EVAP Canister
WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
The EVAP canister, filled with charcoal pellets, stores the fuel vapors from the fuel tank. Vacuum is pulled from the fuel tank through the vapor pipe. Fresh air is mixed with the vapors and pulled to the intake manifold from the canister through the purge line. The engine vacuum purges the EVAP canister during normal driving. See Fig 2 .