Check engine, code po456, evap emissions small leak

[Wmjohn]

I know gas cap is first thing to check, but how do you check a cap other than replacing it?

Interested to know what solutions others found for this code. I see some say esim $20-50, and some say purge valve.

 

[jws123]

I am chasing the same issue on my 2500 just change the cap its very cheap sometimes it fixes it mine lasted 3 months after a new cap before light came back on.

 

[GTyankee]

OEM Gas Cap is needed, if that is what is bad, so wait until last

Purge valve can be removed & using your lips & some lung pressure, you can tell if its bad, watch a youtube video,
so i say check it first

 

[Rayzaa]

Replaced the gas cap. Code still showed up. Replaced evap purge valve, code still showed up. Relaced cannister little pump thing(forget the name of it) and that solved it. Total spend was about $85. This was a few years ago. All easy to change.

 

[Wmjohn]

Can you kindly think of the cannister pump thing? Is it a pump? Im guessing its not the ESIM, is it?

I'd think mopar must have a diagram of all the parts somewhere...

 

[Rayzaa]

This is it. My Ram is a 2007 so your part may be different. Just google it.
I don't know what an esim is in relation to fuel EVAP system.

https://www.oreillyauto.com/detail/...15/automotive-truck-2007-dodge-ram-1500?pos=1

 

[GTyankee]

ESIM is no longer a pump, but they still call it that
ESIM is the Evap system integrity module

RAM TRUCK GAS CAP LOOSE P0456 P0457 HOW TO REPAIR

We fix the RAM TRUCK GAS CAP LOOSE Error P0457 and show how to repair this check engine light and issue on this ram1500 pickup truck with the 5.7L HEMI engin...

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[EdGs]

I had the same issue on my '15. Replacing the ESIM fixed it for me. I did buy a new OE gas cap first, as the o-ring on mine looked a bit funky, but that did not cure it.

 

[GTyankee]

It is seldom the gas cap, that is bad, which is also the most costly item, replace it last

The purge valve does not cost anything to test, that is why i would check it first, it is the mostly to be bad

ESIM is under the vehicle

 

[Rayzaa]

The had cap was the cheapest for me. Got it Amazon or eBay one of those.

 

[joelmic]

Sorry for the resurrection, no other post was more recent than this:

Had me a PO456 error, Bought the part on amazon but decided to CLEAN the gas cap.
It was very dirty and crusty. Used Goofoff on the whole thing, made sure the rubber seal was clean and had to really clean the metal good too. Got everywhere in the gas cap I could get, goofoff worked great.
Several starts after that and engine light went off.
I still have the EVAC pump part incase. But it's all good for now. Never got around to replacing it cuz of the COLD, didn't need it.

 

[Daw14]

Lots of people have said smearing the seal with petroleum jelly will help it to seal tighter ,and possibly get rid of the code.

 

[joelmic]

Lots of people have said smearing the seal with petroleum jelly will help it to seal tighter ,and get rid of the code.

I put a little Plumbers grease on it... it's made for seals and Orings and such

 

[Hanover Fiste]

I replaced every component in the system except for the plastic tubing (which is no longer available), and the error still appears on my '05. I just reset the code every time the error reappears, which is every 3 weeks or so.

 

[jws123]

I replaced every component in the system except for the plastic tubing (which is no longer available), and the error still appears on my '05. I just reset the code every time the error reappears, which is every 3 weeks or so.

did you smoke test the system?

 

[GTyankee]

you can buy or build a Smoke Machine

lot of videos about that subject

start with something like a standard sized Mayo or Jelly jar

By the way,
using anything but a MOPAR GAS CAP, could be the reason the code keeps coming back

 

[Hanover Fiste]

did you smoke test the system?

Yes, I did. I saw some smoke above the fuel tank, so I'm guessing I have a small leak there somewhere. I have no desire to drop the fuel tank or raise the bed, so I'll just keep resetting the light as necessary.