Gas cap fuel/engine light is on

[CaseO]

I changed out the cap and the engine light is still on. How do I turn or reset the engine light? Thank you

 

[Rlaf75]

More than likely there's an EVAP code stored. If you don't have a scan tool to hook up and check the codes then go to your local auto parts store and have them check the code and clear it. They will usually do it for free. After they clear it, drive it like normal for a week and see if the code comes back. If it does not then you're good. If it does come back then you need to start diagnosing the EVAP system for a leak somewhere.

 

[Burla]

Unhook the battery, turn car on/off a few times, let it go out on it's own, all possible fixes with this cel.

 

[Burla]

Mine went out just by ignoring it 1 mile trip.

OB2 have a clear function, you don't have an ob2? I paid like 20 bucks for mine, nothing special, but deletes and clears codes. Pays for itself the first fix.

 

[GTyankee]

did you use a MOPAR CAP ?

Next thing to check is called the PURGE VALVE
You can check it without spending money
Remove the large air hose, the one that goes from the air filter to the Throttle body.
remove the purge valve, unless you have an small air compressor.
In the video, at the 7 minute point, they tell you how to check the Purge Valve using some air pressure

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...

www.youtube.com

 

[EdGs]

My '15 did that to me, new gas cap did not fix. Ended up being the leak detection pump.

 

[2017PowerRam]

I know this is an old thread, but thought I'd attach notes and pictures.
Had codes P0456 & P0457 for small evaporative emissions leaks. New gas cap and new purge valve did not fix the problem.
I followed the directions from the factory shop manual. GTyankee above linked video was helpful.

Negative Battery Cable: remove, 10 mm long socket, 6 inch extension, 3/8 stub ratchet. Cover the connector with a sock.
Jacked up the back of the truck. I had nine teeth showing on the jackstands and had them under the frame at front of spring mount.

I was able to access the pump by crawling under the truck and sitting up on the passenger side of the differential in front of the axle.
Electrical connector: press down clip that faces right and remove
Hose: twist to break loose from fitting on old pump and remove
OEM Pump: left-hand to press release clip at the bottom toward the rear of the truck. Turn the pump 1/8 turn counterclockwise with the same hand. Remove pump. Pump mechanism is loose and housing. Rattles around with no anchor point. I think we have found what is causing the diagnostic trouble code for small evaporative emissions leak. OEM on right in 1st picture and at top in second picture.

Large O-ring gasket: remove. It sits right at the edge of the mounting circle. Rag to wipe the O-ring gasket mounting area.
Dorman O ring: press in the position.

Dorman 310 – 219 leak detection pump: I turned it to about 4:30 PM, pressed hard against the o-ring gasket with my left hand. Turned the pump 1/8 turn clockwise with my left hand in front of the pump and my right hand on top of the pump. Felt mounting area and inspected gasket area to make sure the rubber O-ring gasket stayed seated.

Hose: press on fitting at pump
Electrical Connector: press into female connection at pump until the clip clicked in place.

Remove truck from jackstands
Negative Battery Cable: install, 10 mm long socket, 6 inch extension, 3/8 stub ratchet
Thus far, P0456 & P0457 codes have not come back. Thanks everyone for all the info!

 

[RedSRT4Me]

This problem comes and goes for me. I do nothing and it eventually goes away.

Truthfully though I changed all the suggested items in the past. None of it has an effect immediately. It usually takes so many key cycles before the light goes off on its own.