Code P0456 Evap system

Hey there,

So, my 2014 Summit with around 62K miles decided to light up the check engine sign yesterday, and guess what? It’s throwing the P0456 code - evap system (very small leak). The “very” in the code description adds a nice touch of reassurance, doesn’t it?

I swung by O’Reilly’s and got a generous 10-sheet printout detailing all about this code and its potential causes. Seems like the most common (and thankfully cheapest) culprit is usually the gas cap. But, here’s the kicker - I’ve got a capless tank. Anyone else dealt with this error in a similar setup?

Now, my filler neck door has always been a bit on the loose side, and I’m starting to wonder if that might be playing a part here. Looks like the surefire way to know for sure is a smoke test from a mechanic, but given the holiday season, it might take a while before I can squeeze in an appointment.Hey there,

So, my 2014 Summit with around 62K miles decided to light up the check engine sign yesterday, and guess what? It’s throwing the P0456 code - evap system (very small leak). The “very” in the code description adds a nice touch of reassurance, doesn’t it?

I swung by O’Reilly’s and got a generous 10-sheet printout detailing all about this code and its potential causes. Seems like the most common (and thankfully cheapest) culprit is usually the gas cap. But, here’s the kicker - I’ve got a capless tank. Anyone else dealt with this error in a similar setup?

Now, my filler neck door has always been a bit on the loose side, and I’m starting to wonder if that might be playing a part here. Looks like the surefire way to know for sure is a smoke test from a mechanic, but given the holiday season, it might take a while before I can squeeze in an appointment.

I’m sorry to hear about the trouble with your Jeep. Dealing with the check engine light can be a hassle. It sounds like you’ve done your homework already, which is great!

Since you’ve got a capless tank, the usual culprit of a loose or faulty gas cap might not be the issue here. Your suspicion about the filler neck door being loose could be valid. Sometimes, even the smallest discrepancies in these systems can trigger the check engine light.

While waiting for a mechanic’s appointment, you might want to try a few things to see if the issue resolves itself.
Firstly, double-check that the filler neck door is securely closed. Sometimes, a simple adjustment can make a difference. Additionally, you can inspect the surrounding area for any visible signs of damage or wear that might be contributing to the leak.

However, if the light persists or if you notice any other unusual symptoms, it’s best to get it checked out by a professional as soon as you can. A smoke test from a mechanic will provide clarity on the situation.

Hey there. Hope you managed to fix your vehicle.

I know it’s a bit odd to reply this late.
But for the purpose of people who might stumble on this info.

The p0456 error especially on the Cherokee occurs when there’s a fault in the car leading to a small evaporative emission system leak.

Usually, the causation agents are

  • a loose or damaged gas cap
  • a cracked or damaged EVAP system hose
  • a faulty EVAP canister

In your case, you are correct it is a problem with the filler neck door, which can cause fuel vacuum leaks which will then make the check engine" light to turn on.