Purge Valve

WARNING: This page is about a different car, the 2018 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

The purge valve is located on the left side of the engine, forward of the intake manifold. The valve is attached to a bracket which is secured to the camshaft carrier.

The vapor purge hose from the charcoal canister connects into the upper connection on the valve. The middle connection provides for the connection to the inlet manifold. The bottom part of the valve is a venturi used to create a vacuum in the valve to allow purging of fuel vapor when used on boosted application. An electrical connector on the top of the valve connects with the vehicle engine wiring harness.

The purge valve is operated between 10 Hz and 30 Hz during idle and on 10Hz outside of idle by a Pulse Width Modulation (PWM) control ground from the Powertrain Control Module (PCM). The purge valve receives a fused power supply from the Engine Junction Box (EJB). At this high frequency, pulses of fuel vapor flow into the intake of the intake manifold in an almost continuous flow. The valve operates at a duty cycle of between 7 % and 100 %.

Atmospheric pressure in the evaporative emissions canister is higher than the pressure at the intake manifold inlet or venturi under all throttle settings and engine running conditions. This pressure differential allows vapor to be drawn from the evaporative emissions canister. The vapor is drawn through the open purge valve and into the intake manifold air intake or air intake into the throttle.