Code P0456

[TalkeetnaDodge]

Hello. I recently acquired a well maintained 2012 Ram 1500 (5.7 Hemi) (91K) - a new type of vehicle for myself. Today I noticed a MIL light. Auto Zone checked and came back with a P 0456 code. I replaced the gascap. But reader was unkowledgeable on how to erase the code. Note: I haven't tried the battery (negative disconnect). This summer, I had driven the vehicle about 800 miles, no issues, starts ok, idles ok, accelerates ok , no vibrations, highway: 18-19 mpg; city 14-15. Yesterday, a winter tire changeover, a 120 mile trip, I filled the tank enroute - no light. Today in the city : the MIL. Also , the light that advises ECN doesn't illuminate, the avg gas mileage (numeric) readout is not consistent, however, (the seem to indicate the correct fuel flow per the appropriate condition). I have been reading previous posts and understand that the there could be numerous issues with in the evaporative system and it seems that the best method to troubleshoot is via a smoke test. My OBD is in another car miles away.

Before throwing parts at it via a shop, I wanted to ask if this type of Code can be reset via a battery disconnect and if not, can that only be done with a Dodge shop tool? Any comments will be appreciated.

 

[GTyankee]

p0456,
usually put the Gas Cap at the top of the list

The Purge Valve should be at the top of the list
it is under the hood, close to the throttle body

often a aftermarket fuel cap, will not work in a Ram truck

 

[Bigskyroadglide]

There is also a canister on top of the fuel tank that is suspect. Cost around $20 easy to replace.

 

[GTyankee]

that would be the ESIM up by the cannister

 

[TalkeetnaDodge]

As a 'newbie' to this vehicle, thanks. I stopped by another auto store and watched the clerk 'erase' the code on the OBD, but this action didn't extinguish the light. I will try the battery disconnect when the rain stops. I stopped by the Dodge Ram Dealer to inquire. They will troubleshoot that code with a smoke/leak detector ($200) and look at the 'normal' replacement type items, etc. (The clerk estimated low probability
for bad cap (which they can check) or poor gas. NOTE: Not so easy to DIY in AK in winter. A month to get an appointment. Fustrating not to be able to extinguish this type of code to see if transient or a 'loose' cap, when everything seems to run OK, otherwise.

Does anyone know, does the P 0456 affect fuel mileage (if just a tiny leak)? And how does the MIL light on affect the Economy mode readout.

 

[Daw14]

Give it some time ,it should go out after a certain amount of drive cycles.

 

[TalkeetnaDodge]

I am inclined to think that since I had fueled and then MIL illuminated the next day that it was a gas cap issue. I find it curious as to why it's troublesome to extinguish the light for the code 0456 and if there is some relation between whatever is going on and fuel economy (is economy mode also disabled or just the indicator). I haven't driven enough to be able to tell a difference.

 

[Daw14]

It’s been my experience,when a code is thrown my eco would no longer function.

 

[TalkeetnaDodge]

So far continuuing my education; having learned about evap system, fuel cap and tank design, MIL & ECo illumination. Disconnected the battery, one hr. during lunch, the MIL extinguished. ECO light and other MPG readings back to normal. Ordered an OBD so I don't have to go to Napa, Autozone, or O Reilley's (all helpful). Now wait and see if light comes back.

 

[David H]

since I had fueled and then MIL illuminated the next day

Something about over filling at fuel stops comes to mind. Seem to remember something about people experiencing these issues after topping off the tank (to excess).
Maybe someone can elaborate on this?

 

[markabby]

So far continuuing my education; having learned about evap system, fuel cap and tank design, MIL & ECo illumination. Disconnected the battery, one hr. during lunch, the MIL extinguished. ECO light and other MPG readings back to normal. Ordered an OBD so I don't have to go to Napa, Autozone, or O Reilley's (all helpful). Now wait and see if light comes back.

you can delete codes all day, or, every time they come on....it's not fixing the problem. My 2011 ram had a similar issue and it was a vacuum line from the top of the tank to the engine.

the reason mine went bad was as i was driving on I75, i had no choice but to run over a black plastic bag some one lost. Inside the bag was a blanket, and that wrapped around the driveshaft, which in turn ripped that hose off. My milage went down to 10-12 MPG...on the highway! UGH I fixed it by cutting off the bad ends and adding a hose to those ends. it worked..lol. About a year later i traded it in.

 

[62Blazer]

It's not hard to delete codes. If the engine light is still on did you verify it was for the same 0456 code or is there a different one?

