P0457 on Chrysler: How to Diagnose & Fix
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
1 Chrysler model · 1 documented issue · $40-$476 repair
P0457 on Chrysler by model: symptoms, diagnosis and fix
The Chrysler 300 uses Chrysler's proprietary natural-vacuum leak detection hardware instead of a conventional pressure-based leak detection pump. On 2005-2006 cars this is the NVLD (Natural Vacuum Leak Detection) valve/solenoid; from 2007 onward it is the ESIM (Evaporative System Integrity Monitor), a small spring-and-diaphragm switch mounted on or next to the charcoal/vapor canister on the left underbody ahead of the fuel tank. Both work the same way: as the sealed EVAP system heats and cools, natural pressure/vacuum changes trip an internal switch the PCM reads to confirm the system is sealed. The diaphragm seal inside the NVLD/ESIM is a well-documented high-failure item — it stiffens, sticks, or loses its seal with age, so the PCM can no longer verify integrity and falsely reports a leak. The result is a check-engine light with P0456 (small leak, ~0.020 in.), P0455 (large leak), or P0457 (interpreted as loose/missing cap), even when the fuel system is actually sealed. Because the code wording points at the gas cap, this is very commonly misdiagnosed: owners and shops replace the cap (and often the purge valve and canister) repeatedly before discovering the NVLD/ESIM itself is the culprit. One 2012 300 SRT owner reported eight dealer visits — the ESIM and its seal replaced twice, plus a new filler neck, purge valve, and charcoal canister — before the leak code was resolved. The fault is an emissions/MIL issue only: it does not affect drivability or engine longevity, but it will fail an emissions/smog inspection and on some model years can disable remote start until cleared. A faint fuel-vapor smell is occasionally reported when an actual leak is present.
Common Symptoms
- Check engine light / MIL on with no drivability change
- Stored EVAP leak codes P0455, P0456, and/or P0457
- Dashboard or message-center warning that the gas cap is loose/off even when it is tight
- Repeat check-engine light after replacing the gas cap
- Failed state emissions / smog inspection
- Remote start disabled until the code is cleared (some model years)
- Occasional faint fuel-vapor smell near the tank/filler when an actual leak is present
How to Fix
Always start with the cheapest checks: tighten the fuel cap fully (listen for clicks), inspect the cap's O-ring seal, and replace a cracked/old cap with a genuine Mopar cap, then clear the code and drive several drive cycles. If the code returns, have a shop perform an EVAP smoke test — but note the small-leak verification monitor can fail even when a smoke test passes (some hairline EVAP-line cracks only open under vacuum, sealing under the positive pressure of a smoke machine). Inspect the EVAP lines and the purge valve/solenoid for cracks. If the cap, lines, and purge valve are good, replace the NVLD valve (2005-2006) or the ESIM (2007+); the ESIM is the common Mopar service part (e.g., P/N 4861959AD), typically about $40-$60 OEM ($20-$50 aftermarket), and unbolts from the canister with a few hand tools — a DIY-friendly job. On early cars where the NVLD/ESIM is integrated and sold only with the charcoal canister assembly, expect a higher parts cost. After replacement, clear the codes and complete the EVAP drive-cycle/monitor before re-testing for emissions. Total at a shop generally runs from roughly $150 (ESIM swap with labor) up to the $417-$476 range if a full vapor/charcoal canister assembly is needed.
Sources for this issue (1)
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 Chrysler?
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 Chrysler it is documented across 1 model: 300.
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 Chrysler?
Published repair estimates on Chrysler range from $40 to $476 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.
Looking for P0457 on a different make?
View P0457 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.