how to fix P0302 code in BMW 3 Series G20/G21 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the engine cover if applicable.
• Locate cylinder 2 spark plug (refer to the engine layout).
• Using the spark plug socket, carefully unscrew the spark plug from cylinder 2.
• Inspect the spark plug for wear, carbon buildup, or damage.
• If damaged, replace with a new spark plug of OEM specifications (typically around 0.028 inches gap).
• Torque the new spark plug to the manufacturer's specified value (usually around 18 lb-ft).

3. Check and Replace Ignition Coil

• Tools Required: Socket set.
• Disconnect the electrical connector from the ignition coil on cylinder 2.
• Remove the retaining bolts and lift the ignition coil out of the cylinder head.
• Visually inspect the ignition coil for cracks or damage.
• If faulty, replace the ignition coil with a new OEM component.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Inspect and Clean/Replace Fuel Injector

• Tools Required: Fuel injector removal tool, cleaning solvent.
• Disconnect the fuel injector connector for cylinder 2.
• Remove the retaining clips or bolts securing the fuel rail if necessary.
• Carefully pull out the fuel injector from the rail.
• Inspect the injector for clogs or damage; clean if dirty or replace if needed.
• Reinstall the fuel injector and secure it in place.

5. Compression Testing

• Tools Required: Compression gauge.
• Remove spark plugs from all cylinders to allow for accurate testing.
• Insert the compression gauge into cylinder 2.
• Crank the engine several times to get a reading.
• Compare the reading to manufacturer specifications; if below normal, further engine diagnostics may be required.