This post is about a 2013 Hyundai Santa Fe. But I figure someone here knows the answer. My father-in-law couldn’t fuel his Hyundai; the pump would continually click off. I removed the EVAP canister and charcoal poured out of the lines. What happened is that the little foam screen that keeps the charcoal from escaping deteriorated. So I was able to pour ALL of the charcoal out of the canister, then I reattached the hoses and put it all back together. The car runs fine and we can add fuel without any difficulty. A replacement canister is about $550. Alternately, I can cut the canister open, put a new screen in to keep the charcoal pellets in place, and either put the charcoal back in or fill with fresh charcoal (if I can find any), then glue the canister back together. OR, I can leave it as-is. THE QUESTION: (Yes, finally, I’m getting to the question!) Can I cause any damage or harm by just operating the vehicle with no charcoal in the canister? I haven’t smelled any fuel (I tried). The car runs fine. So, can this cause any sort of damage?
I did almost exactly this repair on a different Hyundai. Instead of opening the canister and installing a new screen, I made my own screen a few inches down the hose, so the charcoal couldn't get very far. Worked perfectly for at least 6 months- unknown beyond that due to sale. You can use grocery store cooking charcoal- the trick is to get the lump style and break it into smaller pellets.
I had always believed the stuff in the canisters is activated charcoal. There seem to be various processes involving heat or chemicals that 'pop' charcoal like popcorn into a form with a lot more surface area for the same mass. The linked Wikipedia article suggests about a thousand times the surface area of plain charcoal. (!) But the top "shopping" links in my Google search for activated charcoal are showing, like, 50 pound bags for $9.20. Doesn't seem hard to get the stuff.
Or just reuse the old. I know though: good opportunity to refresh it, if you can get the right stuff.