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DTC/P0306

P0306: Cylinder 6 Misfire Detected

Quick Answer
Alta GravitàNon sicuro da guidareMancata accensione

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.

Costo di riparazione stimatoDa €38 a €2300+, varia in base al veicolo

Cosa significa P0306?

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.

P0306 è un codice diagnostico di guasto relativo a mancata accensione, classificato con gravità high. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0306 e accende la spia motore.

Quali sono i sintomi di P0306?

Se il tuo veicolo ha attivato P0306, potresti notare uno o più di questi sintomi:

  • 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

Cosa causa P0306?

Ecco le cause più comuni di P0306, ordinate in base alla probabilità che siano la causa del problema:

altaFailed ignition coil on cylinder 6
altaWorn or fouled spark plug on cylinder 6
mediaClogged or leaking fuel injector on cylinder 6
mediaVacuum leak near cylinder 6 intake runner
bassaLow compression on cylinder 6 (valve or ring wear)

È sicuro guidare con P0306?

No, risolvi subito il problema. 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.

Come si diagnostica P0306?

Segui questi passaggi per individuare la causa principale di P0306:

  1. 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
  2. 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
  3. Remove the cylinder 6 spark plug and inspect for wear, fuel fouling, oil deposits, or a cracked porcelain. Replace any plug that looks suspect
  4. Listen to the cylinder 6 injector with a stethoscope. A weak or absent click points to electrical or mechanical injector failure
  5. 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

Quanto costa riparare P0306?

I costi di riparazione di P0306 variano a seconda della causa principale e del tuo veicolo. Ecco le stime tipiche:

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace spark plug (cylinder 6) €8–€30 €30–€120 €38–€150 Facile
Replace ignition coil (cylinder 6) €40–€180 €30–€150 €70–€330 Facile
Clean or replace fuel injector (cylinder 6) €60–€250 €100–€350 €160–€600 Professionale
Cylinder head or valve repair €200–€800 €400–€1500 €600–€2300 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

P0306 su veicoli specifici

P0306 si comporta in modo diverso a seconda del tuo veicolo. Seleziona la tua auto qui sotto per cause specifiche del modello, problemi noti e stime dei costi adeguate:

BMW

P0306 su BMW 3 Series

2005-2024

The E90 330i with the N52 inline-six is famous for failing the cylinder 6 ignition coil first because of heat soak at the rear of the engine. BMW recommends replacing coils and plugs as a set at around 80,000 km. P0306 is one of the most common codes flagged on N52 in independent specialist shops.

Cosa causa P0306 su una BMW 3 Series?

BMW 3 SeriesCylinder 6 ignition coil heat-soak failure on N52 (rear position)
BMW 3 SeriesCylinder 6 injector wear on N54 twin-turbo

Costo di riparazione di P0306 per BMW 3 Series

Costi stimati per i proprietari di BMW 3 Seriesadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici BMW

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace spark plug (cylinder 6) €11–€42 €42–€168 €53–€210 Facile
Replace ignition coil (cylinder 6) €56–€252 €42–€210 €98–€462 Facile
Clean or replace fuel injector (cylinder 6) €84–€350 €140–€490 €224–€840 Professionale
Cylinder head or valve repair €280–€1120 €560–€2100 €840–€3220 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Mercedes-Benz

P0306 su Mercedes C-Class

2008-2018

W204 C350 with the M272 V6 commonly logs P0306 from a worn cylinder 6 ignition coil and a small vacuum leak at the rear of the intake manifold. The intake plenum has known cracking issues near the Bank 2 rear runner, which affects cylinder 6 most.

Cosa causa P0306 su una Mercedes C-Class?

Mercedes C-ClassCylinder 6 coil wear on M272 V6
Mercedes C-ClassIntake plenum crack near Bank 2 rear runner

Costo di riparazione di P0306 per Mercedes C-Class

Costi stimati per i proprietari di Mercedes C-Classadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Mercedes-Benz

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace spark plug (cylinder 6) €11–€41 €41–€162 €51–€203 Facile
Replace ignition coil (cylinder 6) €54–€243 €41–€203 €95–€446 Facile
Clean or replace fuel injector (cylinder 6) €81–€338 €135–€473 €216–€810 Professionale
Cylinder head or valve repair €270–€1080 €540–€2025 €810–€3105 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Audi

P0306 su Audi A6

2011-2024

C7 A6 with the 3.0 TFSI supercharged V6 sometimes triggers P0306 from cylinder 6 injector wear or a leaking supercharger coolant pipe in close proximity to the rear cylinders. The supercharger sits in the valley, so any leak above it tends to affect cylinders 5 and 6 first.

Cosa causa P0306 su una Audi A6?

Audi A6Cylinder 6 injector wear on 3.0 TFSI
Audi A6Supercharger coolant pipe leak biasing toward rear cylinders

Costo di riparazione di P0306 per Audi A6

Costi stimati per i proprietari di Audi A6adeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Audi

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Replace spark plug (cylinder 6) €10–€39 €39–€156 €49–€195 Facile
Replace ignition coil (cylinder 6) €52–€234 €39–€195 €91–€429 Facile
Clean or replace fuel injector (cylinder 6) €78–€325 €130–€455 €208–€780 Professionale
Cylinder head or valve repair €260–€1040 €520–€1950 €780–€2990 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Toyota

P0306 su Toyota Camry

2007-2018

Camry V6 with the 2GR-FE typically logs P0306 from a worn cylinder 6 coil or a clogged injector. The rear bank is harder to reach because the intake plenum and wiper cowl block access, so independent shops charge a bit more for V6 misfires than for the four-cylinder Camry.

Cosa causa P0306 su una Toyota Camry?

Toyota CamryCylinder 6 ignition coil failure on 2GR-FE
Toyota CamryCylinder 6 injector clog from poor fuel quality

Questi codici compaiono spesso insieme a P0306 o indicano problemi correlati:

P0300P0301P0302P0303P0304P0305P0171P0420

Domande frequenti su 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 most inline-6 engines (BMW N52, N54, N55, B58), cylinder 6 is at the rear, closest to the firewall. On V6 engines the location depends on manufacturer numbering: on BMW V6 it is the rearmost cylinder on Bank 2, on most Toyota V6 it is the rearmost cylinder on Bank 1. Check a wiring diagram for your engine.

Why does the BMW N52 fail cylinder 6 first?

On the N52 inline-six, cylinder 6 sits at the back near the firewall where heat soak is highest. The ignition coil over cylinder 6 routinely fails before the others. Mechanics replace it as a pair (cylinders 5 and 6) when they see the first failure to avoid a repeat visit.

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