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Error code reference

GE Washer Error Code E66

Water Temperature Sensor Open circuit.

GE codesGE washer codes

Water Temperature Sensor Open circuit.

First step from the service manual

Check thermistor, wiring, or control.

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

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What E66 means on a GE washer

Error code E66 on a GE washer indicates an open circuit condition in the water temperature sensor circuit. The water temperature sensor, commonly called a thermistor, is a resistive component that changes its electrical resistance in response to water temperature. The washer's control board reads this resistance to determine water temperature and regulate heating during wash cycles. When the circuit reads as open, it means the board is receiving no signal at all, rather than a resistance value outside the normal range.

An open circuit typically points to a complete break in the electrical path between the thermistor and the control board. This can result from a failed thermistor where the internal element has broken, a wiring harness that has become disconnected, corroded, or physically damaged, or a connector that has pulled loose at either the sensor or the control board end. In some cases, the control board itself may have a failed input circuit that cannot read the sensor signal even when the sensor and wiring are intact.

Diagnosing E66 starts at the thermistor. The sensor should be tested for continuity and resistance using a multimeter. A properly functioning thermistor will show measurable resistance rather than an open (infinite resistance) reading. If the thermistor tests good, the wiring harness between the sensor and the control board should be inspected for breaks, corrosion at connectors, and secure seating. If both the sensor and wiring check out, the control board becomes the likely culprit.

Source: manufacturer service documentation.

Common causes of E66

  1. 01

    Failed water temperature thermistor

    Part replacement

    The thermistor itself has developed an internal break, causing an open circuit reading. Testing the sensor with a multimeter will show infinite resistance rather than a measurable value.

  2. 02

    Disconnected or loose wiring connector

    Wiring / connection

    The connector at the thermistor or at the control board has pulled loose or vibrated free over time. Visually inspecting and reseating the connectors at both ends can resolve this without replacing any parts.

  3. 03

    Damaged wiring harness

    Part replacement

    The wire between the thermistor and the control board may have chafed, corroded, or broken. A continuity test along each wire in the harness will identify an open segment.

  4. 04

    Corroded connector terminals

    Wiring / connection

    Moisture exposure can cause corrosion at the connector pins, increasing resistance to the point of an effective open circuit. Look for green or white oxidation on the metal terminals at the sensor connector.

  5. 05

    Faulty control board

    Part replacement

    If the thermistor and all wiring test correctly, the control board input circuit for the temperature sensor may have failed. This is the least common cause and is typically diagnosed only after ruling out the sensor and wiring.

See the test procedure for each cause

Frequently asked questions about E66

What does E66 mean on a GE washer?
E66 on a GE washer means the control board has detected an open circuit in the water temperature sensor circuit. This means the board is receiving no signal from the thermistor, which is the component that measures water temperature. The cause is typically a failed thermistor, a disconnected wiring connector, or damaged wiring between the sensor and the board.
Can I fix E66 on my GE washer myself?
Many E66 repairs are within reach for a technically inclined DIYer. Start by checking for loose or disconnected connectors at the thermistor and at the control board. If connectors are secure, use a multimeter to test the thermistor for continuity and resistance. Replacing a thermistor is generally a straightforward repair involving unplugging the connector and swapping the sensor.
Is it safe to run my GE washer with an E66 error?
Running the washer while E66 is active is not recommended. Without a functioning temperature sensor, the control board cannot accurately regulate water temperature, which could result in improper wash performance or overheating depending on how the machine defaults. It is best to resolve the error before continuing use.
How much does it cost to repair a GE washer E66 error?
If the fix is simply reseating a connector, there is no parts cost involved. Replacing the thermistor typically costs between $15 and $50 for the part. If the control board requires replacement, parts alone can range from $100 to $300 or more, and professional labor will add to the total.
Will resetting my GE washer clear the E66 error code?
A reset may temporarily clear the E66 code, but the error will return if the underlying fault is still present. Resetting the washer does not repair a broken thermistor, damaged wire, or faulty board. The code should be treated as an indicator to diagnose and fix the root cause rather than simply cleared and ignored.

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