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Dishwasher Temperature sensor (thermistor): What It Does and Signs It's Failing

A small sensor mounted low in the machine, in or near the sump, that tells the control how hot the wash water is. On many Whirlpool-built machines (KitchenAid included) it comes as one part with the OWI, the optical water indicator that reads how cloudy the water is to judge how dirty the load was.

How it works

A thermistor's electrical resistance changes with temperature, and the board turns that into a reading. The control uses it to decide when to stop heating, and the OWI reading helps it judge how much washing the load needs.

Signs it is failing

• A sensor or thermistor error code
• Water stays cool, or the heater runs much longer than normal
• A heating code showing up alongside the sensor code
• Cycles that seem to stall at the same point

Thermistor, soil sensor and some heating codes lead here. Brands often lump the sensor and its wiring together in one code, and Sears PartsDirect says to check the harness between the board and the sensor before replacing the sensor.

Can you replace it yourself?

Shut the breaker off for 30 seconds and see if the code comes back; Whirlpool lists that as the first step. The sensor plugs into the sump or pump assembly under the tub and needs the machine pulled out, so most owners hand this one to a tech.

Buying the right part

Sensors differ by model even inside one brand, and a combined thermistor/OWI part won't swap with a plain thermistor. Look it up by the model number on the tub-edge label.

Error codes linked to the temperature sensor (thermistor)

• C7Temperature sensor circuit faultGE
• F3E2Thermistor or OWI sensor faultKitchenAid
• HEWater not heating properlyLG
• tETemperature sensor problemLG
• F1 / F2Water temperature sensor faultMiele
• F25Target temperature not reachedMiele
• 1E / IEClogged filter or overheating (depends on model)Samsung
• HC / HEHeater or overheating errorSamsung
• tE / tCTemperature sensor errorSamsung
• F3E2Temperature or soil sensor faultWhirlpool
• Sanitize light flashingLoad was not sanitizedWhirlpool

Last reviewed 2026-10-19.