HiCustomer here are the replacement directions, this is the easiest way to replace it without disassembling the top of the engine, hope this helps.
CERTAIN 2003 MODEL YEAR F-250/350/450/550 SUPER DUTY AND EXCURSION VEHICLES EQUIPPED WITH 6.0L DIESEL ENGINES - INJECTION CONTROL PRESSURE (ICP) SENSOR REPLACEMENT
ICP SENSOR REPLACEMENT
NOTE: The ICP sensor is located at the top of the engine and is accessible from below once the turbocharger heat shield is removed. Due to space limitations, a deep flare nut crowfoot wrench is recommended for sensor removal and installation. This procedure is consistent with the workshop manual revision due for release during the week of April 14, 2003.