LG Washer Error Code 1tC1

The 1tC1 code indicates a temperature sensor error in the upper washer's washing heater circuit. The control board is not receiving a valid signal from the thermistor that monitors the heating element during the wash cycle. The washer will disable the heating function and display this code to prevent potential overheating. The fault typically points to a connection problem, a failed sensor, or a damaged wiring harness.

The washer's heating function will be disabled while this fault is active, so the machine will not heat water properly during a wash cycle. Running the washer in this state is generally not dangerous, but wash results will be affected, particularly for cycles that require heated water. It is best to resolve the fault before continuing regular use to avoid potential progression of the underlying issue.

Unplugging the washer for a few minutes and restarting it may temporarily clear the 1tC1 code, but the error will return if the underlying fault has not been corrected. A reset is useful for confirming whether the fault is intermittent, such as a loose connector that reseats itself, versus a hard failure like a burned-out sensor. Persistent reappearance of the code after a reset is a strong indicator that a component needs to be tested or replaced.

Checking and reseating the washing heater temperature sensor connector is a reasonable DIY first step and requires no special tools. If the connector is secure and the error persists, testing the thermistor resistance with a multimeter is the next step, which is within reach for experienced DIYers. Replacing the sensor or wiring harness is more involved and may require partial disassembly of the washer. If the control board is suspected, professional diagnosis is recommended.

If the fix is simply reseating a loose connector, there is no parts cost involved. Replacing a washing heater temperature sensor typically costs between $15 and $60 for the part, depending on the model. If a wiring harness or control board replacement is needed, repair costs can range from $100 to $350 or more including labor. Getting a professional diagnostic assessment first can help avoid unnecessary parts replacement.