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P0456 - Evaporative Emissions System Leak Detected (very small leak)

Goatmann

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Check engine light came on yesterday. Once at my destination I checked for codes and the P0456 came up.

Checked out a few YouTube videos and found a few remedy’s. Could be a small hole in one of the evap system lines, could be a faulty purge solenoid, or a loose gas cap.

Seeing as it cannot be the gas cap I was wondering if anyone else with a 2019 may have experienced the same code and what was the repair.
 
On my old truck, it was always the purge solenoid and the NVLP
Also occurs from topping off your fuel tank when refueling, stop at the 1st click
 
It's not the gas cap per se that fails, but the seal. And while you don't have a gas cap, you do have seals. A stray blade of grass blown in could be enough to keep things from sealing tight.

I'd just erase the code and continue. If there is a real problem, it will set the code again.

Be aware that to run the EVAP monitor, the tank typically needs to be between 1/4 and 3/4 full. So don't expect to see any codes the day after a fillup. And also note that it has to run and fail twice in a row to set off the light.
 
@ Richard320, this is exactly what I plan to do. Was on my way to buy fuel, had a 1/4 of a tank when I saw the check engine light.
 
On small evap leaks, we use a smoke machine. It’s really hard to pinpoint small leaks, but that smoke machine will make the job easy.
 
Just got this code a day ago. Cleared it out and will see if it comes on again. They just replaced my starter at 38500 miles so not sure if something happened when they did that or if it’s unrelated. 2019 1500 Big Horn.
 
It will come back, I reset mine three times. about two weeks ago, (40,000 miles),I replaced the evap purge valve. $30 and 15 minutes was done. You do have to swap the rubber tube from the old unit to the new one.
 

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It will come back, I reset mine three times. about two weeks ago, (40,000 miles),I replaced the evap purge valve. $30 and 15 minutes was done. You do have to swap the rubber tube from the old unit to the new one.
So did this fix your issue? Or did the light come back on again?
 
Goatmann,
Are you saying buy the valve and hose or you were able to reuse the original hose?
 
You can buy a new hose if you want to, the unit does not come with the hose. Taking the hose off the old unit works great.
 
It will come back, I reset mine three times. about two weeks ago, (40,000 miles),I replaced the evap purge valve. $30 and 15 minutes was done. You do have to swap the rubber tube from the old unit to the new one.
Can you post the part number of evap purge valve? Thanks.
 
It will come back, I reset mine three times. about two weeks ago, (40,000 miles),I replaced the evap purge valve. $30 and 15 minutes was done. You do have to swap the rubber tube from the old unit to the new one.
How were you able to diagnose the part as the issue? I had the p0456 code appear for the second time now. For $30, it would not be the worst parts cannon job I have ever done, but still would like to confirm the issue.
 
How were you able to diagnose the part as the issue? I had the p0456 code appear for the second time now. For $30, it would not be the worst parts cannon job I have ever done, but still would like to confirm the issue.
See if it holds vacuum. Take the hose off and suck
 

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