Fuel Pressure Control Valve

The fuel Pressure Control Valve (PCV) is mounted in a threaded bore on the rear of the fuel rail. The fuel PCV is connected to the Powertrain Control Module (PCM) via the engine harness. The fuel PCV is a solenoid-operated valve controlled by a Pulse Width Modulation (PWM) signal. The PCM operates the fuel PCV to adjust the fuel pressure within the fuel rail. Relieved fuel is directed through the fuel rail leak-off pipe to the fuel filter return circuit. The returned fuel is used to warm the filter.

The fuel PCV is normally open when the solenoid is not energized by the PCM.

The fuel PCV is also used by the PCM to provide direct control of the fuel system, in the following situations:

• During sudden transient phases in engine speed (suddenly lifting off the accelerator pedal, for example) where the fuel metering valve action is not sufficient to affect the supply of fuel to the fuel rail.
• To control fuel pressure if the fuel metering valve fails.
• During the fuel heating period, when supply fuel temperature is less than 15°C (59°F), the fuel metering valve is fully opened by the PCM. The High Pressure (HP) fuel pump compresses a maximum quantity of fuel to raise the fuel temperature. The fuel PCV is then modulated by the PCM to provide leak-off fuel from the fuel rail to the fuel filter return circuit. The fuel is then recirculated through the fuel filter and back to the HP fuel pump.
• During engine shutdown to progressively collapse the fuel rail pressure.