Error code · Dishwasher

Frigidaire Dishwasher Showing Th: A Thermistor Failure

Medium · inspection needed

Code: Th
Appliance: Dishwasher
Brand: Frigidaire
Warranty: 30-day workmanship

What Th means

Th appears on Frigidaire Professional direct-feed dishwashers, such as PLD4555RFC0 and PLD4375RFC0, when the control checks the thermistor, the temperature sensor in the water circuit, and finds a failure there. The control uses that sensor to judge wash and rinse water temperature. When the reading is missing or wrong, you may see Th on the display and the cycle may stop or behave oddly. This is an older dishwasher still found in many homes, and we repair it.

Common causes of Th

The thermistor and its plug connection
The wiring that links the sensor to the control
The input circuit on the control that reads the sensor

✓ One safe check you can try

1. Cancel the cycle and let the dishwasher sit for a few minutes. 2. Check that the water supply valve under the sink is fully open. 3. Run a short cycle and see whether Th returns. 4. If it does, leave the dishwasher unused and call us to schedule service.

! Why to stop there

A single Th that does not come back may only be a one-time reading problem and tells us nothing about the sensor.
We test the thermistor and its wiring before the control, so a loose plug is found before anyone talks about a board.
If the repair is not worth the cost on a dishwasher this old, we say so plainly.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Dishwasher codes

rAFrigidaire Professional Dishwasher Code rA: Switch in the Rinse Aid Dispenser RE / RFFrigidaire Dishwasher Codes RE and RF: Rinse Aid Switch Readout SdFrigidaire Dishwasher Code Sd: Detergent Dispenser Activated tuFrigidaire Dishwasher Code Tu: Turbidity Sensor Trouble UF (uF)Frigidaire Dishwasher Code uF: Vent Fan Not Running ULFrigidaire Dishwasher Stuck in UL Test Mode UO (uo / Uo)Why a Frigidaire Dishwasher Shows Uo and Will Not Start PFFrigidaire Dishwasher Code PF: Power Was Lost

ThTh questions

What does the thermistor do in my dishwasher?

It measures the water temperature so the control knows how hot the wash and rinse water is. If the control cannot read it, it may stop the cycle rather than guess. A thermistor is a simple part, and the reading problem is often in its connection.

Will the dishwasher still run with Th showing?

It may stop or run oddly. The control depends on the temperature reading, so we do not recommend running it repeatedly with Th on the display. That is why we test the plug and wiring before anything is replaced.

Is it worth repairing an older Professional dishwasher?

Often yes, if the sensor or its wiring is the cause. We give you a written price first and say honestly when a repair does not make sense. Where the cost is more than the dishwasher justifies, we will say so.

Book a visit

Still seeing Th?

A technician diagnoses it on site and gives you the price in writing before any work starts.

(713) 844-8518