Injection Control Pressure (ICP) Sensor
The 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 primary function of the ICP sensor is to provide a feedback signal to indicate the rail pressure so that the PCM can command the correct injector timing, pulse width, and the correct injection control pressure for proper fuel delivery at all speed and load conditions. The ICP sensor along with the injection pressure regulator (IPR) form a closed loop fuel pressure control system.
If the PCM detects an inoperative ICP sensor, the PCM controls the injection control pressure from the estimated injection control pressure.
The ICP sensor bias varies between sensors. The amount of voltage the sensor deviates from a calculated reference value (sensor bias) may cause an injection control pressure calculation error.