Canister Purge Solenoid: Description and Operation

ECM controls vacuum to the purge valve through the purge solenoid.
- When the engine is cold (open loop), the solenoid valve is energized, blocking vacuum to the purge valve.
- When the engine is warm (closed loop) and operating above a preset engine or vehicle speed the solenoid valve is de-energized, allowing vacuum to be applied to the purge valve.