Canister Purge Solenoid: Description and Operation

The canister purge is controlled by a solenoid that allows vacuum to purge the canister when de-energized. The ECM supplies a ground to energize the solenoid (purge "OFF"). If the diagnostic terminal is ungrounded with the engine stopped or the following conditions listed below are met with the engine running, the purge solenoid is de-energized (purge "ON").

^ Engine run time after start more than 1 minute.
^ Coolant temperature above 75°C.
^ Vehicle speed above 15 m.p.h..
^ Throttle off idle.