Check gas cap message

[Grrut]

I've been dealing with my cel light on for a while now. 456 I think is the code. Something about small leak, purge flow issue and gas cap. I bought a new cap and put it on at the parts store and started the truck and about 5-10 seconds later the check gas cap message and light went on. The cel was already on.
My question is, does it take a while for the check gas cap light to go out or should it go off as soon as the new cap goes on? Does it need to run and cycle a while?

 

[Gwerner74]

Needs to run and cycle for a while to clear, that is if the gas cap is indeed the problem. I'm dealing with the same issue on my 2015 2500. Gas cap wasn't the fix, ended up replacing the EVAP valve on the charcoal canister which cleared the codes, but also created a problem with filling the gas tank. I'll be digging deeper into this winter because I'm tired of swapping the EVAP valve in and out so I can pass inspection and also fill up the tank.

 

[EdGs]

On my 2015, it was the ESIM down by the tank. I believe it takes a few key cycles before the code will clear.

You can also have a crack in one of the lines, or even rodent damage, or possibly a bad purge valve.

 

[Grrut]

I'm going to get the purge valve along with a new cap. I returned the cap i bought yesterday after the light was still on, not knowing it needs to cycle for a while.
Is the purge valve on the engine or on the tank? I've seen both locations. I have a 15 big horn with 5.7 hemi

 

[Fergusontd]

My 2017 Ram Bighorn c-e-l comes on every so often it states a small evap emissions leak. I just use a code scanner and shut it off. My truck dosen't get run much (5900 miles).

 

[Grrut]

I disconnected the battery, installed the new gas cap and purge valve. Quite easy. Cel off, check gas cap message and light did not come on. We'll see what happens in a week or so. Thanks y'all

 

[Hanover Fiste]

My 2005 SLT has had that same code for several years now. If it doesn't shut itself off, I usually reset it. I've run a smoke test, and there is a small leak above the gas tank, but I haven't bothered to fix it yet. The truck runs fine otherwise.

 

[HarryS]

The ESIM is the likely suspect. It's not expensive, but a bear to replace.

 

[aszumilo]

My old 2004 had a check gas cap. Put on a new one from O'Reilly's. Code never went away. Reset it and came back a few days later. Went to the dealer and got an OEM cap. Light went out and never returned.

My, current, 2011 the light would come on at half a tank. Put an OEM on and still hasn't come back on for 20k + miles.

I will not use aftermarket caps ever again.

 

[Jigs-n-Fixtures]

The vapor recovery system pulls vacuum on the fuel tank and charcoal cannister to pull the captured vapors back out of the charcoal. If the system can't pull vaccum on the system, it triggers the fuel cap code and light. But, it can indicate a bad valve on the charcoal cannister, or just a loose vaccum line anywhere in the system. Defaults to fuel cap, because historically that is the most likely failure, and easy for an owner to fix.

 

[CaptOchs]

Mine was an ESIM. I replaced a few things before finding that. When I pulled the sensor and held it up to the light one of the leads was completely corroded in half. It wasn't too hard to replace. Just wanted a youtube video.

 

[slbenz600]

I've been dealing with my cel light on for a while now. 456 I think is the code. Something about small leak, purge flow issue and gas cap. I bought a new cap and put it on at the parts store and started the truck and about 5-10 seconds later the check gas cap message and light went on. The cel was already on.
My question is, does it take a while for the check gas cap light to go out or should it go off as soon as the new cap goes on? Does it need to run and cycle a while?

I have replaced 5 caps, 3 OEM, had two dealers smoke test and found nothing wrong. took to independent no luck. I can tell yo how to be able to fuel when it starts not accepting fuel, I think RAM should fix them ? I don't know if ths app save them, there have been a bunch and you know there are people that don't post.

 

[CaptOchs]

I have replaced 5 caps, 3 OEM, had two dealers smoke test and found nothing wrong. took to independent no luck. I can tell yo how to be able to fuel when it starts not accepting fuel, I think RAM should fix them ? I don't know if ths app save them, there have been a bunch and you know there are people that don't post.

