The purge solenoid is a pneumatic device that meters the air and fuel (purge) vapor flow to thepurge port. In a sense, the purge solenoid is comparable to a fuel injector, because the meteredpurge flow follows the same slope and offset characteristics. However, the purge solenoidnormally runs with a duty cycle at a fixed frequency because the opening response is significantly slower than a fuel injector. It would not practical to run the solenoid synchronouslywith engine events except perhaps at very low RPM. The normal frequencies for the purgesolenoid are between 8 and 20 Hz.

Checking output signals from PCSV every 10 sec. under detecting condition, if signals indicating open or short to ground in the circuit are detected for more than 5 sec., PCM sets P0444. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.