GE Dishwasher Error Code Wash Boost LED

The Wash Boost LED signals a thermistor error. The control board has detected that the thermistor, a temperature sensor in the wash system, is reading outside its normal resistance range. The board treats a resistance of about 26,500 ohms as an open circuit and about 900 ohms as a short circuit. Either condition means the dishwasher cannot accurately monitor water temperature.

Running the dishwasher with this error active is not recommended for regular use. Without a functioning thermistor, the control board cannot accurately regulate water temperature, which means wash performance will be compromised and any sanitize or high-temperature wash settings will not work reliably. There is no immediate safety hazard in most cases, but continued use without addressing the fault can mask other developing issues.

Disconnect power to the dishwasher, then locate and unplug the thermistor connector. Set a multimeter to measure resistance (ohms) and probe the thermistor terminals. At room temperature, a functioning thermistor should read somewhere between the fault thresholds of 900 ohms and 26,500 ohms, typically in the range of several thousand ohms. A reading at or near those extremes, or an open line with no continuity, confirms the thermistor has failed and needs replacement.

Start by disconnecting power and inspecting the thermistor connector and wiring harness for loose connections, corrosion, or visible damage. Reconnect or clean any corroded terminals and restore power to see if the error clears. If it persists, use a multimeter to test the thermistor's resistance at room temperature. A reading far outside the expected range indicates a failed thermistor that needs replacement. If the thermistor tests correctly, the wiring or control board should be inspected further.

If the thermistor is the cause, the part typically costs between $20 and $60 depending on the model, and a DIY replacement is manageable for someone comfortable with basic appliance repair. Professional labor adds $80 to $150 on average. If the control board is at fault, parts alone can run $150 to $300, making professional diagnosis worthwhile before purchasing a board to confirm that is actually the problem.