@dc42 I have went through the entire schematic multiple times and the only reference I can find to the Z_PROBE_IN is the header pinout. The only inputs I see are for Z_PROBE_MCU and Z_PROBE_MOD. Thanks for the reply

Can anyone help me out figuring out what the z_probe_in pin name is? I know 51 is the logical pin number, but I am looking for the specific signal name like PA1.

Thanks
Brian