I have replaced vent valve, purge valve, egr valve, pcv valve and 0455 still shows up. I have checked line and hoses and they seems to be fine. Can you suggest what I can do next? Thanks and happy holidays.

 

Replace the gas cap. I'm curious as to how you replaced the PCV valve because it's not serviceable and requires replacing the entire valve cover. The PCV lines would not cause that code anyways.

The only other thing I can think of that might be the problem is the check valve located near the right front strut tower not closing.