Whirlpool Microwave Error Code F3.T1

F3.T1 indicates a thermistor failure on the user interface board (UIB). The relay control board monitors a temperature-sensing thermistor connected to the UIB via the P2-to-P64 wiring harness, and when it cannot receive a valid reading from that sensor, it triggers this fault code. The microwave will typically disable normal operation until the fault is resolved.

No, the microwave should not be used while displaying F3.T1. The fault indicates that the temperature sensor on the user interface board is not functioning correctly, and the appliance will typically disable heating functions as a safety measure. Attempting to bypass or ignore this fault could result in uncontrolled operation or further damage to the control boards.

Repair costs vary depending on the root cause. If the fix is simply reseating a loose connector, the cost is minimal. Replacing a wiring harness or thermistor component typically falls in the range of $20 to $80 for parts. If the full user interface board requires replacement, parts costs can range from $60 to $200 or more, with additional labor charges if a technician performs the repair.

In some cases, yes. The first diagnostic step is to unplug the microwave, then inspect and firmly reseat the wiring harness connectors at P2 on the UIB and P64 on the relay control board. If the connectors were loose, reconnecting them and restoring power may clear the error. However, if the thermistor, wiring, or a board has failed, replacement parts will be needed.

Unplugging the microwave for several minutes and restoring power may temporarily clear the display, but if the underlying cause is not corrected, the F3.T1 code will return. A reset alone is not a repair. The thermistor circuit, wiring harness, and connectors need to be inspected and tested to resolve the fault permanently.