how to fix P0304 code on my Volvo XC60 First Generation (2008-2017)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Volvo XC60. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the battery to ensure safety during repairs.
• Allow the engine to cool before working on it.

2. Replace Spark Plug and Ignition Coil

• Tools Required: Spark plug socket, ratchet, torque wrench, dielectric grease.
• Remove the engine cover if applicable.
• Disconnect the ignition coil connector for cylinder 4.
• Remove the ignition coil using a socket and ratchet.
• Remove the spark plug using a spark plug socket, inspect for wear or damage.
• Install the new spark plug, torque to manufacturer specifications (typically around 15 ft-lbs).
• Apply dielectric grease to the ignition coil boot and reinstall the coil.
• Reconnect the ignition coil connector.

3. Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector puller (if needed), fuel line disconnect tool.
• Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect the fuel line from the injector.
• Remove the retaining clips and pull out the fuel injector.
• Install a new fuel injector and ensure it is properly seated.
• Reconnect the fuel line and clips.

4. Conduct Compression Test

• Tools Required: Compression tester.
• Remove spark plugs for all cylinders for accurate testing.
• Insert the compression tester into cylinder 4 and crank the engine.
• Record the compression reading and compare it to manufacturer specifications (usually around 150-200 psi).

5. Inspect and Repair Vacuum Leaks

• Tools Required: Smoke machine or propane torch (without flame).
• Inspect all vacuum lines connected to the intake manifold.
• Use a smoke machine to detect leaks or lightly apply propane near suspected areas while the engine is running to check for RPM changes.
• Replace any damaged hoses or seals.