P0456 Code

[62Blazer]

Hopefully you got it fixed. The P0456 code is for a small evaporative leak of the fuel system and can be caused by numerous different things.
I would never, ever randomly throw parts at a vehicle based on what some person at Autozone stated. No offense to anybody that works there, but from my experience most of them have very little mechanical knowledge. On top of that somebody simply reading a code and telling you start throwing parts at it should not be listened to either. I almost always look up the actual part number I need and order based on that, versus jumping through the hoops to tell them what color the car is when ordering an oil filter.
I would also hope people might consider looking at something else if the issue was not fixed after replacing the same part multiple times. Sure, you might get a bad part one time and need to replace it (just because it's new doesn't mean it's good) but getting 2 bad parts in a row is not that common.
In regards to when the code comes on, it's pretty common to have long delays in re-activation of this code after being cleared. There is a whole series of "tests", or drive cycles, that need completed prior to a light engaging. And for many codes it would have to fail multiple tests before the ECM finally triggers a check engine light.

 

[briantmustang]

I have a 2018 dodge 2500 6.4 with a p0456 light and I smoked tested it and replaced the gas cap and the esim and I still get the p0456 and the gas cap light coming on. what else can it be?

 

[Rayzaa]

Hopefully you got it fixed. The P0456 code is for a small evaporative leak of the fuel system and can be caused by numerous different things.
I would never, ever randomly throw parts at a vehicle based on what some person at Autozone stated. No offense to anybody that works there, but from my experience most of them have very little mechanical knowledge. On top of that somebody simply reading a code and telling you start throwing parts at it should not be listened to either. I almost always look up the actual part number I need and order based on that, versus jumping through the hoops to tell them what color the car is when ordering an oil filter.
I would also hope people might consider looking at something else if the issue was not fixed after replacing the same part multiple times. Sure, you might get a bad part one time and need to replace it (just because it's new doesn't mean it's good) but getting 2 bad parts in a row is not that common.
In regards to when the code comes on, it's pretty common to have long delays in re-activation of this code after being cleared. There is a whole series of "tests", or drive cycles, that need completed prior to a light engaging. And for many codes it would have to fail multiple tests before the ECM finally triggers a check engine light.

True, i didnt consult them. I had that code as well and just started from the beginning and the cheapest part.
Gas cap from Amazon didn't fix it, purge valve from O'Reillys didn't fix it. The esim from same auto parts store fixed it.
Total cost about $85

 

[EastWestHemi]

Father in laws truck has this code still to this day. Smoked at a semi trust worthy dealer and found that something is cracked or broken on top of the gas tank where lines and stuff connect. Supposedly needs a new gas tank because nothing is serviceable. What a PITA. I shared a post awhile back on it. He doesn’t have $1500 sitting around throw a new gas tank under it, bad design IMO, truck is a 2016 with 80k miles. I hope it doesn’t happen to mine.

 

[JerryETX]

I have a 2018 dodge 2500 6.4 with a p0456 light and I smoked tested it and replaced the gas cap and the esim and I still get the p0456 and the gas cap light coming on. what else can it be?

So I went through several ESIM’s before buying a Mopar part and that makes a difference. This last time for me it was the purge valve. I ordered one online and it took me about 10 minutes to replace it and that’s only because I don’t have good eyes and was being careful. It’s more like a 5 minute job for most.

 

[Rayzaa]

Doesn't matter if it's a Mopar part or not. You have to replace the problem part which was the purge valve. Mine was the esim but I did the gas cap & purge valve first doing process of elimination.

 

[JerryETX]

Doesn't matter if it's a Mopar part or not.

Not true. I replaced the ESIM 3 times with Auto Zone parts and all 3 times were temporary fixes that didn’t work. I installed a Mopar ESIM and light went off and no issues until the purge valve went bad. I talked to a Jeep mechanic as well as the dealer and both said at least for the ESIM OEM matters

 

[Rayzaa]

Not true. I replaced the ESIM 3 times with Auto Zone parts and all 3 times were temporary fixes that didn’t work. I installed a Mopar ESIM and light went off and no issues until the purge valve went bad. I talked to a Jeep mechanic as well as the dealer and both said at least for the ESIM OEM matters

That's because according to you, the problem ended up being the purge valve and wasn't the main problem. It was likely on its way out as well.
Me I started w/ a gas cap and then purge valve which didn't fix it. Mine ended up being the esim, didn't use Mopar part.

Later on I needed a new oil pressure sensor and didn't use a Mopar part and it's fixed.

 

[JerryETX]

That's because according to you, the problem ended up being the purge valve. You could of put a Mopar esim in it and it wouldn't have fixed it.

I didn't use any Mopar parts and mine was fixed when I put in a new part that was the problem.

Later on I needed a new oil pressure sensor and didn't use a Mopar part and it's fixed.

To clarify it was between a week and two weeks from when I installed the Mopar ESIM and the check engine light went off to when the light came on again and I replaced the purge valve. I’m glad the aftermarket parts are working for you. I should’ve said not always true. In my case the Mopar ESIM clearly solved at least a 6 month long issue of going through aftermarket ESIM’s.

FYI- your aftermarket parts aren’t going to last as long as OEM parts, generally. Age also comes with learning and knowledge and I have learned that buying aftermarket parts is stepping over a dollar to save a dime. That’s of course my opinion.

 

[Rayzaa]

To clarify it was between a week and two weeks from when I installed the Mopar ESIM and the check engine light went off to when the light came on again and I replaced the purge valve. I’m glad the aftermarket parts are working for you. I should’ve said not always true. In my case the Mopar ESIM clearly solved at least a 6 month long issue of going through aftermarket ESIM’s.

FYI- your aftermarket parts aren’t going to last as long as OEM parts, generally. Age also comes with learning and knowledge and I have learned that buying aftermarket parts is stepping over a dollar to save a dime. That’s of course my opinion.

We'll see. It's been 2 years. Imo they are the same, they just slap another name on it. Has the same part number.

I mean you have to figure, it's Mopar parts that are failing and are common issues.