P0306 on a Honda: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

If the check engine light is flashing, stop driving — a severe misfire can damage the catalytic converter. A steady light is usually safe for a short drive to a shop.

What P0306 means on a Honda

On a Honda, P0306 means the engine computer detected that cylinder 6 is misfiring, so that cylinder is not burning its fuel properly. Honda V6 engines use coil-on-plug ignition, so each cylinder has its own coil and plug, which points the fault at cylinder 6's own parts. If the light is flashing, the misfire is severe and can damage the catalytic converter.

Is P0306 common on Hondas?

P0306 appears on Honda V6 models like the Accord, Odyssey, and Pilot, most often as the 3.5L engine accumulates miles. Ignition coils and spark plugs are the usual wear items, and the rear bank coils sit tight against the firewall, which makes them a common failure point on the J-series V6. Injector problems and engine wear are less common causes.

Commonly reported on: Accord, Odyssey, Pilot, Ridgeline.

Symptoms

Check engine light on (flashing if severe)
Rough idle or vibration while idling
Loss of power or hesitation under load
Poor fuel economy

Common causes

most common: Failing ignition coil on cylinder 6
common: Worn or fouled spark plug in cylinder 6
common: Clogged or leaking fuel injector on cylinder 6
less common: Wiring or connector issue at the cylinder 6 coil
rare: Low compression in cylinder 6 from engine wear

How to fix it

Fix	DIY?	Typical cost
Replace the ignition coil on cylinder 6	Yes	$80–350
Replace worn spark plugs	Yes	$60–250
Replace or clean the cylinder 6 fuel injector	Mechanic	$150–400
Run a compression test to rule out internal engine wear	Mechanic	$100–200