P0456 on MINI
Evaporative Emission Control System Leak Detected (Very Small Leak)
P0456 on MINI vehicles indicates evaporative emission control system leak detected (very small leak). Au7o has documented this code across 1 MINI model — most commonly on GP. 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 MINI range from $180 to $650, 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 MINI by Model
MINI GP(1 issue)
- EVAP Purge Valve (Tank Vent Valve) Stuck Open Causing Rough Start and Fuel Smell2013-2021
MINI turbo models have documented EVAP purge/vent valve failures that can allow excess fuel vapor into the intake, causing hard starts after refueling, rough idle, and occasional stalling. Owners often report a fuel smell and drivability issues that are worse immediately after filling the tank. This issue is commonly referenced in MINI service literature and owner reports for N18/B48-era vehicles.
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What does P0456 mean on MINI?▼
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 MINI specifically, this code is documented across 1 model.
What causes P0456 on MINI vehicles?▼
Common causes on MINI: 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 MINI?▼
Repair costs on MINI range from $180 to $650, depending on the specific model and root cause.
Which MINI models have P0456 documented?▼
Au7o has documented P0456 on 1 MINI model: GP.