LDP problem with liberty. HELP

A buddy of mine is having a problem with his liberty . The problem started two weeks ago when the check engine light came on. I had him do the test for it and the codes came up PO455 and that the LDP failed.
Can this be caused by a bad gas cap or one that was left off? Or does it have to do with the charcoal canister or the EVAP canister?
Please give me any answers

A buddy of mine is having a problem with his liberty . The problem started two weeks ago when the check engine light came on. I had him do the test for it and the codes came up PO455 and that the LDP failed.
Can this be caused by a bad gas cap or one that was left off? Or does it have to do with the charcoal canister or the EVAP canister?
Please give me any answers

My wife's Liberty had the same problem. Try the gas cap (it's a $14 fix if it works). I believe you will need to cycle the computer - just disconnect the battery for a few minutes - to get the light to shut off. It takes any where from 20 to 50 miles for the "check engine" light to cycle again IF it's going to come on again.

My wife had a crack in the line leading from the gas cap to the tank, it was split on the top, so it was a pain to actually find.

we see cracked hoses all the time at the dealer, gas cap does work sometimes others do need leak detection pump the dealer can do whats called a smoke test and find the leak but labor time can run 1/2 hr to 1 1/2
hrs