Evaporative Emissions System: Notes

The evaporation control system prevents the emission of fuel tank vapors into the atmosphere. When fuel evaporates in the fuel tank, the vapors pass through vent hoses or tubes to a charcoal filled evaporative canister. The canister temporarily holds the vapors. See EVAP CANISTER  . The Powertrain Control Module (PCM) allows intake manifold vacuum to draw vapors into the combustion chambers during certain operating conditions. All engines use a proportional purge solenoid system. The PCM controls vapor flow by operating the purge solenoid. See EVAP CANISTER PURGE SOLENOID  . A Natural Vacuum Leak Detection (NVLD) assembly is used as part of the evaporative system. See NATURAL VACUUM LEAK DETECTION ASSEMBLY  . Vehicle is also equipped with On-Board Refueling Vapor Recovery (ORVR). See ON-BOARD REFUELING VAPOR RECOVERY  . The evaporative system uses specially manufactured lines/hoses. If replacement becomes necessary, only use fuel resistant, low permeation hose.