P0456 & P0457

[pacman89]

Hello,

I recently got these two codes. Have gone down the list of things to fix and am still having the issue. Even reset the check engine light every time but it keeps coming back.

Got a new gas cap
Swapped out the EVAP canister under the truck (by the gas tank)
Swapped out the EVAP Purge Valve in the engine bay

Does anyone know of what the next steps should be? This is driving me nuts. Thank you in advance.

 

[Rlaf75]

Next step is to take it to a reputable shop that can properly diagnose EVAP systems otherwise you'll just continue throwing money at it in hopes of finally fixing it. EVAP codes can be very difficult to diagnose without the proper equipment. A tiny leak in the system can be very hard to find without a smoke machine and the knowledge to use it. These codes don't necessarily mean a sensor is bad. It could mean there is a hole/crack in a plastic tube somewhere impossible to see which will make a sensor or valve get false information which with trigger the CEL. Without a smoke machine you'll never see the split in the line. Along with smoke, an advanced scan tool may be required in order to activate the sensors and purge valves which sometimes has to happen to induce smoke into the system. Or you can just keep buying and replacing things until you get lucky. Good luck

 

[Daw14]

Needs to be smoke tested , search this forum for others who have done this and how to accomplish the job.

 

[EdGs]

Does your truck have the ESIM on the rear of the tank assembly?