Subaru Error Code P0305: How to Fix It

Q: What causes Subaru P0305 cylinder 5 misfire code?

Common causes include worn spark plugs, faulty ignition coils, clogged fuel injectors, vacuum leaks, low compression due to worn rings or valves, and damaged wiring harnesses. In Subaru H6 engines, ignition coils are a frequent failure point.

Q: Can I drive my Subaru with a P0305 code?

You should avoid driving with an active misfire as it can damage the catalytic converter and cause further engine problems. If you must drive, keep speeds low and get to a repair facility immediately. Extended driving with a misfire can result in expensive catalytic converter replacement.

Q: How much does it cost to fix P0305 on a Subaru?

Repair costs vary depending on the cause. Spark plug replacement costs $100-200, ignition coil replacement runs $150-300, fuel injector cleaning or replacement costs $200-600, and internal engine problems can cost $1500-4000 or more depending on the extent of damage.

Q: How do I know if it's the spark plug or ignition coil causing P0305?

The best way is to swap components between cylinders. Move the cylinder 5 spark plug to another cylinder, and move the ignition coil to another cylinder. Clear codes and run the engine. If the misfire follows the component to its new location, that component is faulty.

Q: Will P0305 cause my Subaru to fail emissions testing?

Yes, an active P0305 code will cause your vehicle to fail emissions testing. The misfire affects combustion efficiency and can damage the catalytic converter, both of which impact emissions. The code must be resolved and the vehicle must complete a drive cycle before it will pass emissions testing.

Abstract

Subaru error code P0305 indicates a misfire detected in cylinder 5, specifically affecting H6 engines found in models like the Outback, Legacy, and Tribeca. This code means the engine control module has detected that cylinder 5 is not firing properly, which can cause rough idling, reduced power, and potential engine damage if left unaddressed.