how to fix P0301 misfire code on my BMW X5 G05 (2019-2024)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, noid light.
• Ensure the vehicle is parked on a flat surface and the engine is off. Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Locate the spark plug for cylinder 1 (refer to service manual for exact location).
  3. Disconnect the ignition coil connector.
  4. Remove the ignition coil using a socket wrench.
  5. Inspect the spark plug for wear or damage; replace if necessary (use OEM or equivalent).
  6. Install the new spark plug by hand, then torque to the manufacturer's specifications (typically around 18-22 lb-ft).
  7. Reinstall the ignition coil and reconnect the connector.

3. Inspect and Test Ignition Coil

• Sub-steps:
  1. Use a multimeter to test the resistance of the ignition coil (refer to specifications).
  2. If the coil is faulty, replace it with a new one.
  3. Reconnect all components and ensure proper seating.

4. Inspect Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector.
  2. Use a noid light to test for voltage at the injector connector while cranking the engine.
  3. If no signal is detected, check wiring and connectors for damage.
  4. If the injector is faulty, remove and replace with a new one, ensuring proper installation.

5. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug for cylinder 1.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine for several seconds and record the reading.
  4. If compression is low, investigate further for potential internal engine problems (e.g., valve issues, piston rings).