Subaru 2002 Impreza Service Manual page 103

EVAPORATIVE EMISSION CONTROL SYSTEM
Emission Control
(Aux.
Emission Control Devices)
H: VENT VALVE
The vent valve is located on the fuel tank. During filling the fuel tank, fuel vapors are introduced
into the canister through the vent valve.
When the fuel vapor pressure becomes higher than the atmospheric pressure and overcomes the
spring force which is applied to the back side of the diaphragm, the port toward the canister is
opened. The vent valve also has a float which blocks the fuel vapor passage when the tank is filled
up. Increasing fuel level raises the float to close the port toward the canister.
B -
(1) Spring
(2) Diaphragm
(3) Plate cover
(4) Packing
(5) Float
(6) Float spring
H2H3224B
A: To filler pipe
B: To canister
EC-17