how to diagnose a misfire in my BMW X5 G05 (2019-2024) with code P0302?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts and ensure safety.

2. Replace Spark Plug and Ignition Coil (if needed)

• Tools Required: Socket set, torque wrench, dielectric grease.
• Remove the engine cover to access the ignition components.
• Disconnect the electrical connector from the ignition coil for cylinder 2.
• Remove the ignition coil by unscrewing it from the cylinder head.
• Remove the spark plug from cylinder 2 using a spark plug socket.
• Inspect the old spark plug for wear; replace if damaged.
• Install the new spark plug, tightening to the manufacturer’s specified torque (typically around 20 Nm).
• Apply dielectric grease to the ignition coil connector and install the new ignition coil.
• Reattach the engine cover.

3. Test Fuel Injector (if needed)

• Tools Required: Noid light, fuel injector cleaner (if necessary).
• Disconnect the fuel injector connector for cylinder 2.
• Connect the noid light to the injector connector to check for pulse while cranking the engine.
• If the noid light does not flash, further investigate wiring or the engine control unit (ECU).
• If the injector is faulty, replace it following manufacturer specifications.

4. Verify Compression (if needed)

• Tools Required: Compression gauge.
• Remove the spark plug from cylinder 2 and screw in the compression gauge.
• Crank the engine for several seconds and record the compression reading.
• Compare the reading to manufacturer specifications; replace the cylinder head gasket or repair if compression is low.