It's not the tank breather line. The OBDII fault code was PO444 which indicates an open circuit on EVAP purge valve (fuel tank breather valve). I spoke with one of the service techs at the local dealer. He says it's most likely the solenoid on the EVAP purge valve went bad.
If I'm looking to replace the EVAP purge purge valve, what's the easiest way to get to the purge valve? Is it by removing the air filter housing?