Circuit/System Description

The fuel rail pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the fuel rail pressure sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

The engine control module performs a series of diagnostic test under set calibrated conditions to determine if the fuel rail pressure sensor is performing as expected. These tests are performed at idle, during high fuel pressure demand conditions, and low fuel pressure demand conditions. The ECM also tests for a stuck or slow reacting fuel rail pressure sensor.