ssd fail after water damage

So after an unfortunate accident with water my daughter's macbook air seems to have suffered a failed ssd. I've taken the computer apart, dried and checked for damage. But now, when booting, it can't find the SSD. I did a diagnostic test and it says "There may be an issue with a storage device". The laptop is no longer under warranty, so I guess that means the best option is to put a new ssd in it. But %#*@, they are expensive. I'm worried that if I purchase a new drive, it might turn out that its not the ssd but the logic board, and I would have wasted a heap of money.

Does anyone have any insight into the probability that the SSD is the only issue? Or a way to check that it is actually the ssd? Or a suggested course of action?

Thanks