Fuel Rail Pressure And Temperature Sensor
The FRPT sensor is located at the top of the fuel rail. The FRPT sensor is screwed into a threaded port and sealed with a mating taper in the fuel rail. The sensor is connected directly to the PCM .
The FRPT sensor is a metal thin film technology type sensor. The sensor is connected with 4 wires to the PCM . The PCM supplies a 5V reference voltage to the sensor. The pressure measurement is based on the expansion of a thin steel diaphragm which is sensed by the PCM on a return signal wire which is proportional to the fuel pressure in the fuel rail.
The PCM compares the sensor signal voltage to stored memory values, to calculate the actual fuel pressure present in the fuel rail. The PCM then uses the fuel rail pressure information to control the operating position of the fuel metering valve.
The FRPT sensor contains a Negative Temperature Coefficient (NTC) sensor which allows the PCM to determine the fuel temperature.