Injection Control Pressure Sensor
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2004 Ford RV Cutaway, 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, and 2004 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.
The injection control pressure (ICP) sensor is a variable capacitor sensor that is supplied a 5-volt reference signal by the PCM and returns a linear analog voltage signal that indicates pressure. The sensor measures the oil pressure in the high pressure pump cover (F-SuperDuty/Excursion - Early Build) or oil rail (E-Series or F-SuperDuty/Excursion - Late Build) and the PCM uses this information to determine injection control pressure. The ICP sensor along with the injection control pressure regulator form a closed loop fuel pressure control system.
If the PCM detects an inoperative ICP sensor, the PCM will control injection control pressure from a PCM-estimated injection control pressure.