Recently picked up a 2019 F350. It was a fleet vehicle and had a lot of caked-on mud in every nook and cranny. From day one was having refueling issues where the pump shuts off multiple times when refueling. Had a shop replace the purge and vent solenoids, hoping this would address the issue. Unfortunately, replacing those solenoids did not fix the refueling issue, and started getting P0496 codes after driving 5-10 miles after the work was done. The shop looked into it again and replaced the solenoids once more and the charcoal canister (they found a lot of dirt in there). After that work, the shop claimed the truck refueled without issue, but I was not there to verify.



I took the truck out this last weekend for a short trip and the check engine light came on again (drove about 90 miles) and it's P0496 again. Shortly after the check engine light came on, I had to refuel the truck and it's still having the same refueling issues. I'm over it with the shop and gonna try and tackle things myself, but could use some help in figuring out where the issue is. If solenoids were replaced and the canister was replaced, what else might be causing the error code? Should I replace the pressure sensor, purge flow sensor, do another smoke test, or all of the above?

 

What the code suggests is, purging is taking place when it should not be.
The purge solenoid could be getting power when it should not be or is sticking open.
This will require actually checking the valve physically for possibly sticking open or getting power when it should not be.