Fuel Pressure Sensor: Description and Operation

Fuel Pressure Sensor (Only Vehicles With Demand Controlled Fuel Pumps)







The fuel pressure sensor is combined and consisted of both the fuel pressure sensor and the fuel temperature sensor. The sensor detects the fuel pressure (the absolute pressure) and the temperature of the fuel in the fuel rail.

Fuel Pressure Sensor
The pressure sensor is a Piezo resistive type resistor, the resistance of which changes with the pressure. Depending on the pressure in the fuel rail, an analog signal of 0 - 5 V is transmitted. Low pressure results in low voltage, high pressure in high voltage.

The engine control module (ECM) then uses this signal to adjust the pressure in the fuel rail using the fuel pump control module. Also see Function.

The pressure sensor is supplied with 5 V and grounded in the engine control module (ECM). The pressure sensor transmits a signal indicating the fuel pressure to the engine control module (ECM) on a separate cable.

The engine control module (ECM) can diagnose the fuel pressure sensor. Its signals (pressure and temperature can be read using VADIS.

NOTE: The absolute pressure is displayed when using VADIS parameter read outs to read off the fuel pressure. If there is no pressure at the fuel rail, the atmospheric pressure will be displayed.

HINT: The relative pressure (absolute pressure minus atmospheric pressure) is displayed when reading off the fuel pressure via a manometer connected to the fuel rail.