DeVille V8-4.9L VIN B (1995)
Canister Purge Solenoid: Description and Operation
Canister
OPERATION
The Evaporative Emissions (EVAP) solenoid receives 12 volts from the fuse panel. The Powertrain Control Module (PCM) energizes the EVAP
solenoid by grounding CKT 428. When the solenoid is energized, it allows the canister to purge. When a purge mode is commanded, stored fuel
vapor is drawn into the inner dip tube through a calibrated orifice at the base of the tube. Any liquid trapped in the liquid well is also drawn into
the inner dip tube through a smaller calibrated orifice. Fresh air is drawn into the canister at the top mounted vent.
Under cold engine, "OPEN LOOP," or idle conditions, the solenoid is de-energized by the PCM, which closes the purge solenoid and blocks
vacuum to the canister.
The canister will be enabled (PCM energizes the solenoid) when:
^
Coolant is above 80°C (176°F).
^
Closed loop has been achieved for at least 30 seconds.
^
The throttle switch is open.
^
Vehicle speed greater than 10 mph.
^
Engine speed above a threshold.
OR
^
Code P013, P017, P042, P043, P044, or P045 is present.
If the solenoid is closed, (not receiving power or has a stuck plunger), the canister will not purge to the intake manifold. This will prevent the
canister from purging fuel vapors and could result in a complaint of fuel odors coming from the engine compartment.
LOCATION
The solenoid is located in the LH side of engine compartment, attached to canister.
