KN - Testing Notes

Fuel Pressure Regulator Control (FPRC) Solenoid:

NOTE: You should enter this Pinpoint Test only when you have been directed here from Diagnostic Routines.

REMEMBER: To prevent the replacement of good components, be aware that the following non-Electronic Engine Controls (EEC) areas may be at fault:

- Damaged fuel pressure regulator

- Damaged vacuum hoses

- Engine operating temperatures

- Base engine (valves, vacuum leaks, timing, etc.)

This Pinpoint Test is intended to diagnose only the following:

- Fuel Pressure Regulator Control (FPRC) solenoid

- Harness Circuits: FPRC, and VPWR

- Powertrain Control Module (PCM) (12A650)

DESCRIPTION
The Fuel Pressure Regulator Control (FPRC) solenoid controls the vacuum applied to the fuel pressure regulator. The FPRC solenoid contains a valve with two ports. One port is connected to the manifold vacuum. The second port is connected to the fuel pressure regulator. The FPRC solenoid also has an air filter cap (vent) on it. If the solenoid is energized, the solenoid valve closes the manifold vacuum path to the second port which leads to the fuel pressure regulator. This results in a higher fuel pressure during crank, idle, neutral and wide open throttle drive modes for a predetermined time and engine temperature. If the solenoid is not energized, then the solenoid valve opens the manifold vacuum path to the second port allowing the manifold vacuum signal to be applied as input to the fuel pressure regulator.