Canister Purge Control Valve: Description and Operation

EVAP Vacuum Switch:

The EVAP Purge Vacuum Switch is used by the VCM to monitor EVAP canister purge solenoid operation and purge system integrity. The EVAP Purge Vacuum Switch should be closed to ground with no vacuum present (0% EVAP Purge PWM). With EVAP Purge PWM at 25% or greater, the EVAP Purge Vacuum Switch should open.

An incorrect EVAP Purge system flow should set a DTC P0441. A continuous purge condition with no purge commanded by the VCM should set a DTC Pi 441. Refer to Evaporative Emission (EVAP) Control System for a complete description of the EVAP system.