fault 48 is "less than around 3 volts at T2"
so either something is pulling the voltage down to negative, or it is not getting battery volts to start with
have you swapped out the main traction power fuse, these often test good when are actually cracked internally
have you actually measured these voltages when fork faults
check the white/blue and blue wires in PC Z on the scr card for spread terminals
when you changed the 1 rec did you change the little white plastic insulator sheet underneath it
here is the ev100 general manual if you dont have it
https://www.shop.fsip.biz/Image/GetDocument/en/80