P0456 on Acura
Evaporative Emission Control System Leak Detected (Very Small Leak)
P0456 on Acura vehicles indicates evaporative emission control system leak detected (very small leak). Au7o has documented this code across 1 Acura model — most commonly on RDX. 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 Acura range from $40 to $150, 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 Acura by Model
Acura RDX(1 issue)
- Fuel Cap Gasket Fails to Seal Setting EVAP Large-Leak Codes P0455/P0456 (TSB 14-006)2012-2015
Second-generation RDX owners get a TIGHTEN FUEL CAP message and a check engine light for an EVAP leak, and the cap is tight. Acura issued service bulletin 14-006 covering the RDX and other Honda/Acura models: the original fuel cap's black gasket fails to seal reliably, so the EVAP system's leak monitor reports a leak that no amount of retightening will clear. Because the cap looks and feels fine, this is commonly chased with expensive smoke testing and purge-valve replacement before the cap is suspected. The EVAP fault will also block emissions-test readiness monitors.
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What does P0456 mean on Acura?▼
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 Acura specifically, this code is documented across 1 model.
What causes P0456 on Acura vehicles?▼
Common causes on Acura: 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 Acura?▼
Repair costs on Acura range from $40 to $150, depending on the specific model and root cause.
Which Acura models have P0456 documented?▼
Au7o has documented P0456 on 1 Acura model: RDX.