how to diagnose P0304 code in Volvo XC60 Second Generation (2018-2024)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Volvo XC60 (2018-2024). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect Ignition Components

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the ignition coil connector for cylinder 4.
  3. Remove the ignition coil using a socket set; inspect for cracks or carbon tracking.
  4. Remove the spark plug for cylinder 4 using a spark plug socket; inspect for wear and carbon buildup. Replace if necessary.
  5. Reinstall a new spark plug and ignition coil, ensuring proper torque (typically 12-15 ft-lbs for spark plugs).

3. Check Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 4.
  2. Remove the fuel injector using an appropriate puller if necessary.
  3. Inspect for clogs or leaks; clean or replace as needed.
  4. Reinstall the fuel injector, ensuring proper alignment and connection.

4. Conduct Compression Test

• Sub-steps:
  1. Remove all spark plugs to facilitate engine cranking.
  2. Insert a compression gauge into the spark plug hole for cylinder 4.
  3. Crank the engine for several revolutions; record the compression reading.
  4. Compare the reading to the manufacturer’s specifications (typically 120-200 psi). If low, further investigation into piston rings or valves may be necessary.

5. Test Fuel Pressure

• Sub-steps:
  1. Locate the fuel rail and connect a fuel pressure gauge.
  2. Turn the ignition to the ON position (do not start) and check the fuel pressure reading; it should meet manufacturer specifications (usually around 50-60 psi).
  3. If pressure is low, inspect the fuel pump and filter for issues.