Hi started new thread for my CEL. First got " Check Gas Cap" Message. I cleaned the filler tube surface and replaced gas cap with new one. A couple days later got message again with CEL. Code PO496. Replaced Evap Solenoid under hood and cleared codes with scan tool. Went 4 days and got gas cap message again with CEL. Code now is PO455. Which is a EVAP leak. Any help would be appreciated Thanks

'09 SS, Auto, 100K miles

 

EVAP line leak? They are prone to rust, same as the fuel line...

 

As shown in here

https://www.obd-codes.com/p0455

inspect the EVAP tube mine leaked fumes at a rusted section of the vapour tube just inside the insulation by the drivers side ( that would be the left side) rear tire. Small pin holes developed in the line.

 

thanks. How did you find the hole?

 

The line will rot at the back . Take off any foam you see around the steel line, clean and inspect.
You could go to the front of the line and blow low pressure air in it and spray the line with soapy water. Bubbles? There's your leak

 

Could be the end of the fill tube has crap on it so the cap can't seal (after you do the 2 clicks close).

 

I explain in this

https://www.chevyhhr.net/forums/prob...l-odour-59973/

 

Checked vapor line in back of car where it goes to canister. No rust. Line looks pretty clean. Looks like the fuel line was replaced at some point by P.O . Now have P0455 CEL

 

Check the canister area under the rear of the SS, have changed the fuel cap ?

https://www.obd-codes.com/p0455

 

EVAP vent valve, next to gas tank. Or the O-ring seal.

Not unusual for it to take a few days after you clear codes, The EVAP tests are the last to run and need several circumstances.