Silverado check engine light

I got in to my truck this morning and the check engine light came back on… again. The infamous code is P0446. I have already looked into a TSB that GM issued and replaced the vent valve solenoid and I also replaced the tube. I think the only thing left to check is the carbon canister. Is there a way of testing a carbon canister? I read some where that the canister may be saturated with fuel. I just filled up on Sunday drove it everyday and the light came on Wed. Any thoughts would be appreciated.

You didn’t give the year of the truck and where you live, which may have something to do with the problem. My 2001 Silverado here in upstate NY showed the code for a problem in the evaporative system. It turned out that the top part of the fuel filler tube had rusted enough to allow an opening int he tube, so it was like having a loose gas cap. If the P0446 code is that same as what was on my truck, and if you are in an area where rust is a problem, this one area for you to check.