Diagnostic Aids
The Injection Control Pressure (ICP) sensor is a variable capacitance sensor that, when supplied with a 5-volt reference signal from the Powertrain Control Module (PCM), produces a linear analog voltage signal that indicates pressure. The ICP sensor's primary function is to provide a feedback signal to indicate rail pressure so that the PCM can command the correct injector timing and pulse width and the correct injection control pressure for proper fuel delivery at all speed and load conditions.
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.
If the PCM detects an out of range high or low ICP sensor, the Malfunction Indicator Lamp (MIL) is illuminated and the PCM will function from an estimated injection control pressure (open loop control of injection control pressure).