Might not even be mechanical. The ESIM installed on the gas tank turned out to be my issue. The sensor has two pins. One corroded all the way though. I replaced with a new one and drove to the store and turned the truck off. When I started the truck again, the message cleared.

 

[Lee Pedrick]

I bought a locking gas cap from an auto parts store. Light kept coming on. Went and bought one from the dealership, the problem went away. Just my story.

 

[reefer451]

I just got a CEL yesterday on my 2014 1500 5.7L 4WD. It didn't display any messages. I checked the gas cap and it did seem loose so I cranked it down and kept running errands. It saw a number of starts and stops as I went to Walmart, grocery shopping, Walmart again (don't ask), etc. I thought the CEL might go away if the gas cap was the issue but it was still on when I drove to work this morning. So I grabbed one of our Autel scanners and it showed 3 instances of P0456 "Evap leak detected very small". One was listed as a "regular" code, one was "pending" and one was "permanent". I cleared the codes (the "permanent" one remained) and the CEL turned off. I wiped the gas cap and the filler with a rag although I didn't see anything on either. Took it for a 5 mile loop and the CEL stayed off.

I wanted to address this since I've got a long road trip coming up Friday-Monday. Now I know if the CEL comes back I can safely ignore it until I get home.

So what does it take to clear a code like this just with driving cycles? I'm sure there are a set number of cycles (3?) as well as criteria for meeting a cycle (time or temp met, cool down etc). Anyone have the specs?

 

[JJFW831]

just last week I had the same, replaced cap, non oem, code still there after a few days, replaced the purge valve on the engine and the vapor leak detection pump on the gas tank, and put my old oem gas cap back on, codes are gone. The vapor leak detection pump rattled like a baby rattle when shook, not suppose to do that, if it does that, it's bad. Simple replacement but a PITA, sorta. Both parts are not expensive. Kept the new purge valve on also.

 

[nascar72]

My 2005 SLT has had that same code for several years now. If it doesn't shut itself off, I usually reset it. I've run a smoke test, and there is a small leak above the gas tank, but I haven't bothered to fix it yet. The truck runs fine otherwise.

Same here with my '08 2500 hemi. Got codes 456-457 and "gascap" message. Got new gas cap but no luck. Also been getting gas smell on occasions when truck is parked. But yeah just like you, truck runs fine. I just live with it. My '03 did same thing at around same milage.

 

[Rambo71]

The squirrels love my ESIM. Replaced it twice. Had to order some Honda Rodent tape to stop the rascals!

 

[Deb P]

Needs to run and cycle for a while to clear, that is if the gas cap is indeed the problem. I'm dealing with the same issue on my 2015 2500. Gas cap wasn't the fix, ended up replacing the EVAP valve on the charcoal canister which cleared the codes, but also created a problem with filling the gas tank. I'll be digging deeper into this winter because I'm tired of swapping the EVAP valve in and out so I can pass inspection and also fill up the tank.

I replaced the ESIM (what you called the EVAP valve) on my 2007 1500 this morning, and I also had trouble with filling the gas tank later in the day. Trying to run a drive cycle as described in https://justsmogs.com/2014/01/chrys...rocedures-to-complete-obd-readiness-monitors/ , because I need to pass emissions. Replacing the ESIM did clear the CEL and codes.

Update: Getting the P0456 code again and the CEL is back on. I replaced the purge valve solenoid, took the truck on another early morning (4am) combined highway and stop and go, trying to complete a drive cycle. This is driving me nuts!

 

[Magfan2]

Had one on and off for a couple of years on a Dodge Magnum 5.7 R/T. Did and had done everything I could think of, and it would still happen. Turned out that I had the original battery 15 years on as original owner. Replaced the battery and the light never came on again. You have to look, but I found a reference online to battery as a potential cause.