P0457 on Jeep: How to Diagnose & Fix
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
1 Jeep model · 1 documented issue · $20-$350 repair
P0457 on Jeep by model: symptoms, diagnosis and fix
The Jeep Grand Cherokee uses a Natural Vacuum Leak Detection (NVLD) approach for its EVAP system, implemented through the Evaporative System Integrity Module (ESIM) — commonly called the leak detection pump. The ESIM is a standalone unit (typically mounted on the charcoal canister near the rear driver-side wheel well) that seals the fresh-air vent and uses natural temperature-induced pressure changes to verify the fuel-vapor system holds vacuum. The internal seal/diaphragm and check mechanism in the ESIM are a well-documented common failure point on Chrysler/Jeep platforms. When the unit fails, the PCM cannot complete its EVAP self-test and falsely reports an EVAP leak, illuminating the check engine light even though no actual leak exists. Because the same codes are thrown by a loose or worn gas cap, the failure is frequently misdiagnosed: owners (and even shops) replace the gas cap first, the light returns, and the actual ESIM/leak-detection-pump fault is missed. A simple field test is to remove the ESIM and shake it — a rattle indicates the internal valve has come loose and the unit needs replacement. Note that a split EVAP purge-valve hose (TSB 25-002-15 Rev. A, 2015 3.6L/5.7L units built Nov 16, 2014 to Jan 17, 2015) and a disconnected fuel vapor hose in the left rear wheel well (TSB 18-035-20, 2020 3.6L units built Nov 4, 2019 to Mar 9, 2020) produce the same codes, so the hoses should be inspected before condemning the ESIM. This is an emissions-only fault: it does not harm the engine or transmission but will fail a state emissions/smog test.
Common Symptoms
- Check engine light on (often intermittent, may clear and return)
- OBD-II scan shows P0456 (small EVAP leak), P0455 (large EVAP leak), or P0457 (loose fuel cap / large leak)
- "Check Fuel Cap" / gas cap warning message
- Fuel/gasoline odor near the vehicle in some cases
- Failed state emissions or smog test
- Light returns shortly after a gas cap replacement (sign of misdiagnosis)
- Occasional slightly extended cranking
- ESIM rattles when removed and shaken (failed internal valve)
How to Fix
Diagnose before replacing parts. (1) Inspect/re-tighten or replace the gas cap and confirm it clicks and seals — rule out the cheapest cause first. (2) Visually inspect the thin plastic EVAP purge-valve hose on top of the engine for cracks/splits (especially at connection points) per TSB 25-002-15 Rev. A, and on 2020 3.6L units check the fuel vapor hose quick connector in the left rear wheel well per TSB 18-035-20; replace or reconnect as needed — this alone fixes many cases. (3) Locate the ESIM/leak detection pump (on the charcoal canister near the rear driver-side wheel well); remove and shake it — if it rattles, the internal valve has failed. On 2013-2016 models, FCA requires the EELD/smoke test and confirmation that PCM flash updates have been performed before the ESIM or canister is replaced. Replacement is a straightforward DIY: a new ESIM (OEM, or aftermarket such as Dorman 310-219) installs in place of the old one. After replacement, clear the codes and complete a few drive/fill cycles to confirm the EVAP monitor passes and the light stays off. If codes persist after ESIM and hose service, smoke-test the EVAP system to find a remaining leak (canister, lines, or fuel-tank-side seals).
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar purge hose for the 3.6L ERB bulletin branchOEMMopar 68189075AE
A repair after a split hose is confirmed on an in-window 2015 WK 3.6L ERB Fitment/availability: 68189075AE supersedes AC/AD and is cataloged for 2014-2015 Grand Cherokee 3.6L.
- Genuine Mopar purge hose for the 5.7L EZH bulletin branchOEMMopar 68189065AD
A repair after a split hose is confirmed on an in-window 2015 WK 5.7L EZH Fitment/availability: 68189065AD supersedes AB/AC and is cataloged for 2014-2015 Grand Cherokee 5.7L.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- WarningP0455/P0456 does not identify an ESIM, gas cap, canister, or hose by itself. Match the build window and inspect or smoke-test the system before buying a part.
- TipUse the VIN and engine sales code to distinguish the 3.6L and 5.7L purge hoses before ordering.
Sources for this issue (3)
P0457 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0457 mean on a Jeep?
P0457 stands for "Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)." This code means the engine computer detected a large leak in the sealed fuel-vapor (EVAP) system, most often traced to a loose, missing, or poorly sealing gas cap. The EVAP system is supposed to trap gasoline vapors and burn them in the engine instead of releasing them into the air; a big leak lets those vapors escape. It is an emissions-only fault that will not hurt the engine, though it triggers the check-engine light and can cause a faint fuel smell. On Jeep it is documented across 1 model: Grand Cherokee.
What are the most common causes of P0457?
The most common causes of P0457 are: Loose, missing, or improperly tightened fuel cap, Worn or cracked fuel cap seal/gasket, Damaged fuel filler neck or sealing surface, Cracked or disconnected EVAP hose, Stuck-open purge or vent valve, Faulty fuel cap that won't hold pressure, Leaking charcoal canister. The specific cause varies by vehicle.
How much does it cost to fix P0457 on a Jeep?
Published repair estimates on Jeep range from $20 to $350 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.