Hi @fe2najt8jfcnod
The number you posted i.e. MEZ41911003 is a serial number for the washer and not the model number.
According to LG the serial number ''may'' be applicable to any of the following models.
If your model is one of the following, to activate/deactivate the Child Lock (CL) function, turn on the machine by pressing the Power button and then ''press and hold'' the buttons indicated below for the amount of time shown
WT1501CW Soil (*child lock) button for 3 seconds
WT1901CK Soil level (*control lock) button for 3 seconds
WT7200CW Signal (control lock) button for 3 seconds
WT5720CW Signal Off-Low-High (child lock) button for 3 seconds
WT5480CW Water Plus (*child lock) button for 5 seconds
''Note'' The child lock/control lock designation is printed on the machine under the relevant button