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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, noid light, multimeter, vacuum gauge, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface, and the engine is cool. Disconnect the negative battery terminal for safety.

2. Replace Spark Plug

1. Remove the engine cover (if applicable) by unscrewing the bolts.
2. Disconnect the ignition coil connector from cylinder 1.
3. Remove the ignition coil from cylinder 1 by unscrewing it from the cylinder head.
4. Use a spark plug socket to remove the spark plug from cylinder 1.
5. Inspect the old spark plug for wear; if it is fouled or worn, replace it with a new spark plug (refer to specifications for gap settings).
6. Install the new spark plug and tighten it to the manufacturer’s specified torque (typically around 15 lb-ft).
7. Reinstall the ignition coil and reconnect the ignition coil connector.

3. Replace Ignition Coil (if necessary)

1. If the ignition coil was found to be faulty during inspection, replace it with a new one.
2. Follow the same steps as replacing the spark plug for removing and installing the ignition coil.

4. Test Fuel Injector

1. Disconnect the fuel injector connector for cylinder 1.
2. Use a noid light or multimeter to check if the injector is receiving the proper signal from the ECU.
3. If the injector is not functioning, replace it with a new fuel injector.

5. Compression Test

1. Remove the spark plug from cylinder 1.
2. Screw in the compression tester into the spark plug hole.
3. Crank the engine to get a reading and note the compression level.
4. Compare the reading to the manufacturer’s specifications; if low, further investigation into internal engine components may be needed.