Chosen Solution
Water spilled onto my late 2013 MacBook Pro, I was able to get the SSD out and copy all my data. The logic board was replaced today, but I see the flashing folder with “?” after starting up. I did not replace the I/O board, even though i see some sign of liquid. Chime was heard and Caps lock button does light up. I can see the SSD through Command Option R. However, when i exit, it asks me to choose startup disk and the list is empty. My SSD should be fine, what else could be the problem?
I would start off replacing the I/O board and its cable.
I bet that solution below will fix the problem: Hard Drive/OS not recognized after logic board replacement
