CEL on, code 455 2007 Mal Maxx 3.5L

The code 455 is set. Also the radio says "check gas cap". I took off the locking gas cap and put on what I think was the OEM gas cap. Actually I have 3 or 4 gas caps. They are from my 2003 Impala , the Maxx and a 98 Malibu... they all fit..so probably doesn't matter. I have tried all the other caps but one...they all say "check the gas cap". I don't think it is the cap.
any ideas?

I'm not a techie, so I don't have a clue what Code 455 is, but I've had my '04 Maxx for almost 5 years.....

The "Check Gas Cap" on the DIC was a common problem with the '04s and '05s - my Maxx needed a new fuel tank shortly after purchase. No problems since. Maybe the '06s and '07s are developing the same problem?

The CEL can mean a slew of things. Mine was on about 6 months ago and it turns out I needed a new thermostat.

These cars are very "moody" and, like the legions of folks in here trying to resolve issues with the '97-'03s on their own, it will probably prove to be mostly true that a good Chevy dealer is our best friend. Until the economy improves and I can trade it in for a new vehicle.

The code is actually P0455 and could be anywhere in the EVAP Emissions Control system.

http://www.obd-codes.com/p0455 go here and look to see what to check after checking the gas cap. You did do right it says that is the first thing to check.