how to fix P0301 misfire code in Volvo XC90 Second Generation (2015-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, noid light.
• Disconnect the negative battery terminal to ensure safety.
• Gather necessary replacement parts based on diagnostic findings.

2. Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Remove the ignition coil from cylinder 1 using a socket.
  4. Remove the old spark plug using a spark plug socket.
  5. Inspect the spark plug for signs of wear; replace if necessary with OEM-spec spark plug.
  6. Install the new spark plug to the manufacturer’s torque specifications (usually around 15-20 lb-ft).
  7. Reinstall the ignition coil and reconnect the plug.

3. Test and Replace Ignition Coil (if needed)

• Sub-steps:
  1. Use a multimeter to test the ignition coil’s primary and secondary resistance; compare to specifications.
  2. If the coil is faulty, remove it and replace it with a new OEM coil.
  3. Reconnect all connections securely.

4. Check Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Use a noid light to check for injector pulse. If no pulse, inspect wiring and connectors.
  3. If the injector is faulty, remove the fuel rail and replace the injector for cylinder 1.
  4. Reinstall the fuel rail and reconnect all connectors.

5. Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine for a few seconds and note the compression reading.
  4. If the compression is below specifications, further engine diagnostics may be required.