P0456 on MINI: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Very Small Leak)
1 MINI model · 1 documented issue · $180-$650 repair
P0456 on MINI by model: symptoms, diagnosis and fix
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.
Common Symptoms
- Hard start after refueling
- Rough idle or stumbling
- Fuel smell near engine bay
- Occasional stall at idle
- Check Engine Light with EVAP-related codes
How to Fix
Replace the EVAP purge valve (tank vent/purge solenoid as applicable by engine) and inspect EVAP lines for cracks or disconnections. Clear codes and verify proper purge operation with scan-tool activation tests; ensure the fuel cap and filler neck seal correctly.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine MINI GP2 fuel-tank breather valve 13907624542OEMMINI 13907624542
Confirm VIN and ho
- Genuine MINI GP3 fuel-tank breather valve 13907621174OEMMINI/BMW 13907621174
VIN-confirmed 2020-2021 F56 GP3/B48E purge-valve stuck-open or failed-command branch Fitment/availability: The inspected direct U.S.
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P0456 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 P0456 mean on a 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 it is documented across 1 model: GP.
What are the most common causes of P0456?
The most common causes of P0456 are: 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. The specific cause varies by vehicle.
How much does it cost to fix P0456 on a MINI?
Published repair estimates on MINI range from $180 to $650 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 P0456 on a different make?
View P0456 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.