P0456 Code on Jeep: EVAP Small Leak Causes, FCA Bulletins, and Repair Cost

This guide explains how your Jeep tests for small leaks, the causes in the order to check them, the FCA bulletins for the Grand Cherokee and Wrangler, real repair costs, and whether it is safe to drive. Bulletin details come from FCA and Stellantis documents filed with NHTSA.

If your scanner also shows a large leak code, read our P0455 code guide. For a similar EVAP code on a Toyota, see our P0441 Toyota guide. And our free VIN decoder confirms your Jeep’s exact model year and engine, which decides which bulletin applies.

What Does P0456 Mean on a Jeep?

FCA’s own bulletins stress one important point: “P0456 is only set with multiple engine off and drive cycles, which cannot be reproduced during a dealer visit,” and “a road test will not confirm the repair.” Dealers are told to run a special scan tool test, the Small Leak Verification Test, before and after any repair.

How Your Jeep Tests for Small Leaks

Jeep has used three leak detection designs over the years, according to MOTOR Magazine and Vehicle Service Pros:

• Leak detection pump (LDP), from 1996: a small pump pressurizes the system and checks that it holds. FCA bulletin 25-001-02A covers LDP small leak codes on the 2002 Grand Cherokee.
• Natural Vacuum Leak Detection (NVLD), from about 2002: a sealed unit with a switch that closes when the cooling fuel tank pulls a slight vacuum after you park. If the switch does not close after enough engine-off time, the computer sets P0456. Parts catalogs list NVLD units for 2005 to 2006 Wrangler and Grand Cherokee and 2004 to 2006 Liberty.
• Evaporative System Integrity Monitor (ESIM), from about 2007 and still in use: a small module on the charcoal canister with weighted valves and a vacuum switch. Parts catalogs list it for 2007 and newer Wrangler, 2011 and newer Grand Cherokee, Cherokee, Compass, Patriot, Renegade and Gladiator.

On ESIM systems, the computer first watches for a natural vacuum after shutdown. If that test is not clear, it opens the purge valve to pull a vacuum and measures how quickly it fades. Vehicle Service Pros notes that a small leak code is only set after the large and medium leak tests have run.

P0456 Symptoms

• Check engine light with P0456 stored. For most owners, this is the only sign.
• A failed emissions inspection while the light is on.
• A fuel smell in some cases. FCA bulletin 18-035-20 links a disconnected vapor hose on 2020 Grand Cherokees to fuel odor near the left rear wheel.
• A “Check Gas Cap” message on some Wrangler 4xe models, which use fuel-tank-side codes P04EC and P04EE instead.
• The light coming and going, because the code needs several engine-off cycles to set.

Common Causes of P0456 on a Jeep (Check in This Order)

Fuel Cap, Filler Neck or Capless Filler

Start with the cheapest check. For 2021 Wrangler JL and Gladiator trucks built from June to October 2021, FCA bulletin 14-005-22 replaces the fuel cap. For 2020 Wrangler and Gladiator, an FCA technical note tells technicians to look for a damaged or misplaced cap o-ring and for gouges or chipped paint on the filler tube sealing surface. Many Grand Cherokees use a capless filler, and owners report that dirt on the flap can stop it sealing.

Loose Quick-Connects and Connectors

Some fixes need no parts at all. FCA notes cover a recirculation line quick-connect on 2020 to 2021 Wrangler JL, a fuel vapor hose that came disconnected on 2020 Grand Cherokee 3.6L models built from November 2019 to March 2020, and a connector with spread or pushed-out terminals on 2019 to 2020 Wrangler.

Split or Cracked Purge Hose

For 2015 Grand Cherokee 3.6L and 5.7L models built from November 16, 2014 to January 17, 2015, FCA bulletin 25-002-15 replaces a split purge valve hose, with a labor time of just 0.2 hours. On older Jeeps, look for brittle or cracked plastic and rubber lines under the hood.

ESIM or NVLD Switch and Seal

The leak detection module is a common replacement on Wranglers and Grand Cherokees, but it is not always the real fault. FCA guidance says that if the problem is in the ESIM detector and not the canister, “only replace the ESIM Detector.” Vehicle Service Pros advises confirming it by elimination after a smoke test and a switch test. In November 2025, Stellantis told dealers to stop using some ESIM parts packaged before September 4, 2025, so ask for a new-stock part.

Purge Solenoid

A leaking purge valve can play a part, but RepairPal notes that a purge or vent valve fault usually sets another code as well, not just P0456.

Fuel Filler Tube

FCA bulletin 14-007-23 covered a leak at a weld on the vapor recirculation tube of 2023 Grand Cherokee 3.6L models built on or before November 26, 2022, though a 2024 update made it information only. For 2021 Wrangler 4xe, bulletin 14-004-22 replaces the upper filler tube and cap as a pair.

