my BMW X3 G01 (2018-2024) has a check engine light with code P0300, what’s next

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, socket set, torque wrench, compression tester, fuel injector cleaner.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to ensure safety when working on electrical components.

2. Inspect and Replace Spark Plugs

• Remove the engine cover if necessary.
• Using a socket wrench, remove the spark plugs one at a time to avoid mixing them up.
• Inspect each spark plug for wear, carbon build-up, or damage; replace if they show signs of wear.
• Install new spark plugs, ensuring to torque them to the manufacturer's specifications (typically around 15-20 Nm).

3. Test and Replace Ignition Coils

• Remove the ignition coil connectors carefully.
• Using a multimeter, check the resistance of each ignition coil; compare results with manufacturer specifications.
• Replace any faulty ignition coils with new ones, ensuring they are seated properly.

4. Clean or Replace Fuel Injectors

• If injectors are suspected, use a fuel injector cleaner by disconnecting the fuel line and connecting the cleaner according to the product instructions.
• If cleaning does not resolve the issue, remove the fuel injectors using a socket set and replace them with new units.

5. Perform Compression Test

• Remove all spark plugs to allow for accurate compression measurement.
• Insert the compression tester into the spark plug hole of each cylinder, cranking the engine several times.
• Record and compare compression readings; replace any cylinder with significantly lower compression than the others.