FILLER CAP KEEPS MAKING A LIGHT ON DASH LIGHT

[AIRLORDD]

I have a 2017 ram heavy duty with 6.4 HEMI. I recently replaced the gas cap because there was a NON MOPAER unit on it when I bought the truck. Recently a warning comes up to say that I should check the gas cap. and leaves a caution light on the dash. I stop the truck and remove and replace the cap. I restart the truck and about 3 seconds later the message come up on the display then the little light comes on at the bottom of the dash. The cap is only abvout 1 month old and cant figure why Im getting this warning. any suggestions ????>?>?>?

 

[Dodge 1500 4X4]

Has it set off a CEL code, there is a ESIM module mounted on the tank that could be your problem, or possible purge valve mounted next to the throttle body, depending on the code I would get it smoke tested to verify your problem and don't use the parts cannon on it!!!

 

[AIRLORDD]

No CEL code but it does have a warning to Check the gas cap on the main screen that lasts about 5 seconds then puuts a light in the bottom of the center screen

 

[18CrewDually]

Was the light coming on before with the old cap? Put the old cap back on and see what it does.

 

[GTyankee]

go to an auto parts store & ask them to hook up their Scan tool, it does not cost anything, except your request.

Chances are it will be a p0456 or p0457 code, forget about the gas cap if it a Mopar cap, unless the gasket is ripped

 

[2003F350]

Was the light coming on before with the old cap? Put the old cap back on and see what it does.

This is what I would do. See if the issue goes away with the old cap, and if it goes away continue using the old cap.

I put a vented locking gas cap on my old '17, and never had any issues with codes or a 'check gas cap' message.

 

[El Guapo Phil]

I had a similar situation with my 5.7l Hemi. I could not figure it out. I did the gas cap swap. No change. Then I changed the pcvalve and (I can't remember the name of the other valve near the pcvalve). The lights went out after a few drives.

All was good and spent less than $20 on the parts. The two valve are easy to reach and swap out.

 

[AIRLORDD]

I changed the gas cap (even put the old cap back on) changed out the EVAP and the PURGE valves but the XCHECK FUEWL CAP keeps coming on. Does this take a couple cycles before the light goes away? or should it be immediate once the EVAP valve is changed out ? I think i followed all the recomendations that were providede but I still have the CHECK FUEL CAP light on.

 

[18CrewDually]

It will take a drive cycle to clear plus you need the tank to have 1/4 to 3/4 full tank of fuel for it to run a self test. I normally clear the MIL and then drive to see if it pops back on.

 

[AIRLORDD]

OK i will give it a drive cycle. the tank is 1/2 full right now so that should be good

 

[PA Ram]

Had similar issue on my old 2005 Ram 1500 and I replaced the gas cap and reset the light which would eventually come back. Had it to more than one shop and they couldn't figure it out and I needed it for a trip to North Carolina so I crawled under it and just looked for anything that could possibly be messed up. Well after a while I found a small diameter plastic tubing that was only held together by a sliver. It was a vent tube from the backside of the gas filler tube that connected at the other end to the gas tank via a quick release tab. Problem was that it was nearly impossible to reach. Took it to a shop and dealer and they told me the bed had to come off to access the end. Part was like $20 and the labor was ridiculous so I eventually somehow removed it and replaced it. It was chewed apart by a squirrel. Once I put the new tube on there it was good as new.

 

[GTyankee]

it may take a few ignition cycles, 5 or more

why the heck do they call it drive cycles
turn the ignition on & off has nothing to do with driving

When you change more than One Part at a time, it may fix the problem, but you may never find which part was bad.

I put my parts back in a box & date them, they may be good, like the Gas Cap or another part, like i have a few coils & voltage regulators in boxes, from vehicles i worked on years ago

 

[mcenz25]

Same problem for me. Dealer says I have a faulty fuel tank pump gasket.

 

[AIRLORDD]

So i changed out the gas cap, the evap pump and the purge pump . this morning I have a check engine light plus a fuel cap light,. the check engine light is a p0456. Any idea NOW ???? iVE DRIVEN THE VEHICLE TWICE SINCE I CHANGED EVERYTHING OUT. Does it take more times thyan that ?

 

[18CrewDually]

So i changed out the gas cap, the evap pump and the purge pump . this morning I have a check engine light plus a fuel cap light,. the check engine light is a p0456. Any idea NOW ???? iVE DRIVEN THE VEHICLE TWICE SINCE I CHANGED EVERYTHING OUT. Does it take more times thyan that ?

Had you cleared the codes and lights BEFORE the road tests? You should of to see if they come back.
If you did then you'll have to go further and look for cracked hoses or even if a mouse had chewed through a plastic line. (I've had that happen to a customer)
Below is an example of the hoses to check. Most shops would check it with a smoke machine and may show what you cannot easily see so best of luck.

 

[GTyankee]

AirLordd
drive it for a few more days
By then the trouble light will clear, or the problem may be the Purge Valve, ( which can be checked by blowing through it )

2013-2016 Ram 5.7 Hemi evap purge solenoid replacement

Please use the following link when ever using Amazon.com. Any purchases you make on Amazon will help support this channel.http://amzn.to/2mALgqSFeel the need...

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watch where this guy blows through the purge valve & the water bubbles, that shows the purge valve is bad.
air should not pass through

@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...

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down on the charcoal canister, there is a ESIM
It would be the 3rd thing to check.


you will find it on this, at the back of the fuel tank

 

[EastWestHemi]

Mine figured itself out after replacing the fuel cap, then leak detector, and finally the purge valve. My light turned back on after the purge valve but ended up being my 7 year old battery causing a voltage code. It was the purge valve all along. Took 20 minutes and cost $30 in parts. Like others say, do purge and fuel cap first… they are both cheap parts… leak detection valve last it’s was more expensive. I could barely blow through the purge valve, but that was enough. After the new battery my smooth idle came back. My gas cap gasket was shot after 7 years also.

 

[AIRLORDD]

Ive replaced the GAS CAP, THE PURGE VALVE AND THE EVAP VALVE (DOWN BY THE GAS TANK,) im still getting the check engine light with the p0456 code and the filler cap notice. Is there anything else i should be looking at before I take it to the dealer ?

 

[NETim]

Ive replaced the GAS CAP, THE PURGE VALVE AND THE EVAP VALVE (DOWN BY THE GAS TANK,) im still getting the check engine light with the p0456 code and the filler cap notice. Is there anything else i should be looking at before I take it to the dealer ?

I have NO first hand experience with this problem, but from what I've read here in a few threads, there's a vacuum line that runs from the gas tank to the engine that can go bad and cause this code.

And the general consensus is the fuel cap must be a MOPAR OEM fuel cap. Aftermarket caps can't always be relied on to seal properly.

 

[AIRLORDD]

SO I did some reading of other Ram trucks that had similar problems. one of the threads suggested that they remove the Negative battery cable and wait an hour. well I did this and guess what. all the lights and related stuff went away. Not saying that it fixed the problems but time will tell. I'll let you know in a couple of days if this fixed all the problems that replacing the parts like the gas cap, purge valve and the Evap valve were suppose to fix.