how to fix P0301 misfire code on my BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

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

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, spark plug socket, anti-seize compound, thread sealant.
• Remove the engine cover if applicable.
• Disconnect the wiring harness from the ignition coil on cylinder 1.
• Remove the ignition coil using a socket set.
• Inspect the spark plug for damage or excessive wear. If necessary, remove the spark plug using a spark plug socket.
• Replace the spark plug with a new one, applying a small amount of anti-seize compound on the threads before installation. Torque to manufacturer specifications (typically around 18 ft-lbs).
• Install the new or inspected ignition coil and reconnect the wiring harness.

3. Check Fuel Injector

• Tools Required: Noid light or multimeter.
• Disconnect the fuel injector connector on cylinder 1.
• Connect a noid light to the injector harness to check for signal when the engine is cranked. If no signal, inspect wiring or ECM.
• If the injector is faulty, replace it with a new one and reconnect the harness. Use thread sealant on the injector if specified by the manufacturer.

4. Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole and crank the engine.
• Record the compression reading and compare it against manufacturer specifications (typically 140-200 psi).
• If compression is low, investigate further for possible internal engine issues.

5. Reassemble and Clear Codes

• Reinstall the engine cover if removed.
• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Use the OBD-II scanner to clear the P0301 code and any other stored codes.