Ford 6.4L Power Stroke, Manual

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ElEctrical componEnts
114
FRP (Fuel Rail Pressure)
• The FRP sensor is a (3) wire variable capacitance sensor.
• The ECM supplies a 5 volt reference signal (Vref)
which the FRP sensor uses to produce a linear
analog voltage that indicates pressure.
• The primary function of the FRP sensor is to provide a feedback
signal to the ECM indicating the pressure of the fuel in the fuel rail.
• The ECM monitors FRP as the engine is operating to modulate
the PCV. This is a closed loop function which means the ECM
continuously monitors and adjusts for ideal FRP determined
by conditions such as load, speed, and temperature.
• The ECM monitors the FRP signal to determine if the
performance of the fuel system is satisfactory.
• During engine operation, if the ECM recognizes that the FRP
signal is lower or higher than the value the PCV is trying to
achieve the ECM will set a Diagnostic Trouble Code (DTC) and
illuminate the amber malfunction indicator lamp on the dash.
• The FRP signal to the ECM is one of the signals used
to command the correct injection timing.
• This sensor is replaceable.