Persistent Check Engine Light - 6.4L

Hey folks so I've got an interesting (read annoying) problem going on for about the last month. My check engine light came on over the New Year holiday and because the dealer was closed I swung by Advance Auto to have them read the code for me so I could figure out if the truck was ok to drive for a couple days. They said small evap leak so I tightened the gas cap, had them clear the code, and went on with my life. Fast forward about a week and the light comes back on. This time the dealer is open so I head straight there. Their machine showed evap system fault and I leave the truck with them to diagnose. They tell me the evap canister is leaking and order the part. There's a whole bunch of drama around this that's not really related so I'll leave it out for brevity. The relevant part is that the part was going to take over a week to arrive and they told me the truck was fine to drive so I drove it around for over a week with the CEL on per their assurance that it was fine. Eventually, they get a new evap canister in the truck and I pick it up. I get about 3 miles down the road and the CEL comes back on. I turn right around and head back to the dealer. Their system was showing no new codes, just a stored code for the evap leak. They clear it again and I'm on my way. The light stays off this time for about 65 miles and then comes back on. I take it back and the same story, no new code just the stored evap code that they supposedly cleared last time. It's back at the dealer today, I told them I don't want it back until they can figure out what the problem is and how to make the CEL go off for good.

So my question to you all, anyone had a CEL that keeps coming back due to a stored code? Could there be something else going on that isn't reporting correctly? Any thoughts on what I can get the dealer to do that may make this problem go away once and for all? It's been in a total of 4 times now for this and I'm tired of wasting my time going back every few days.

That does not sound right. Once cleared, the return of the CEL indicates a problem exists.

Check your gas cap.

Honestly, unless they didn't get the hose on the evap cannister on correctly, or there is a crack in a hose, it may be that your gas cap seal is bad. Check it.

Thanks MadDog! When they call me today I'll tell them to check the gas cap seal and to make sure all the hoses are tight and not cracked. I hate that dealers are generally so incompetent we all have to spend our own time on the internet troubleshooting issues for them but I'm sure glad I have this place as a resource. So much good information and so many helpful people. I honestly didn't even think to tell them to make sure all the hoses are good and the gas cap seal is good.

Well, just spoke with the dealer and apparently it actually is a new code that wasn't showing up on the computer they use at check in. The new code is no longer evap system leak now it's evap purge system performance, whatever the hell that means. So now I keep waiting to find out what's actually wrong and what they're going to do to fix it.

It's related but in that instance I would look at the valve in the system and do a vacuum test.

Good luck!

Thanks once again for the info MadDog! I should be hearing from them in a couple hours or so with an update. We'll see what they say. This truck is like a misbehaving child right now; I still love it but damn do I want to smack it right now. Been dealing with this for most of the month

I have a persistent CEL too. Evap related. I had it in a couple of times. They fixed it, and I went on my way. That was an 4057 code I think. Now I have the 4056 code. It's related, but I haven't had the time to take it in. It clears itself from time to time. It was off for like 4 days the other day. It was a record.

Had that on my Jeep. Finaly found a cracked hose that was part of the evap system. once fixed drove 20 miles on the highway Engine light never came back on after that. Look at a diagram of the evap system and run it all down or have a smoke test done it. My bet it is a leak in the evap system.
MK

Had same issue the two days after buying the truck new (2014 6.4l) Smoke tested found nothing so cleared the code just to come back on. After 2 or 3 trips to dealer it ended up being the fuel tank pressure sensor.

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2015 ram sport with about 23,000 miles. I've had the CEL come on a couple times over the last year. I forget the codes thrown, but they were small evap leak realted ones. The first time a code was thrown last year, i took it to a dealer and was told not to worry about it, its not a major problem, just an evap leak and they cleared it. About 6 months later it came back again. Since that one, its come back two more times. I have my own OBD scan tool now and just clear them, but i'm now on my 4th CEL in the last 12 months, so i am about to bring it in again for a real inspection. I hope they dont try to blow it off as a tiny issue and not to worry about it.

joneseysr6 said:

2015 ram sport with about 23,000 miles. I've had the CEL come on a couple times over the last year. I forget the codes thrown, but they were small evap leak realted ones. The first time a code was thrown last year, i took it to a dealer and was told not to worry about it, its not a major problem, just an evap leak and they cleared it. About 6 months later it came back again. Since that one, its come back two more times. I have my own OBD scan tool now and just clear them, but i'm now on my 4th CEL in the last 12 months, so i am about to bring it in again for a real inspection. I hope they dont try to blow it off as a tiny issue and not to worry about it.

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man, not even two days after clearing my last code ( 0456 small evap leak ), its came back again. Same code, 0456. Guess i'll be scheduling a drop off at my dealership sooner than i planned.

It's probably the purge valve they don't usually find it with a smoke test because it vents into the intake manifold

I got the truck back on Saturday and so far the light has stayed off. This time they replaced the purge solenoid. They smoke tested the system and said they found no more leaks. If it comes back again I'll tell them to just replace the valve and the gas cap and all the hoses and anything else that touches the system so I don't have to bring it back again lol.

joneseysr6 said:

man, not even two days after clearing my last code ( 0456 small evap leak ), its came back again. Same code, 0456. Guess i'll be scheduling a drop off at my dealership sooner than i planned.

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Hi joneseysr6,

Sorry to hear about this! I'd be happy to follow up with your dealership for you if needed, just PM our page with your VIN and let me know.

Andrea
Ram Social Care Specialist