Hi All
2015 F150 120k miles, 1st time April 18 2024 got the code replaced the evap valve, all good, a few months later same code, replaced charcole canister, all good, Jan 26 2025 got code again and found evap valve was bad and under warrenty, replaced all good, Today. wife got the code again. I have done all the work myself. I am not home at the moment my wife checked the computer for me. if the eveap valve is good, possible fuel tank pressure sensor? I am pretty handy and dont want to spend $$$$ taking to dealer,
thanks

 

Your not looking at the Code description 144c, in depth.
It says, Ejector or Check valve is tested and fails under >>Boost conditions, for some reason.
The check valve is to prevent Boost pressure from pressurizing the fuel tank.
The fuel tank pressure sensor will detect pressure as too high.
This you don't want to happen or blow tank apart and leak fuel or fail EVAP testing.
Good luck.

 

Bluegrass is correct. Below may help.

 

UPDATE
I changed the Evap valve. although it seemed to have tested good. I did clear the check engine light but it came back at idle after about 10 seconds with a "YELLOW" light on the reader and no check engine light. drove 20 miles some town, some highway, some stopping, shut it off for about 30 min. drove 2o miles back to house same thing and no check engine light but my scanner still shows P144C but with a yellow light not a red one

 

To clarify, are we referring to the electronic solenoid controlled purge valve, or a basic mechanical check valve? Are the two round "drums" on the assembly check valves?
I'm seeing an intermittent P144C which started popping up a few months after replacing the purge valve assembly. Original purge solenoid valve was stuck open. Replaced with an O'Reilly's Standard Ignition unit. Wondering if the new assembly is suspect.

 

.
Review reply #2 that explains the code.
Look at reply #3 to see where in the piping it is located.
The code failure is telling you the check valve (in that path) is not sealing > UNDER BOOST conditions< only, to keep Boost Pressure from passing into the fuel tank.
Good luck.

 

Good Morning All
All good now. replaced the purge valve assy that comes with the built in check valve. no more code and just got done driving 200 plus miles. thank you all for the help and that schematic is now printed and in my computer..thank you very much. Awesome forum

 

Hey could you tell me what purge valve assembly you bought that fixed the code? Maybe the part number at Oreilly’s? Been dealing with a p144c and seem to be in a similar boat as you. Thanks!

 

NAPA part number 994-140, was 100 and change. Hope this helps. Just drove another 200 miles back to home today and no code still.

 

Thank you so much!! I’m praying you have a great and blessed night!