Frigidaire error code i40: The incoming water temperature is below the minimum threshold required for effective cleaning. The dishwasher detects this at the start of a heated wash cycle.
The incoming water temperature is below the minimum threshold required for effective cleaning. The dishwasher detects this at the start of a heated wash cycle.
Disconnect power. Locate the thermistor (usually near the heater or on the wash tub). Check the connector for loose pins or corrosion. Reconnect firmly.
Tools needed: Screwdriver set
With power off, disconnect the thermistor connector. Measure its resistance with a multimeter. At room temperature (20°C / 68°F) most NTC thermistors read around 10,000–15,000 Ω. Refer to your model's service sheet for exact values. A reading of 0 Ω (short) or infinite Ω (open) means replace the sensor.
Tools needed: Multimeter
A shorted heater element can pull down the thermistor reading. Disconnect the heater terminals and retest the thermistor in isolation. If the thermistor reads correctly with the heater disconnected, test the heater separately.
Tools needed: Multimeter
Moisture in the sensor connector can mimic a shorted thermistor. Dry the connector with a hair dryer on low heat and reconnect. Run a cycle to see if the error clears.
Tools needed: Hair dryer
If the sensor tests out of specification, replace it with the OEM part for your model. Thermistors are typically inexpensive ($10–$30) and require only a screwdriver to replace.
Tools needed: Screwdriver set
Run the hot tap at the adjacent sink until water feels hot before starting the dishwasher. If inlet water is genuinely hot and i40 persists, test the inlet thermistor.