P0305 means the ECU counted enough missed combustion events on cylinder 5 (typically over 2% of firings in a 200-rev window) to trip the misfire monitor. Expect rough running and a flashing CEL under load.
Scan your own car in about 60 seconds: see whether P0305 is really what it has, how urgent it is, and what the fix should cost.
Download SkanyxP0305 means the ECU counted enough missed combustion events on cylinder 5 (typically over 2% of firings in a 200-rev window) to trip the misfire monitor. Expect rough running and a flashing CEL under load.
P0305 is a misfire-related diagnostic trouble code classified as high severity. When your vehicle's ECU detects this condition, it stores P0305 and illuminates the check engine light.
If your vehicle has triggered P0305, you may notice one or more of these symptoms:
Here are the most common causes of P0305:
No - address this immediately. You can limp home, but a sustained misfire dumps raw fuel into the catalytic converter and can destroy it within a tank or two. Fix it before your next commute.
Follow these steps to pinpoint the root cause of P0305:
Repair costs for P0305 vary depending on the root cause and your vehicle. Here are typical estimates:
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Full repair guides
P0305 behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:
N54 and N55 inline-sixes chew through Bosch coils and NGK index plugs.
The narrow-angle VR6 uses six individual coil packs on a single head. Original brown coils (VW p/n 06B905115) were superseded by updated units after widespread failures.
These codes are often seen alongside P0305 or indicate related issues:
Yes, and it's the fastest free test you can do. Move the cylinder 5 coil to cylinder 1 or 3, clear the code, and drive. If P0301 or P0303 pops, the coil is bad. If P0305 comes back, the coil is fine and you're looking at plug, injector, or mechanical.
Yes, and quickly. A flashing CEL means raw fuel is hitting a red-hot cat. A sustained misfire can destroy a converter in a few hundred kilometres, turning an €80 coil job into a €600-€1500 cat replacement.
On most transverse V6s and longitudinal V8s, cylinder 5 sits at the rear of the head where heat soak from the firewall or exhaust is worst. Coils cook faster there. On inline sixes it's simply the second-hottest position. It's not random - rear cylinders live a harder life.
Cold-only misfires usually point to a coil breaking down when secondary resistance is highest, a cracked plug insulator arcing to ground, or an injector that's slow to open cold. Warm-only misfires more often mean a heat-sensitive coil or a compression issue that seals up as the head expands.
Move to the fuel and vacuum side. Check injector resistance (typically 12-16 ohms on port injection), listen with a mechanic's stethoscope for the click, and smoke-test the intake. If all that's clean, run a compression and leakdown test before spending more on parts.
An ignition coil fires the spark plug, and when it weakens the engine misfires. What the coil does, why it fails, the codes that name the cylinder, and the cost.
A flashing check engine light is not the same as a steady one. It almost always means an active misfire that can wreck your catalytic converter in minutes.
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Your car logged P0305. Skanyx reads it on any standard Bluetooth OBD2 adapter, tells you whether it is safe to keep driving, and shows the €45-€2700 repair range so you know the number before a shop quotes you.
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