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Error code reference

GE Dishwasher Error Code F66

Dry heater TCO fault

GE codesGE dishwasher codes

Dry heater TCO fault - temperature out of range.

First step from the service manual

The heater can be purchased as a whole assembly or individual components, except for the thermistor which must be purchased in top housing or whole assembly.

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

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What F66 means on a GE dishwasher

F66 on a GE dishwasher indicates a dry heater fault detected by the control board. The dry heater is the component responsible for heating air during the drying cycle, separate from the wash water heating system. The control board monitors the dry heater circuit for proper electrical continuity and expected resistance values. When it detects an open circuit, a short, or an out-of-range signal from the heater or its wiring harness, it throws F66 and halts the drying function. First place to check is the wiring harness connecting the dry heater to the control board, then the heater element itself.

For homeowners: your dishwasher is telling you the heated drying system has a problem. The dry heater is basically a heating element that blows warm air over your dishes at the end of a wash cycle to dry them. When the dishwasher's electronics tested this heater, something failed the check. Your dishes may come out wet, and the dishwasher may stop mid-cycle. The machine detected this before completing a full drying phase, which is normal protective behavior. The fix usually involves inspecting the wiring connected to the heater or replacing the heater element itself.

Source: manufacturer service documentation.

Common causes of F66

  1. 01

    Damaged or disconnected wiring harness to the dry heater

    Wiring / connection

    The harness connecting the dry heater to the control board can burn, corrode, or work loose over time, breaking the circuit. This is the first thing to inspect per GE's own diagnostic guidance and costs nothing to check before buying parts.

  2. 02

    Failed dry heater element

    Part replacement

    The dry heater element itself can burn out, creating an open circuit that the control board reads as a fault. A failed element will show infinite or no resistance when tested with a multimeter and must be replaced.

  3. 03

    Corroded or damaged harness connector pins

    Wiring / connection

    Even if the wiring harness is intact, the connector pins at the heater or board end can corrode or become damaged, causing intermittent or total loss of continuity. Cleaning or replacing the connector may resolve the fault without replacing the heater itself.

  4. 04

    Faulty control board

    Part replacement

    If the wiring harness and dry heater both test within spec but the F66 code persists, the control board may be misreading the heater circuit. This is the least likely cause but should be considered after ruling out the heater and all wiring.

See the test procedure for each cause

Frequently asked questions about F66

What does the F66 error code mean on a GE dishwasher?
F66 means the control board detected a fault in the dry heater circuit. The dry heater is the component that generates heat specifically for the drying cycle. The board found a problem with electrical continuity or resistance in that circuit, which could be caused by a bad wiring harness connection or a burned-out heater element.
How do I fix the F66 error code on my GE dishwasher?
Start by unplugging the dishwasher and locating the wiring harness that runs to the dry heater, usually accessible by removing the inner door panel. Check for any burned, pinched, or disconnected wires and reseat all connectors. If the harness looks fine, test the dry heater element with a multimeter for continuity. A reading of infinite resistance means the element has failed and needs to be replaced. If both the harness and element test good, the control board may need replacement.
Can I still use my GE dishwasher if it is showing F66?
The dishwasher may still wash dishes, but the heated drying function will not work properly, and the cycle may stop short of completion. Running it repeatedly with an active F66 code is not likely to cause further damage, but your dishes will come out wet. Addressing the fault is recommended before continued regular use, especially since some units may lock out the cycle entirely depending on the model.
How much does it cost to repair F66 on a GE dishwasher?
If only the wiring harness connector needs reseating or cleaning, the repair costs nothing beyond your time. A replacement dry heater element typically runs between $30 and $80 for the part depending on the model. If a technician is needed for diagnosis and replacement, expect $100 to $200 in labor on top of the part cost. A control board replacement is the most expensive scenario, with parts ranging from $100 to $250 plus labor.
Is the F66 code on a GE dishwasher a hard fix or something I can do myself?
Inspecting and reseating the wiring harness is well within DIY range and requires only a screwdriver to remove the inner door panel. Testing the dry heater with a multimeter and replacing the element is also manageable for someone comfortable with basic appliance repair. Control board replacement is more involved but still doable with the correct part and model number. If you are unsure about working with electrical components or the fault returns after replacing the heater, a qualified appliance technician can complete a full diagnosis.

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