P0306 on a Volvo: 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 Volvo

On a Volvo, P0306 means the engine computer detected that cylinder 6 is misfiring, so that cylinder is not producing power on schedule. It appears on Volvo six-cylinder models like the S80 and XC90, which use one ignition coil per cylinder. A flashing light means the misfire is severe enough to risk catalytic converter damage.

Is P0306 common on Volvos?

P0306 shows up on Volvo six-cylinder models like the S80, XC90, and XC60 as the inline-6 engine accumulates miles. Ignition coils and spark plugs are the usual wear items. Fuel injector issues and low compression are less common causes on these engines.

Commonly reported on: S80, XC90, XC60, S60.

Symptoms

Check engine light on (flashing if severe)
Rough idle or shaking 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: Vacuum leak from a cracked intake hose
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	$90–350
Replace worn spark plugs	Yes	$80–300
Replace or clean the cylinder 6 fuel injector	Mechanic	$200–500
Run a compression test to rule out internal engine wear	Mechanic	$100–250