P0301 on MINI
Cylinder 1 Misfire Detected
P0301 on MINI vehicles indicates cylinder 1 misfire detected. Au7o has documented this code across 5 MINI models — most commonly on Cooper, Cooper S, Coupe. P0301 means the engine computer detected a misfire specifically in cylinder 1 — the spark didn't ignite the fuel properly, or the fuel/air mix didn't burn as it should. The computer detects this by sensing tiny variations in crankshaft speed each time a cylinder fires. A misfire wastes fuel, raises emissions, and can damage the catalytic converter if it's severe or persistent (a flashing check engine light usually warns of active, converter-damaging misfires). Because the code points to one specific cylinder, the cause is usually an ignition, fuel, or compression problem isolated to that cylinder. Typical repair costs on MINI range from $300 to $3,000, depending on the specific model and root cause.
Common Causes of P0301
- •Worn or fouled spark plug in cylinder 1
- •Failed ignition coil or coil pack for cylinder 1
- •Faulty or clogged fuel injector for cylinder 1
- •Vacuum or intake air leak affecting that cylinder
- •Bad spark plug wire (on applicable engines)
- •Low compression (worn rings, leaking or burnt valve, head gasket)
- •Carbon buildup on intake valves
- •Wiring or connector fault to the coil or injector
P0301 on MINI by Model
MINI Cooper(1 issue)
- N12/N16 Timing Chain Tensioner Failure2007-2013
The R56 Cooper's N12 and N16 engines suffer from premature timing chain tensioner and guide rail failure. The plastic chain guides deteriorate, causing chain slack that leads to rough running, rattling on startup, and potential catastrophic engine damage if the chain jumps timing.
MINI Cooper S(2 issues)
- N14/N18 Turbo Engine Timing Chain Catastrophic Failure2007-2013
The R56 Cooper S N14 engine (2007-2010) is particularly notorious for timing chain tensioner failure, even more so than the naturally aspirated N12. The higher cylinder pressures from turbocharging accelerate chain stretch and guide rail wear. The revised N18 (2011-2013) improved but didn't fully resolve the issue.
- Direct Injection Carbon Buildup on Intake Valves2007-2025
All turbocharged direct-injection MINI engines (N14, N18, B46/B48) accumulate carbon deposits on intake valves since fuel is injected directly into the cylinder rather than washing over the valves. This reduces airflow and causes rough running.
MINI Coupe(1 issue)
- N14/N18 Timing Chain Tensioner Failure and Chain Stretch2012-2015
The MINI Coupe uses the N14 (early JCW) or N18 (Cooper S) turbocharged engines which are prone to timing chain stretch and tensioner failure. The plastic chain guide rails wear prematurely, and the hydraulic tensioner loses its ability to keep the chain taut. A stretched chain causes rough idle, misfires, and eventually can jump teeth, causing catastrophic valve-to-piston contact. The N14 is more prone than the N18 but both are affected.
MINI GP(1 issue)
- Carbon Buildup on Intake Valves (Direct Injection) Causing Misfires/Power Loss2013-2021
Direct-injection turbo engines in MINI GP models can accumulate carbon deposits on intake valves because fuel does not wash the valve backs. Over time this can cause rough idle, hesitation, misfires, and reduced performance, especially noticeable on cold starts. This is widely documented in MINI owner reports and service bulletins covering DI drivability complaints on N18/B48 platforms.
MINI John Cooper Works(1 issue)
- Intake Valve Carbon Buildup from Direct Injection2008-2024
All MINI JCW models with direct injection (both N14 and B48 engines) accumulate carbon deposits on the intake valves because fuel is injected directly into the cylinder rather than washing over the valves as in port injection engines. Over 30,000-50,000 miles, carbon buildup restricts airflow, causing rough idle, misfires, reduced power, and poor fuel economy. The N14 engine (2008-2012) is particularly susceptible due to its higher oil consumption contributing additional oil vapor to the intake tract.
Looking for P0301 on a different make?
View P0301 across all makes →Frequently Asked Questions
What does P0301 mean on MINI?▼
P0301 stands for "Cylinder 1 Misfire Detected." P0301 means the engine computer detected a misfire specifically in cylinder 1 — the spark didn't ignite the fuel properly, or the fuel/air mix didn't burn as it should. The computer detects this by sensing tiny variations in crankshaft speed each time a cylinder fires. A misfire wastes fuel, raises emissions, and can damage the catalytic converter if it's severe or persistent (a flashing check engine light usually warns of active, converter-damaging misfires). Because the code points to one specific cylinder, the cause is usually an ignition, fuel, or compression problem isolated to that cylinder. On MINI specifically, this code is documented across 5 models.
What causes P0301 on MINI vehicles?▼
Common causes on MINI: Worn or fouled spark plug in cylinder 1, Failed ignition coil or coil pack for cylinder 1, Faulty or clogged fuel injector for cylinder 1, Vacuum or intake air leak affecting that cylinder, Bad spark plug wire (on applicable engines). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0301 on a MINI?▼
Repair costs on MINI range from $300 to $3,000, depending on the specific model and root cause.
Which MINI models have P0301 documented?▼
Au7o has documented P0301 on 5 MINI models: Cooper, Cooper S, Coupe, GP, John Cooper Works.