Why is the misfire only on cylinder 6?

A single-cylinder misfire code is the ECU telling you that one specific cylinder is contributing to crankshaft acceleration less than its neighbours. The cause is almost always something localised to that cylinder: its coil, plug, injector, or valves, rather than a problem that would affect the whole engine.

Can I drive with cylinder 6 misfiring?

Only as far as the nearest workshop, and ideally with a tow if the check engine light is flashing. A persistent misfire pumps unburned fuel into the catalytic converter, which can overheat and fail. Catalyst replacement is usually the most expensive part of fixing an ignored misfire.

Where is cylinder 6 on a V6 or inline-6?

On an inline-six (BMW N52, N54, N55, B58) cylinder 6 is the last cylinder, at the rear closest to the bulkhead. On a V6 it is always on bank 2, but where it sits depends on the maker's numbering: on engines numbered one bank first (Ford, Audi, Mercedes) it is the last cylinder of bank 2, while Toyota's 2GR V6 alternates sides and has cylinders 2, 4 and 6 on bank 2, the front bank on a transverse Camry. Check a wiring diagram for your engine.

Should I replace all the coils if only cylinder 6 failed?

Not necessarily. Moving the cylinder 6 coil to another cylinder shows whether the coil itself is faulty. If it is, look at the age and condition of the others: on an engine with original coils at high mileage they have run the same hours in the same heat, so replacing them together can save a repeat visit, while on a younger engine, or where oil got into one plug well, replacing the single coil is enough.

P0306: Cylinder 6 Misfire Detected

Quick Answer

Not safe to drive

P0306 means the ECU has detected repeated misfires on cylinder 6. Because cylinder 6 only exists on engines with six or more cylinders, this code is found exclusively on inline-6, V6, V8, and larger configurations. Common culprits are an ignition coil or spark plug specific to cylinder 6, a clogged injector, or in rarer cases compression loss in that cylinder.

Severity: High · Misfire
Estimated repair cost: From €38 to €2300+, varies by vehicle

Scan your own car in about 60 seconds: see whether P0306 is really what it has, how urgent it is, and what the fix should cost. Free on iPhone and Android with an ELM327 adapter (Bluetooth LE on iPhone).

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What does P0306 mean?

P0306 is a misfire-related diagnostic trouble code classified as high severity. When your vehicle's ECU detects this condition, it stores P0306 and illuminates the check engine light.

What are the symptoms of P0306?

If your vehicle has triggered P0306, you may notice one or more of these symptoms:

Check engine light on or flashing
Noticeable rough idle and vibration through the seats
Loss of power, especially under load
Increased fuel consumption
Possible fuel smell from the exhaust

What causes P0306?

Here are the most common causes of P0306:

Failed ignition coil on cylinder 6
: high
Worn or fouled spark plug on cylinder 6
: high
Clogged or leaking fuel injector on cylinder 6
: medium
Vacuum leak near cylinder 6 intake runner
: medium
Low compression on cylinder 6 (valve or ring wear)
: low

Is it safe to drive with P0306?

No - address this immediately. A persistent single-cylinder misfire dumps unburned fuel into the catalytic converter, which can overheat and fail. If the check engine light is flashing, stop driving and have the vehicle recovered to a workshop.

How do you diagnose P0306?

Follow these steps to pinpoint the root cause of P0306:

Read freeze-frame data and look at RPM, load, and coolant temperature when the misfire was logged. Cold-only misfires often point to fuel; hot-only misfires often point to ignition coils heat-soaking
Swap the ignition coil from cylinder 6 with a coil from a healthy cylinder. Clear codes and drive. If the misfire follows the coil, replace it
Remove the cylinder 6 spark plug and inspect for wear, fuel fouling, oil deposits, or a cracked porcelain. Replace any plug that looks suspect
Listen to the cylinder 6 injector with a stethoscope. A weak or absent click points to electrical or mechanical injector failure
Perform a compression test on cylinder 6 and compare to the others. A difference of more than 10% indicates an internal engine issue requiring deeper inspection

How much does P0306 cost to fix?

Repair costs for P0306 vary depending on the root cause and your vehicle. Here are typical estimates:

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Replace spark plug (cylinder 6)	€8–€30	€30–€120	€38–€150	Easy
Replace ignition coil (cylinder 6)	€40–€180	€30–€150	€70–€330	Easy
Clean or replace fuel injector (cylinder 6)	€60–€250	€100–€350	€160–€600	Professional
Cylinder head or valve repair	€200–€800	€400–€1500	€600–€2300	Professional

Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.

Full repair guides

P0306 on specific vehicles

P0306 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

P0306 on BMW

BMW 3 Series

See BMW-specific causes & cost

P0306 on Mercedes-Benz

Mercedes C-Class

See Mercedes-Benz-specific causes & cost

Audi

Audi A6

2011-2024

C7 A6 with the 3.0 TFSI supercharged V6 can set P0306 from a cylinder 6 coil, spark plug or injector fault. Swap the coil first, then check the injector, which on this direct-injection engine is refitted with new combustion seals.

P0306 on Toyota

Toyota Camry

See Toyota-specific causes & cost

These codes are often seen alongside P0306 or indicate related issues:

Common questions about P0306

Why is the misfire only on cylinder 6?: A single-cylinder misfire code is the ECU telling you that one specific cylinder is contributing to crankshaft acceleration less than its neighbours. The cause is almost always something localised to that cylinder: its coil, plug, injector, or valves, rather than a problem that would affect the whole engine.
Can I drive with cylinder 6 misfiring?: Only as far as the nearest workshop, and ideally with a tow if the check engine light is flashing. A persistent misfire pumps unburned fuel into the catalytic converter, which can overheat and fail. Catalyst replacement is usually the most expensive part of fixing an ignored misfire.
Where is cylinder 6 on a V6 or inline-6?: On an inline-six (BMW N52, N54, N55, B58) cylinder 6 is the last cylinder, at the rear closest to the bulkhead. On a V6 it is always on bank 2, but where it sits depends on the maker's numbering: on engines numbered one bank first (Ford, Audi, Mercedes) it is the last cylinder of bank 2, while Toyota's 2GR V6 alternates sides and has cylinders 2, 4 and 6 on bank 2, the front bank on a transverse Camry. Check a wiring diagram for your engine.
Should I replace all the coils if only cylinder 6 failed?: Not necessarily. Moving the cylinder 6 coil to another cylinder shows whether the coil itself is faulty. If it is, look at the age and condition of the others: on an engine with original coils at high mileage they have run the same hours in the same heat, so replacing them together can save a repeat visit, while on a younger engine, or where oil got into one plug well, replacing the single coil is enough.

Read our detailed guides

Scan your car with Skanyx to diagnose P0306

Your car logged P0306. Skanyx reads it on a standard OBD2 adapter (Bluetooth LE on iPhone), tells you whether it is safe to keep driving, and shows the €38-€2300 repair range so you know the number before a shop quotes you. Free on iPhone and Android, and you do not need to be a mechanic to read it.