Error code reference

Maytag Dishwasher Error Code Thermistor failure

Thermistor failure detected during Field Service Test; indicated by Heavy Wash LED flashing along with Clean…

Maytag codesMaytag dishwasher codes

Thermistor failure detected during Field Service Test; indicated by Heavy Wash LED flashing along with Clean LED (front controls) or Delay LED (top & front controls).

First step from the service manual

Run Field Service Test to confirm. Check thermistor resistance (10K ohms ± 3% at 77°F).

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

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What Thermistor failure means on a Maytag dishwasher

The Maytag dishwasher thermistor failure code indicates the control board detected a fault with the thermistor during the Field Service Test cycle. The thermistor is a temperature-sensing resistor located in the wash tub that reports water temperature back to the control board. The fault is confirmed when both the Delay LED and Heavy Wash LED flash simultaneously during the Field Service Test. The control board compares the thermistor's resistance against expected values and flags a failure when readings fall outside the normal range. Expected resistance is 10K ohms at 77°F and 2.4K ohms at 140°F.

For homeowners, the thermistor is a small sensor that tells the dishwasher how hot the water is during a cycle. Your dishwasher relies on this reading to heat water to the correct temperature for washing and sanitizing dishes. When the sensor fails or sends a bad reading, the dishwasher cannot regulate water temperature correctly. This can result in poor cleaning, incomplete drying, or the machine stopping mid-cycle to protect itself. The sensor itself is a relatively small and inexpensive part, but confirming the diagnosis with a resistance test before replacing anything is the right first step.

Source: manufacturer service documentation.

Common causes of Thermistor failure

  1. 01

    Failed thermistor (out-of-range resistance)

    Part replacement

    The thermistor itself has degraded or failed internally, producing resistance values outside the expected range of 10K ohms at 77°F or 2.4K ohms at 140°F. This is the most common cause and is confirmed by testing the component directly with a multimeter.

  2. 02

    Damaged or disconnected wiring harness to thermistor

    Wiring / connection

    The wiring harness connecting the thermistor to the control board may have a broken wire, corroded connector, or loose terminal. This causes an open circuit or erratic resistance reading even if the thermistor itself is functional.

  3. 03

    Corroded or burnt thermistor connector

    Wiring / connection

    Moisture inside the dishwasher can corrode the connector pins at the thermistor or control board end, introducing resistance into the circuit that skews the sensor reading and triggers the fault code.

  4. 04

    Faulty control board

    Part replacement

    If the thermistor and its wiring test within spec, the control board's thermistor input circuit may have failed, causing it to misread or ignore a good signal. This is the least likely cause and should only be considered after the thermistor and wiring are ruled out.

See the test procedure for each cause

Frequently asked questions about Thermistor failure

What does the Thermistor Failure code mean on a Maytag dishwasher?
The Thermistor Failure code means the control board detected a problem with the thermistor, the sensor that monitors water temperature during the wash cycle. The fault is indicated by the Delay LED and Heavy Wash LED flashing together during the Field Service Test. The thermistor should read 10K ohms at 77°F and 2.4K ohms at 140°F. A reading outside these values confirms the sensor or its wiring circuit has a problem.
How do I fix the Thermistor Failure code on my Maytag dishwasher?
Start by entering the Field Service Test mode to confirm the code, then use a multimeter to test the thermistor's resistance directly at the component. Compare your reading against the spec values of 10K ohms at 77°F and 2.4K ohms at 140°F. If the thermistor is out of range, replace it. If it reads correctly, inspect the wiring harness and connectors for damage or corrosion. A professional technician is advisable if the wiring and thermistor both test good, since the next step involves diagnosing the control board.
Can I still use my Maytag dishwasher with the Thermistor Failure code active?
Running the dishwasher with an active thermistor failure is not recommended. Without an accurate temperature reading, the control board cannot properly regulate water heating, which can result in inadequate sanitization, poor wash performance, or the machine stopping partway through a cycle. There is no safety hazard like a fire or flood risk from this specific fault, but continued use will likely produce unsatisfactory results until the sensor is repaired.
How much does it cost to fix a Thermistor Failure on a Maytag dishwasher?
A replacement thermistor is generally an inexpensive part, typically ranging from $15 to $40 depending on the specific Maytag model. If you are comfortable using a multimeter and disconnecting appliance wiring, this is a DIY-friendly repair. If a technician is needed, expect to pay a service call fee plus labor on top of the part cost, which can bring the total to $100 to $200 depending on your area.
How do I test the thermistor on my Maytag dishwasher to confirm the Thermistor Failure code?
Disconnect power to the dishwasher before testing. Locate the thermistor in the wash tub, disconnect its wiring harness, and place your multimeter probes on the thermistor terminals. At room temperature around 77°F, you should read approximately 10K ohms. If the dishwasher was recently run and the tub is warm near 140°F, the reading should drop to approximately 2.4K ohms. A reading of zero, infinite resistance, or a value significantly outside these figures confirms the thermistor has failed and needs replacement.

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