how to fix a P0301 code on my BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

1. Remove the engine cover if applicable.
2. Disconnect the ignition coil connector for cylinder 1.
3. Remove the ignition coil using a socket set (typically 10mm).
4. Extract the spark plug using a spark plug socket and ratchet.
5. Inspect the spark plug for wear; replace it if it appears worn or fouled.
   • Use a spark plug gap tool to ensure proper gap (refer to specifications for the correct gap).
6. Install the new spark plug, tightening to the manufacturer's torque specification (usually around 25 Nm).
7. Reinstall the ignition coil and reconnect the connector.

3. Inspect and Replace Ignition Coil

1. If the spark plug was fine, inspect the ignition coil for cylinder 1.
2. Replace the ignition coil if it shows signs of wear or damage.
   • Ensure the new coil matches OEM specifications.
3. Reconnect the ignition coil connector and ensure it is seated properly.

4. Check Fuel Injector

1. If misfire persists, inspect the fuel injector for cylinder 1.
2. Remove the fuel injector connector and use a multimeter to check for voltage.
3. If there is no voltage, check wiring and connectors for continuity.
4. If the injector is clogged or faulty, replace it with a new one.

5. Perform Compression Test

1. If the issue remains unresolved, perform a compression test on cylinder 1.
2. If compression is low, further diagnosis is needed to check for valve issues or piston ring wear.