60 depending on the model. A control board, if it comes to that, ranges from $80 to $200. Adding professional labor, expect $100 to $200 for a service call on top of parts costs.