how to fix P0302 misfire code in my BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

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

2. Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the engine cover if necessary.
• Locate and remove the spark plug wire or coil pack for cylinder 2.
• Use a spark plug socket to carefully remove the old spark plug.
• Inspect the spark plug for wear; replace if necessary with the manufacturer's recommended part.
• Torque the new spark plug to the manufacturer’s specification (typically around 18-22 lb-ft).
• Reattach the spark plug wire or coil pack.

3. Test and Replace Ignition Coil

• Tools Required: Ratchet and socket set.
• If the ignition coil is suspect, remove the coil from cylinder 2 and inspect for cracks or carbon tracking.
• Swap the ignition coil with another cylinder (e.g., cylinder 1) to see if the misfire moves.
• If the misfire follows the coil, replace it with a new ignition coil.

4. Inspect Fuel Injector

• Tools Required: Fuel injector tester or noid light.
• Disconnect the fuel injector connector on cylinder 2.
• Use a noid light to check for signal to the injector. If there’s no signal, further diagnose the wiring or ECM.
• If the injector is suspected to be faulty, remove and replace it with a new injector.

5. Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 2.
• Insert the compression tester and crank the engine for a few seconds.
• Compare the compression reading to the manufacturer’s specifications (typically 130-200 psi).
• If compression is low, further diagnose potential issues like valve problems or head gasket failure.