EVAP Canister, Vent Filter and Software

A restricted vent filter or a flooded canister can also cause EVAP faults. FCA says the EVAP filter should be checked on the schedule in the owner’s manual, and offers a customer-paid dual filter kit for dusty use. Many engine computer software updates for the Wrangler JL, Grand Cherokee and Gladiator also list P0456, so ask a dealer whether your Jeep has an update available.

FCA Service Bulletins for P0456 on Jeep

We searched NHTSA’s records for every Jeep model from 2002 to 2025. There is no Jeep safety recall, emissions recall or warranty extension for P0456. The bulletins below tell dealers the known fix for specific builds.

What About the Jeep Wrangler JL Recall?

Many owners search for a “P0456 Jeep Wrangler JL recall.” There is no P0456 recall. Separately, FCA emissions recall 16C (revised August 2026) covers about 32,600 2018 to 2022 Wrangler JL and 2020 to 2022 Gladiator vehicles where the check engine light may not work correctly. It is worth checking your VIN for it.

P0456 on the Jeep Grand Cherokee and Wrangler

P0456 on the Jeep Grand Cherokee

On the 2011 and newer Grand Cherokee, check the capless filler, the purge hose under the hood and the ESIM on the canister. Look up bulletins for your build date: 25-002-15 for early 2015 models, 18-035-20 for early 2020 3.6L models and 14-007-23 for early 2023 models. Several software updates for 2013 to 2019 models also list P0456.

P0456 on the Jeep Wrangler

On the Wrangler JL and Gladiator, start with the fuel cap and the filler neck sealing surface, then the quick-connects and connectors, then the ESIM. Many 2018 to 2019 Wrangler JL software updates list P0456, including one as recent as June 2026, so ask a dealer to check yours. On the older Wrangler JK, owners report cracked EVAP lines as a cause.

How Much Does It Cost to Fix P0456 on a Jeep?

These are RepairPal estimates checked in September 2026, before taxes and fees. RepairPal does not list a separate price for the ESIM module; Vehicle Service Pros puts the part at around $20.

How to Diagnose P0456 on a Jeep

• Check the cap or capless filler. Tighten the cap, inspect the o-ring and the filler neck for gouges or chips, and clean a capless flap.
• Look up bulletins and updates by VIN, using the table above as a starting point.
• Inspect the hoses and connections: the purge hose under the hood, quick-connects near the tank and the ESIM connector.
• Smoke test the system. Vehicle Service Pros suggests adding smoke at the ESIM fresh air vent hose. FCA warns that a filler neck adapter used in place of the cap can hide a leak at the cap, so test with the original cap installed when you can.
• Test the ESIM switch. Vehicle Service Pros describes about 4.5 to 5 volts with no vacuum, dropping to about 0 volts under purge vacuum.
• Check the vent filter for dirt or restriction.
• Replace the ESIM only after the tests, then have the dealer confirm the repair with the Small Leak Verification Test if the light returns.

Can You Drive With a P0456 Code?

Usually, yes, for a short time. A very small vapor leak does not normally affect how the engine runs, but your Jeep will fail an emissions inspection, and a lit check engine light can hide a new, more serious fault. If you smell fuel, have it checked promptly.

P0456 vs Other Jeep EVAP Codes

• P0455: “EVAP System Large Leak,” often a loose cap or disconnected hose.
• P0457: loose fuel cap, set when the computer also sees a large change in fuel level.
• P0441: purge system performance, a purge flow problem rather than a leak.
• P0442: small leak on older leak detection pump systems.
• P0452 and P0440: ESIM switch faults on newer Jeeps.
• P04EC and P04EE: large and very small leaks on the fuel tank side, used on the Wrangler 4xe.

How to Prevent P0456

• Tighten the fuel cap until it clicks, and keep the capless flap clean.
• Stop filling at the first click of the pump.
• Have the EVAP vent filter checked on schedule, more often if you drive off road or on dusty trails.
• Check your VIN for FCA updates once a year.

The Bottom Line

P0456 on a Jeep is a very small EVAP leak and usually a cheap fix. Check the cap or capless filler first, then the hoses and connectors, and test the ESIM before replacing it. Look up the FCA bulletins for your build date, because they often name the exact part.

Related guides: trouble code guides by make.

Morgan Reyes

Morgan Reyes is the Lead Automotive Journalist and EV Analyst at Next Car Review. Specializing in mechanical systems and next-generation electric vehicles, Morgan breaks down complex automotive data, legacy matchups, and upcoming model previews into practical insights for car buyers.