Cylinder 2 misfire on BMW — N20/N55/B58 ignition coil or N47 injector flow imbalance.
BMW P0302 — Cylinder 2 misfire on BMW — N20/N55/B58 ignition coil or N47 injector flow imbalance. Typical UK independent garage cost: £90–£850.
What actually causes P0302 on a BMW
BMW coil failures cluster — replace one and the next is days behind. On N47 diesel a cylinder-2 misfire is more often injector flow imbalance than electrical. Always swap a known-good coil/injector to cylinder 2 to confirm before condemning.
BMW engines that log P0302
- N20 2.0 TwinPower
- N55 3.0 single-turbo
- B58 3.0 TwinPower
- N47 2.0d
How we diagnose P0302 on a BMW
- Swap coil 2 with coil 1 — does the misfire follow?
- Read injector correction values on N47/N57 — high mg/stroke correction = injector
- Inspect plug condition — wet plug suggests injector
- Compression test if mechanical suspected
The common misdiagnosis to avoid
Spark plugs ignored — BMW recommends NGK/Bosch OE plugs at 40k on turbo petrol engines; cheap plugs cause misfires that look like coil failures.
BMW P0302 repair cost in the UK
Expect £90–£850 including parts and labour at an independent garage. Main-dealer quotes on BMW are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.
Bob's workshop tip
Never replace one BMW coil — fit a full set on petrol turbo. The next one fails within 5,000 miles and you'll do the labour twice.
Codes usually seen alongside P0302 on BMW
- P0301
- P0303
- P0304
- P0300
Symptoms drivers report with P0302
- The car feels like a 'kangaroos' when you're pulling away from traffic lights.
- A violent shudder or 'judder' specifically under heavy load, like climbing a hill in 4th gear.
- The engine light starts flashing—that's the car telling you the catalytic converter is melting.
- Lumpy idle that feels like the car is 'coughing' through the seat.
- A distinctive 'putt-putt' sound from the exhaust tailpipe when parked.
Repairs that clear P0302
- Replace plug & coil
- Injector test
For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0302 guide.
Reading P0302 on a BMW properly
A generic reader will show P0302 and nothing else. What matters is the freeze-frame data stored with it — engine speed, load, coolant temperature and fuel trims at the moment the fault was logged — plus whether any other module on the BMW has logged something at the same time. Codes rarely arrive alone, and the order they were stored in usually points at which one is the cause and which are the consequences.
Clearing P0302 without fixing it
Erasing the code resets the BMW's readiness monitors as well as the light. The fault returns on the next drive cycle if the cause is still there, and in the meantime the incomplete monitors can stop the car passing an emissions check. After a genuine repair, the car is driven until the relevant monitor completes before it is handed back.
Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P0302 is showing on your BMW, bring any scan results with you — we will read the live data ourselves, confirm which cause it actually is, and price the repair before any work starts.