Have a small evap leak pO456 code on an 04 4runner v6. Already replaced the gas cap. Not sure what any of the other causes could be. Had two o2 codes as well. Replaced one sensor. Was told 02 codes and evap codes are not connected.
No they aren’t related the evap codes is specific to the fuel tank vapor system. Unfortunately unless you have to ability to close and pressurize the system it can be tricky to diagnose. You could start with a visual inspection for any cracked or rotted through lines to the fuel tank and the filler neck to eliminate anything more obvious
Ok thank you. I heard a smoke test would help?
The smoke test will definitely help you isolate the evap concern. In most cases the gas cap seal can cause this as well as vent control valve depending on the code you have