hi new here first time to post got this code when i scanned the truck checked the hoses and elbows all around the canister didnt hear any leaks or see any wanting to know if there is a better way to check for the leaks other than just listening and also can the canister itself just quit working can this also trip a po171 code thanks

 

P0455 Gross Evap Leak most commonly occurs because the gas cap is not installed correctly.

The P0171 is possibly related if there is a major leak in the purge line to the CV solenoid.

A fault in that section could explain both codes.

Steve

 

checked the gas cap it seems to be ok how do i check the purge valve to see if it is working

 

i checked the gas cap and around the filler neck like where the fuel pump hits it is chiped would thatcause it to trip this code

 

That could cause it if the outer lip of the filler is chipped where the cap seals.
A more common problem for a P0455 is a bad Canister Vent Solenoid or the wiring to it.
If you do a search in here I think you'll find a few posts about it.