LG front load washer, model number wm2101hw, is overfilling.

I'm trying to identify the problem and fix it myself. to my knowledge, there is no "error code" displayed on the instrument panel when it overfills.

I've watched a couple of online video's and it sounds like the most common problems are the water inlet valve, the pressure switch or the pressure tube that comes off of the pressure switch.

is there any way to quickly identify which of these it most likely is? also is there a way to figure out what the part number is so that I can order it?

Thanks