how to fix P0301 misfire code on BMW X3 G01 (2018-2024)

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Remove Spark Plug

• Use a spark plug socket and ratchet to remove the spark plug from cylinder 1.
• Inspect the spark plug for carbon deposits, cracks, or excessive wear.
• Replace the spark plug with a new one if necessary, ensuring it is gapped correctly (typically 0.028 inches for BMW).

3. Check and Replace Ignition Coil

• Remove the ignition coil from cylinder 1 by unplugging the electrical connector and unbolting it.
• Inspect the ignition coil for signs of damage or wear.
• If faulty, replace the ignition coil with a new one and ensure it is seated properly.

4. Inspect and Test Fuel Injector

• Disconnect the fuel injector connector for cylinder 1.
• Use a multimeter to check the resistance of the fuel injector; if it is out of specification, replace the injector.
• Reconnect the fuel injector and ensure all connections are secure.

5. Perform Compression Test

• Remove the spark plug from cylinder 1 again.
• Insert a compression gauge into the spark plug hole and crank the engine.
• Note the reading; it should be within the manufacturer's specified range (typically around 120-200 psi).
• If the reading is low, further investigation into valve issues or head gasket failure is required.

6. Check for Vacuum Leaks

• Inspect hoses and gaskets around the intake manifold and throttle body for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to detect vacuum leaks while the engine is idling.
• Repair or replace any identified faulty components.