Our 2010 2.4 4x2 patriot threw the p455 and 456 codes this week (gross and small evap system leaks). Resetting these caused them to return immediately. Gas cap is recently new, last time on the original cap we got a “gas cap” code on display, and changing the cap fixed the problem. Now we are just getting the codes. Started with the purge solenoid under the hood, replaced with new, no issues, codes still there. Friendly garage tested system with smoke, found no leaks, good n tight. Still codes. Now I’m thinking the canister and vent valve under the rear wheel. That is next. Does anyone know what exactly will throw these codes? Some kind of pressure test or ?. I believe there is a 2 piece contraption on that canister, a vent valve and the canister itself, have visual on canister, doesn’t look bad. Any help would be appreciated.