I got a CEL two weeks ago, and after going to Autozone for a ODB2 scan, they came up with these two codes:

P0455 - EVAP Control System Gross Leak
P1448 - EVAP Canister Vent Control Valve Open

After doing some searching, I found out that several people have had this issue before, and that this is a non-critical "ghost" error code(s). Here is what I did to fix the problem:

1. Disconnect the battery for at least 1 hour.
2. Unscrew, and re-tighten your gas cap.
3. Drive around for several days. It took me about 5-6 separate trips, with turning the car on and off for the light to go away by itself.
4. Your sunroof will not operate properly because the "home" position for the sunroof is lost. I left it alone for about 15 minutes of driving, and it re-learned and was fine by itself.
5. Autozone tech told me to take the key out of ignition when filling up. He seemed to think this was the problem for the error codes. I don't know if it's true, but I do this now.

Mods, if you could link this up in the FAQ page (http://forums.maxima.org/showpost.ph...&postcount=100), it may help some people in the future. Thanks.

 

You can manually reset the sunroof right after you reconnect your battery... instructions are on page 2-29 of your owner's manual...