1998 oldsmobile intrigue abs help

I pulled the abs codes in my 98 intrigue today and one of them is a “Master cylinder pressure senor” code but looking at a diagram on google it does not seem to point out anything but the master cylinder/abs unit and i dont know the actual name of the part. Can anybody who has knowledge about abs repair or oldsmobile parts point me in the correct direction? (number 26 is pointing to what the sensors bolt onto)