Page 108 - Foton Workshop Manual - Auman EST-M

DI - 54 Diagnosis - Diagnosis-fault diagnosis of electronic and electrical parts

Fuel pressure sensor failure
451-circuit of fuel injector measuring rail pressure sensor 1-higher voltage above normal value or short
to high-voltage power source
452- The voltage of injector metering oil rail pressure 1 sensor is lower than the normal value or short
to the low voltage power supply

Overview
1. The fuel pressure sensor shall be installed on the common rail tube, and the fuel pressure sensor provides an
instant fuel pressure of common rail tube to ECM to realize the common rail pressure closed loop control of
ECM. When the common rail exceeds the maximum pressure which can be undertaken by the common rail
pipe, the rail pressure limit valve will open automatically to reduce the common rail pressure to ensure the
safety.
2. The fuel pressure sensor is a varistor-type sensor. The fuel flows to the fuel pressure sensor through a small
hole of its common rail, and the pressurized fuel reaches the sensor diaphragm through a blind hole. A sensor
part which converts the pressure signal to electric signal is installed on the diaphragm. The signal produced by
the sensor is transferred to the input signal processing unit and sent to the testing loop of ECU.
Circuit diagram

Engine ECM

Pressure
Sensor + Sensor +
signal

Black Brown Red

Rail pressure sensor

DI-054