2003 1500 Hemi 5.7 showing P440 error after doing the following:

1. New gas cap
2. Checked Evap & solenoid for broken hoses (none)
3. Cleared EVAP (Wasn't clogged)
4. Check for loose vac hoses (none)

I cleared the code by disconnecting negative battery, came on, went away then came back on again. However, it has been less than 400 miles since restting the codes.

 

Check the hoses going to the filler neck for dryrot and cracking.

 

I will check this out !

AutoZone employee says I need a new Vapor Canister Purge Solenoid. I checked this but didn't notice any cracks or clogging. Any truth to that?

 

any of the above could cause the problem but aside from the gas cap, most common is a cracked hose or broken clamp at the end of the hose, often right at the canister.

I have an evap system map in the FAQ section that will assist you in tracing the system hoses...

 

Found it. The hose above #10 and the hose above that one don't appear to have any visible cracks. Should I replace them anyway?

 

Honestly, Dodge uses cheap hose and even cheaper clamps (worst hose clamps I've ever seen). If I find myself working in an area where there are iffy hoses (or even properly working clamps) I replace. Hose is about a buck a foot at the auto parts store and good quality clamps (the kind with the screw you can turn with a screwdriver or a socket) are all of about 50 cents a piece...

I have very few factory clamps left in both my Grand Cherokee and my truck...

 

Yeah, they always cheap out with those springy tension clamps. When I replace them I also swap out with worm gear style clamps as they just secure better IMO.