EVAP Help

Hello,

i have a 2013 base (regular cab) and have been having an EVAP (P0441, P0446) error for a couple of months that i have not been able to clear. started with the typical checking the gas cap, then replacing the gas cap, then replacing the solenoid. after that, i took it to my mechanic to do a smoke test etc. He thought the charcoal filter was bad so he replaced it and didn't find any leaks. at this point, the entire system has been replaced but the codes persist. what am i missing, has anyone had a similar issue? how have you resolved it? when i took it to my mechanic to replace the filter he wanted it to have less than a 1/4 tank of gas to make it easier to drop the tank, so each time i take it to him i try to have as little gas in it as possible (just in case) then typically after i pick it up it seems fine lights off, i drive to work the next day no lights, fill up on my way and when i come out of work at the end of the day the lights are back

Any thoughts or advice would be helpful...thank you

 

Do you ever overfill your gas tank? As in, when the pump shuts off you keep pulling the lever until it shuts off a couple more times. If you never do this and you always stop when the pump shuts off, then I doubt that the charcoal filter was was bad. Have you checked the purge valve solenoid?

 

https://youtu.be/C5s3Rx3wjD0?si=LF70EMBMTr5wHp-4

 

How many miles on the truck and plugs?

 

So if you replaced the evap purge solenoid and the canister it leaves hard lines and the fuel pump oring.

The place where most leaks occur is the fuel neck, corrosion can build up and eat the line causing a leak.

Basically you need a mechanic that can isolate the lines and test them for leaks.

 

I'm assuming you mean P0456 not P0446.

In order to properly leak test the system you have to plug the air inlet (vent) line coming from the Leak Detection Pump, closing the vent valve does not seal the system on this design EVAP system.

If you have a capable scan tool you can force an EVAP test and graph the PIDs to get an idea of the size of the leak.

 

The fuel tank pressure sensor should be checked too.

 

thank you all for your help so far, to answer a few of the questions, I used to top off my fuel but learned thru this process that it was a bad idea and have since stopped (before the canister was replaced) the truck has 158K, and I have not replaced the spark plugs since buying it about a year ago, not sure when they were last replaced. i am from Michigan, but I purchased a southern ruck to avoid many issues plaguing northern vehicles. not to say that corrosion can happen in the south