Volkswagen Golf, GTI, Jetta 1999-2004, Jetta Wagon 2001-2004 - 1.8 Liter 4-Cyl. 5V Turbo Engine Mechanical, Engine Code(s): AWD, AWW, AWP
20-49
The pressure retention valve prevents fuel vapors from
being drawn from the tank when the solenoid valve is
open and intake manifold vacuum is present. It therefore
ensures that the evacuation of the EVAP canister has
priority.
No voltage (e.g. wiring open circuit) the solenoid valve is
closed and the EVAP canister will not be purged.
The vacuum line from the throttle valve control part to
the EVAP canister has an additional by-pass which is
connected with the cylinder block breather valve. The
non-return valve integrated in the cylinder block
breather valve prevents the intake air gassing into the
cylinder block during some partial load ranges. This
improves the overall cylinder block breathing. The by-
pass guarantees the cylinder block breathing.
Functional description of leak diagnosis
The evaporative emissions system (including fuel tank)
is equipped with a leak diagnosis, the leak diagnosis will
detect whether the system is leaking.
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