According to LG’s website the TCL error code on an LG washing machine means that a sensor detects dirt or mildew.
The tcL code on the display indicates that it is time to run the TUB CLEAN cycle. The unit will let the customer know when it is time to run the cycle to help prevent buildup and odors in the machine.
It also says that it may help to add a mix of 1/4 cup of bleach and 1 quart of water before running the cycle.