My check engine light is on. I took it to Auto Zone and got the P0449 code Evaporative Emission System Vent Control Circuit Intermittent. I replaced the gas cap and the solenoid and the check engine light still comes on after being reset. The P0449 code still comes up on Auto Zone's code readers after replacing both of them. I also get the P0521 code. I have not started to troubleshoot that one yet. Any suggestions on the P0449 code.

 

If the replacing the gas cap and canister vent valve solenoid under the spare tire didn't fix the problem, you have a leak elsewhere. Visually inspecting the lines from the canister to the tank back to the engine compartment may help pinpoint it. Sometimes, the Vapor Canister Purge Valve on the driver side of the engine under the cover can pop free of the tube.

If you don't find any issues, you'll need to smoke the system and looks for smoke leaking out.