To try to explain this without causing more confusion. Often when the MIL activates due to a code, the exact issue that triggered the code only occurred for a short period of time and went way. An example is the truck detects a misfire for a few seconds and then the misfire goes away. Even if the issue "went away" the MIL will stay active for some period of time on to let you know that something did happen. Clearing the code with a scanner will turn off the MIL light until the issue happens again.

There are also times when an issue occurs and continues to occur. Using the misfire example, the engine detects a misfire and it continually misfires anytime the engine is running. So the issue is still active. In this case you can clear the code and turn off the MIL, but as soon as you start the engine back up the MIL will come on again because it is detecting that the misfire is still present.

I believe, but not 100% certain, the P0456 will always be intermittent. Meaning if it comes on once and you clear the code, you can generally drive for some period of time before it activates again (won't get into drive cycle tests and the intervals between them). Based on that I would be somewhat surprised that is the only code was P0456, you cleared the code, but the MIL remained on.

 

[wallacemf]

I have p0456 on my 2018 Ram 2500 currently, for the third time. In my case, a squirrel or some other rodent keeps getting on top of the fuel tank and chewing on the plastic evap lines. We live in the country so it’s not uncommon. I just cut out the chewed section and splice in some vacuum line. This time I put on some braided stainless sheathing as well, hopefully it stops this nonsense.

 

[GTyankee]

P0456 Evaporative Emissions System - Small leak detected

Read more at: https://www.obd-codes.com/p0456
Copyright OBD-Codes.com

Almost every online repair site for trouble code p0456
has a trouble shooting guide list

usually at the top of the list, is Gas Cap

many people read that & run down to their local auto parts store
that very likely is a mistake
first of all, if there is something wrong with the cap, it would be an issue with the caps Seal

The Universal Gas Caps, when it comes to Rams, are not a sure thing.
Rams like Mopar Fuel Caps

Causes Usually this P0456 code is caused by an incorrect or faulty gas cap. Filling the fuel tank with the engine running could conceivable cause this code as well or if the cap wasn't properly tightened.
Any of the following could also be the cause:
A small leak in any of the EVAP hoses or fuel tank hoses
A small leak in the purge valve or vent valve , ( ESIM )
The EVAP Canister may be leaking


Now watch this video, this mechanic shows what should be checked

Causes and Fixes Dodge P0456 Code: Evaporative Emissions System - Small Leak Detected

How to fix a Dodge P0456 Code: Evaporative Emissions System - Small leak detectedVapor Canister Leak Detector on Amazon: https://amzn.to/3VPsvAUPossible Caus...

www.youtube.com

Something that he did not include:

You can easily check a Purge Valve
Once the purge valve is removed
Blow air through it, if you blow air through it
It needs to be replaced

@carservicepro P0456, how to test purge solenoid, EVAP leak, Dodge Ram EVAP leak

this for 2016 Ram 1500 Hemi, how to test purge solenoid leak off the vehicle, I just blow mouth air to confirm valve leak, code P0456 is for small leak detec...

www.youtube.com

 

[theskier74]

I've had this one for months. I was told most likely the ESIM cannister I just haven't gotten around to it. Honestly, I feel like this is a free way of an MDS delete so I've kind of just been rolling with it ‍ I live in a hilly area and going back and forth between eco mode is super annoying

 

[Justin33]

You are thinking about that wrong…your mph will suck but I don’t think that code is going to have anything to do with mds… ai have a small and large leak and can feel the truck lugging still

 

[04fxdwgi]

My wife's car had the same problem (she overfilled). I tried the gas cap and no joy. The fix was the vapor canister purge valve. Was a cheap / easy / fast fix.

They do go south if tank is over filled and it sucks raw fuel into the purge valve.

 

[Justin33]

My wife's car had the same problem (she overfilled). I tried the gas cap and no joy. The fix was the vapor canister purge valve. Was a cheap / easy / fast fix.

They do go south if tank is over filled and it sucks raw fuel into the purge valve.

Wait was it the part by the tank or the purge valve under the engine cover?

 

[chri5k]

Why does almost every thread about an EVAP leak recommend the parts cannon? And most every thread where someone has fired the parts cannon at some other problem say don't fire the parts cannon?

Smoke test machines can be had on Amazon for $75. They will help pinpoint the EVAP leak so one can fix the problem right the first time and probably cost about the same or less than the parts cannon. As an added bonus, one will have the machine for future problems or to help their friends and neighbors.

 

[Burla]

My wife's car had the same problem (she overfilled). I tried the gas cap and no joy. The fix was the vapor canister purge valve. Was a cheap / easy / fast fix.

They do go south if tank is over filled and it sucks raw fuel into the purge valve.

this would be my guess as well, there is a cost to topping off ten times, the juice aint worth the squeeze,