how to fix P0301 code on my BMW 3 Series G20/G21 (2019-2024)

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 before proceeding.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, gap gauge.
• Remove the engine cover if necessary.
• Unscrew and remove the spark plug from cylinder 1 using a socket wrench.
• Inspect the old spark plug for damage or fouling.
• Measure and adjust the gap of the new spark plug to manufacturer's specifications.
• Install the new spark plug, torquing it to the recommended specification (usually around 18-22 Nm).
• Reattach the engine cover if removed.

3. Replace Ignition Coil

• Tools Required: Socket set.
• Disconnect the electrical connector from the ignition coil for cylinder 1.
• Remove the screws or bolts securing the ignition coil and pull it out gently.
• Install the new ignition coil, ensuring it seats properly.
• Reconnect the electrical connector.

4. Clean or Replace Fuel Injector

• Tools Required: Fuel injector removal tool (if necessary), cleaner.
• Disconnect the fuel injector connector and fuel line (use caution as fuel may spill).
• Remove the fuel injector from cylinder 1.
• Clean the injector with appropriate cleaner or replace it with a new one.
• Reinstall the injector and reconnect the fuel line and electrical connector.

5. Perform Compression Test (if necessary)

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole.
• Crank the engine and record the compression reading.
• Compare the reading to manufacturer specifications. If low, further investigation into engine internals may be required.