My 2004 1.8 Vibe base with 160,000 miles check engine light came on. It showed a PO442 Small Evap Leak code. I started with all the cheap fixes first like re-tightening the gas cap, then replacing the gas cap which didn't work to clear the codes. Then I heard the 2004 corolla/Matrix had a service bulletin with an improved fuel filler tube was made to correct PO442 code condition. That didn't work either. After clearing the code, it came back on a few days later. After going to get the EVAP system smoked, they said it might be the thick rigid plastic hose that goes from the Charcoal Canister to the fuel tank cut off valve. That was a waste of money cause the light came back on. Next, I tried changing out the purge and vent valve solenoids cause they weren't that expensive and easy to change. But no luck. The check engine light still came on. I was just about to give up and put electrical tape over the light in frustration. My last attempt was to just take a chance and replace the Charcoal Canister. I saw one on Rockauto.com for $200 for an AC Delco OEM Canister which was basically a Toyota OEM canister repackaged under AC DELCO name but $100.00 cheaper than what Toyota wanted for one. So I gave it a shot as a last ditch attempt to fix it before I just gave up. And what do you know, it fixed the problem. I cleared the codes after replacing the canister and 3 weeks later and a couple of tank fulls of gas later, the engine light hasn't come back on and when I checked it again with the OBD II Scanner, it shows no pending codes. What a relief! I'm back in love with my Vibe again.
With all the parts I changed out I basically have a new Evap System. So I should be OK for awhile when it comes to the Evap System. lol
Hope this helps someone if they encounter the same issue to hopefully save them money and headaches that I had to deal with.