The Quick Answer above is the generic definition. What follows is what is documented for the BMW models that log P0301, checked against manufacturer data and owner reports.
DTC/P0301·BMW
P0301 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
High SeverityNot safe to driveBMW
P0301 on a BMW means the engine computer has counted repeated misfires isolated to cylinder 1, the first cylinder in the firing order. Combustion in that cylinder is incomplete or absent, so the engine runs rough and loses power. The most common cause by far is a worn cylinder-1 spark plug or a failed ignition coil. A replacement plug costs only 10-40 EUR, so start there before chasing fuel or compression faults.
Repair cost on BMW€40 - €1700
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BMW 3 Series
2006-2024The N54, N55, and B58 turbo engines are well known for ignition coil and plug wear. Cylinder 1 sits at the front of the engine and runs hot under the turbo plumbing, so its coil often fails first. BMW workshops typically replace all spark plugs around 60,000 km and coils as a set when one fails. Carbon buildup on the intake valves of the direct-injection N54 can also misfire cylinder 1 over time.
What causes P0301 on a BMW?
Beyond the generic causes listed on the main P0301 page, these are the documented BMW-specific patterns:
BMW 3 SeriesCylinder-1 ignition coil failure from underbonnet heat soak on N54/N55/B58
BMW 3 SeriesCarbon buildup on the cylinder-1 intake valves on direct-injection N54/N55
How to diagnose P0301 on a BMW with OBD2
Follow these steps to pinpoint the root cause of P0301:
- Read freeze-frame data to capture RPM, engine load, and coolant temperature at the moment the misfire was logged, which narrows cold-start versus load-related faults
- Swap the cylinder-1 ignition coil with the coil from cylinder 2, clear the code, and drive. If the misfire moves to cylinder 2 (now P0302), the coil is the fault
- Remove and inspect the cylinder-1 spark plug for electrode wear, carbon fouling, oil, or an out-of-spec gap. Compare it side by side with a plug from a healthy cylinder
- Confirm the cylinder-1 injector is clicking with a noid light or stethoscope, and check its resistance and wiring connector for an open or corroded pin
- Run a compression test on cylinder 1 and compare to its neighbours. More than a 10 percent drop, or a low reading that rises after adding oil, points to rings or valves
- Smoke-test or spray-test the cylinder-1 intake runner for a vacuum leak, and scan live fuel trims for a lean correction that tracks that cylinder
How much does P0301 cost to fix on a BMW? (EUR)
Estimated repair costs for P0301 in EUR, compiled across makes. Expect BMW parts and labour towards the upper end of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0301 on BMW
These codes commonly cluster with P0301 on BMW vehicles:
Looking for the full P0301 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0301 guideSkanyx · BMW
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