He took the canister off the truck.
My canister doesn't have any checks in it. It is a sealed(as in crimped) container. Just for housing the carbon used to absorb gas vapors.

Even if one got saturated it should be able to be purged with low pressure air to dry it out. The 40psi would be to blow any junk like dirt off of the surface area of the carbon.

 

Yep, my FSM lists ~40 psi compressed air to blow the cannister filter clean as well. Did that last spring and blew out all sorts of dust and dirt. Probably the original '85 cannister, nearly 270K miles on it, still seems to work fine. On the earlier engine, the Evap control is all passive and there is no monitoring of it's operation by the ECU, unlike on the more modern engines.

 

If there are no check valves and the manual says 40 psi, then go for it.
Sounds quite different than the newer versions.

 

Your's only has two years on mine, "MTL", so I would'nt think that they would be all that different.
As an aside...should I damage the charcol cleaning the canister in the fashion I've described, I could always take it a step further by raising or removing the rubber cover-cap on the the top of the canister, exposing an eared "O" ring nut that I could tap off with a hammer & screwdriver (or maybe just use a large pair of channel lock pliers & little pressure).
Then, removing it & the then unaffixed "purge" & "tank" pipe assembly unit with accompanying "basket" as a whole, I could shake out whatever's left of the old charcol & replace it with some charcol brickets (the old school, plain, non-quick start/light type) that I've bashed a couple of times into little chunks, therby completely refreshing the charcol filtration element of the canister.



Damn ! I only just now realized that this thread was started back in May !!
Oh well, I hope that the tips helped those from then & those from now in need (kinda like "Back to the Future", huh ?!?)