P0456 on Chrysler
Evaporative Emission Control System Leak Detected (Very Small Leak)
P0456 on Chrysler vehicles indicates evaporative emission control system leak detected (very small leak). Au7o has documented this code across 1 Chrysler model — most commonly on 300. This emissions code means the evaporative emission (EVAP) control system has detected a very small leak — even tinier than the one flagged by P0442, roughly equivalent to a 0.020-inch hole. The EVAP system traps fuel vapors from the tank and prevents them from escaping into the atmosphere, and the computer tests for leaks by sealing the system and watching for pressure or vacuum loss. Because the leak is so small, the cause is often subtle, but a loose or worn gas cap is still the most common and easiest to check. It generally indicates a minor seal, hose, or valve leak somewhere in the fuel vapor system. Typical repair costs on Chrysler range from $20 to $500, depending on the specific model and root cause.
Common Causes of P0456
- •Loose, worn, or faulty gas cap or cap seal
- •Cracked or loose EVAP hose or line
- •Leaking vent valve or purge valve not sealing
- •Damaged O-ring or seal at the fuel filler neck
- •Small crack or leak in the charcoal canister
- •Leaking fuel tank or sending unit gasket
- •Loose or corroded EVAP component connection
P0456 on Chrysler by Model
Chrysler 300(2 issues)
- EVAP System Small Leak (P0456)2011-2023
Evaporative emission control system develops small leaks triggering P0456 code. Most commonly failed gas cap, chaffed EVAP purge pipe harness, or failed purge solenoid. Triggers check engine light and prevents emissions testing pass.
- EVAP Leak Detection (NVLD/ESIM) Failure Triggers P0455/P0456 — Often Misdiagnosed as a Bad Gas Cap2005-2023
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.
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View P0456 across all makes →Frequently Asked Questions
What does P0456 mean on Chrysler?▼
P0456 stands for "Evaporative Emission Control System Leak Detected (Very Small Leak)." This emissions code means the evaporative emission (EVAP) control system has detected a very small leak — even tinier than the one flagged by P0442, roughly equivalent to a 0.020-inch hole. The EVAP system traps fuel vapors from the tank and prevents them from escaping into the atmosphere, and the computer tests for leaks by sealing the system and watching for pressure or vacuum loss. Because the leak is so small, the cause is often subtle, but a loose or worn gas cap is still the most common and easiest to check. It generally indicates a minor seal, hose, or valve leak somewhere in the fuel vapor system. On Chrysler specifically, this code is documented across 1 model.
What causes P0456 on Chrysler vehicles?▼
Common causes on Chrysler: Loose, worn, or faulty gas cap or cap seal, Cracked or loose EVAP hose or line, Leaking vent valve or purge valve not sealing, Damaged O-ring or seal at the fuel filler neck, Small crack or leak in the charcoal canister. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0456 on a Chrysler?▼
Repair costs on Chrysler range from $20 to $500, depending on the specific model and root cause.
Which Chrysler models have P0456 documented?▼
Au7o has documented P0456 on 1 Chrysler model: 300.