why do I get a check engine light with code P0302 in my BMW 3 Series G20/G21 (2019-2024)

Solution

1. Preparation

• Gather tools and parts necessary for the repair.
• Disconnect the vehicle's battery to prevent any electrical shorts.

2. Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if necessary.
  2. Locate the spark plug for cylinder 2—reference the vehicle's service manual for exact location.
  3. Use a spark plug socket and ratchet to carefully remove the old spark plug.
  4. Inspect the spark plug socket for debris and clean if needed.
  5. Install the new spark plug, ensuring it is torqued to the manufacturer's specifications (usually around 20-30 Nm).

3. Replace Ignition Coil

• Sub-steps:
  1. Disconnect the electrical connector from the ignition coil on cylinder 2.
  2. Remove the retention bolt(s) securing the ignition coil.
  3. Pull the ignition coil out of the cylinder head.
  4. Install the new ignition coil and secure it with the retention bolt(s).
  5. Reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

• Sub-steps:
  1. Remove any components obstructing access to the fuel injector for cylinder 2.
  2. Disconnect the fuel injector electrical connector.
  3. Use a fuel line disconnect tool to remove the fuel line from the injector.
  4. Remove the fuel injector by unclipping or unscrewing it as per design.
  5. Clean the injector with a suitable cleaning solution or replace it if defective.
  6. Reinstall the injector and reconnect the fuel line and electrical connector.

5. Final Checks

• Sub-steps:
  1. Reconnect the battery.
  2. Start the engine and check for any abnormal noises or issues.
  3. Monitor the engine for any check engine light re-illuminating.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Fuel line disconnect tool
• Spark plug socket
• Ratchet and extensions

Parts Required:

• Spark plug for cylinder 2
• Ignition coil for cylinder 2
• Fuel injector for cylinder 2 (if necessary)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect the battery before working on electrical systems.
• Allow the engine to cool before servicing components to avoid burns.