The function diagram for the EFP sensor includes the following:
• EFP sensor
• Electronic Control Module (ECM)
• ENGINE lamp (amber)
• FUEL FILTER lamp (amber)
The EFP sensor is a variable capacitance sensor installed in the rear of the fuel filter assembly (crankcase side). The ECM supplies a 5 V reference signal which the EFP sensor uses to produce a linear analog voltage that indicates pressure. The ECM uses the EFP sensor signal to monitor engine fuel pressure and give an indication when the fuel filter needs to be changed.