DTC P0442-00: Evaporative Emission System-Leak Detected (Small Leak): General Description

The purge solenoid is a pneumatic device that meters the air and fuel (purge) vapor flow to the purge port. In a sense, the purge solenoid is comparable to a fuel injector, because the metered purge flow follows the same slope and offset characteristics. However, the purge solenoid normally 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 synchronously with engine events except perhaps at very low rpm. The normal frequencies for the purge solenoid are between 8 and 20 Hz.