P0305 on a BMW: 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 P0305 means on a BMW

On a BMW, P0305 means the engine computer detected a misfire on cylinder 5. On an inline-6 BMW, cylinder 5 is in the rear half of the engine, near the firewall. Because the code names one cylinder, the cause is usually that cylinder's ignition coil, spark plug, or injector.

Is P0305 common on BMWs?

P0305 is most common on BMW inline-6 models like the 3 Series, 5 Series, X3, and X5, and also appears on V8 models. BMW ignition coils are a well-known wear item and are the most common cause of single-cylinder misfires. Worn spark plugs come next on higher-mileage cars.

Commonly reported on: 3 Series, 5 Series, X3, X5.

Symptoms

Check engine light on (flashing if severe)
Rough idle or shaking
Loss of power or hesitation
Poor fuel economy

Common causes

most common: Failing ignition coil on cylinder 5
common: Worn or fouled spark plug on cylinder 5
less common: Clogged or leaking fuel injector
less common: Wiring or connector issue at the coil
less common: Low compression from engine wear

How to fix it

Fix	DIY?	Typical cost
Replace the ignition coil on cylinder 5	Yes	$90–280
Replace the spark plug on cylinder 5 (or all plugs)	Yes	$60–200
Replace or clean the cylinder 5 injector	Mechanic	$250–600
Run a compression test if the misfire returns	Mechanic	$100–200

Frequently asked questions

Where is cylinder 5 on a BMW inline-6?

It's near the back of the engine, closest to the firewall. That spot is why coil swaps on BMWs are a little more work than on other cars.

Why are ignition coils a common cause on BMWs?

BMW coil packs wear out with heat and mileage, and a failed coil is the top reason for a single-cylinder misfire code. Many owners replace all six at once.

Is it safe to drive my BMW with P0305?

A steady light is usually fine for short trips. A flashing light means a severe misfire, so stop and have it towed.