how to fix P0302 cylinder 2 misfire code in BMW 5 Series G30/G31 (2017-2024)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector cleaner
• Clear the error codes after initial diagnosis and before repairs.
• Disconnect the battery (negative terminal) to ensure safety.

2. Replace Spark Plug

• Remove the engine cover if applicable.
• Disconnect the ignition coil connector and remove the ignition coil from cylinder 2.
• Use a spark plug socket to remove the spark plug from cylinder 2.
• Inspect the spark plug for wear; if damaged or worn, replace it with a new one.
• Torque the new spark plug to the manufacturer's specification (usually around 20 Nm).
• Reinstall the ignition coil and reconnect the connector.

3. Test and Replace Ignition Coil (if necessary)

• If the misfire persists after replacing the spark plug, swap the ignition coil from cylinder 2 with another cylinder.
• Clear the codes and drive the vehicle to see if the P0302 code reappears. If it does, replace the ignition coil with a new one.

4. Clean or Replace Fuel Injector

• If the ignition coil is functioning properly, proceed to check the fuel injector.
• Remove the fuel rail, taking care to relieve fuel pressure beforehand.
• Inspect the injector for blockages; clean using fuel injector cleaner or replace if defective.
• Reinstall the fuel rail and reconnect all connections.

5. Compression Test

• If issues persist, perform a compression test on cylinder 2 to determine if there are mechanical issues.
• If compression is low, inspect for valve issues or head gasket failure, which may require more extensive repairs.