My cadilac 2002 smell gas so bad every time I fill up my tank or when I turn the AC on any sugestions

Sounds like you have a fuel leak somewhere you can add a leak dye to your gas tank then use a dye light to trace the leak to its source.The first thing i would do is look for a leak visually if nothing found that way then add the dye.

I cheked and dont see any leak any specific place to start like a mecanic change the canister.and problem still

Show 4 codes po410 po440 p0741 and p1571

The P0440 is the only code i see that could be related to the smell.Check all you evap lines for cracks breaks or being disconnected.