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Error code reference

GE Dishwasher Error Code Wash Boost LED

Thermistor error

GE codesGE dishwasher codes

Thermistor error - Control is detecting a short or open circuit at the thermistor (open interpreted as 40°F/26.5K ohms, shorted as 200°F/0.9K ohms).

First step from the service manual

Check thermistor resistance at flood switch; verify not open or shorted.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What Wash Boost LED means on a GE dishwasher

The Wash Boost LED error on a GE dishwasher signals a thermistor fault detected by the control board. The thermistor is a temperature-sensing resistor in the wash system that reports water temperature back to the control. The board interprets an open circuit condition when resistance reads approximately 26,500 ohms (equivalent to 40°F) and a shorted condition when resistance drops to approximately 900 ohms (equivalent to 200°F). Either condition prevents accurate temperature monitoring during the wash cycle.

For homeowners, the thermistor is essentially a small sensor that tells your dishwasher how hot the water is. When the control board sees a reading that falls outside the expected range, either too high or too low, it flags the Wash Boost LED to alert you that something is wrong with that sensor or its wiring. The dishwasher cannot reliably heat water to the correct temperature without a working thermistor, which affects wash and sanitize performance.

The fault can originate from a failed thermistor, damaged wiring between the thermistor and the control board, a loose or corroded connector, or in less common cases, a faulty control board that is misreading a good signal.

Source: manufacturer service documentation.

Common causes of Wash Boost LED

  1. 01

    Failed thermistor

    Part replacement

    The thermistor itself has failed internally, causing its resistance to fall outside the normal operating range. A completely open thermistor reads as 40°F regardless of actual water temperature, while a shorted thermistor reads as 200°F, both triggering the fault.

  2. 02

    Damaged or broken wiring harness to thermistor

    Part replacement

    The wiring between the thermistor and the control board has a break, pinch, or burn that creates an open or short circuit. This produces the same resistance readings as a failed thermistor even when the sensor itself is functional.

  3. 03

    Loose or corroded thermistor connector

    Wiring / connection

    The connector at the thermistor or at the control board has come loose or developed corrosion, introducing high resistance or an intermittent open circuit. This can cause the error to appear inconsistently.

  4. 04

    Faulty control board

    Part replacement

    If the thermistor and wiring both test within correct resistance specifications, the control board itself may be misinterpreting the sensor signal. This is the least likely cause and should only be considered after verifying the thermistor and wiring are good.

See the test procedure for each cause

Frequently asked questions about Wash Boost LED

What does the Wash Boost LED error mean on a GE dishwasher?
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.
How do I fix the Wash Boost LED error on a GE dishwasher?
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.
Can I still use my GE dishwasher when the Wash Boost LED error is active?
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.
How much does it cost to fix the Wash Boost LED error on a GE dishwasher?
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.
How do I test the thermistor on a GE dishwasher showing the Wash Boost LED code?
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.

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