my BMW X5 G05 (2019-2024) has a check engine light and code P0301

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on electrical components.
• Tools Required: OBD-II scanner, spark plug socket, ratchet and extensions, torque wrench, multimeter.

2. Inspect and Replace Spark Plug

• Remove the engine cover (if applicable) to access the spark plugs.
• Use a spark plug socket to remove the spark plug from cylinder 1.
• Inspect the spark plug for wear, carbon build-up, or damage.
• If necessary, replace the spark plug with a new one, ensuring it is gapped according to the manufacturer’s specifications (typically around 0.032-0.036 inches for BMW).
• Torque the spark plug to the manufacturer's specifications (approximately 18-22 Nm).

3. Check and Replace Ignition Coil

• Disconnect the wiring harness from the ignition coil on cylinder 1.
• Remove the ignition coil using a socket and ratchet.
• Inspect for cracks or signs of failure such as burnt or corroded connectors.
• If the ignition coil is faulty, replace it with a new one and reconnect the wiring harness.
• Ensure the coil is seated properly and secured.

4. Inspect Fuel Injector

• Locate the fuel injector for cylinder 1 and disconnect the electrical connector.
• Remove the fuel injector using a socket if necessary.
• Check for any clogging or leaks in the injector.
• If it's malfunctioning, replace it with a new fuel injector and reconnect the electrical connector.

5. Compression Test (if necessary)

• If misfire persists, perform a compression test on cylinder 1.
• Remove the spark plug and connect the compression gauge.
• Crank the engine and note the compression reading.
• Compare the reading to manufacturer specifications; replace any components if compression is below spec.